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d&b audiotechnik ArrayCalc vs SubAligner

By Nathan Lively

Unlike my previous post about the L-Acoustics preset guide, d&b guide’s its users to perform subwoofer alignment using their ArrayCalc simulation software. I have heard from more than one colleague that they stopped using their audio analyzer after they started using d&b ArrayCalc. With such claims of accuracy I was really looking forward to comparing the results from SubAligner.

Y7P + Y-SUB

At matched level with CUT engaged the center of the crossover region is at 138Hz.

Here’s a prediction at 125Hz.

The result from SubAligner is in good agreement. The minimum delay in ArrayCalc is 0.3ms. 1.35 + 0.3 = 1.7ms.

Here’s a link to this alignment in SubAligner.

J12 + J-SUB

With the sub level offset +6dB from the low-mids and CUT engaged, the center of the crossover region is at 139Hz.

And now the results from SubAligner.

Here’s a direct link to this alignment in SubAligner.

E8 + B6-SUB

At matched level with CUT engaged the center of the crossover region is at 144Hz.

And the SubAligner results.

Here’s a direct link to this alignment in SubAligner.

Have you done any subwoofer alignment with ArrayCalc and then verified it in the field? What were your results?

Know Your Audio Analyzer Averages

By Nathan Lively

After you take several measurements and average them together, what do you expect to see?

If these two measurements are averaged, what do you expect?

Is zero the average of -6dB and 6dB, or something else?

1 octave wide parametric filters at 1kHz

Here are four possible averages you may have guessed, depending on which audio analyzer you use.

tl;dr

  1. Know what kind of averaging your audio analyzer uses.
  2. Collecting more data is more important than the way it is averaged.

Here are demos from a selection of audio analyzers in alphabetical order.

Crosslite+ v2.0.0 8

Along with options for pre and post processing, Crosslite+ offers four different options.

“Arithmetic Average Complex” : Arithmetic mean in complex values.

“Quadratic Average Complex” : Quadratic average or RMS in complex values.

“Arithmetic Average Magnitude” : Arithmetic mean in real values in dB, with phase zeroed.

USER GUIDE CROSSOLITE REV 1.1

Does the magnitude average change with trace offset? Yes. It appears that trace offset in Crosslite is the same as a gain change.

Does the magnitude average change with phase offset? Yes, except for Arithmetic Average Magnitude.

In this test I averaged the response of two microphone cables with a second order APF inserted on one of them at 1kHz.

Se deseja saber a média de fontes separadas coerentes ou de uma curva polar, é bom utilizar a aritmética complexa.

Se é média para curvas de equalização, melhor a de magnitude em dB.

Escolhi os tipos que estão mais presentes na maioria dos softwares que possuem funções de média.

Francisco Monteiro

If you want to know the average of separate coherent sources or a polar curve, it’s a good idea to use complex arithmetic.

If it’s an average for equalization, better the magnitude in dB.

[For Crosslite] I chose to offer the types that are most present in most software that have averaging functions.

Francisco Monteiro

L-Acoustics M1

M1 offers a single kind of average, which appears to be a simple average with phase zeroed.

Does the magnitude average change with trace offset? No. There is no trace offset option.

Does the magnitudeaverage change with phase offset? No.

OpenSound Meter v1.0.5

Open Sound Meter offers vector and polar averaging.

Does the magnitude average change with trace offset? Yes, the results are the same for a measured gain change.

Does the magnitude average change with phase offset? Yes for vector. No for polar.

For in-space averaging I use polar method. For vector (complex) you need to have very close phase responses.

Pavel Smokotnin

REW v5.20

REW offers two options for averaging.

Vector average, which averages the currently selected traces taking into account both magnitude and phase. It can only be applied to measurements that have an impulse response.

RMS average, which calculates an rms average of the SPL values of those traces which are selected when the button is pressed. Phase is not taken into account, measurements are treated as incoherent. This does the same as the Average The Responses button. If the measurements were made at different positions (spatial averaging) it may be helpful to first use the Align SPL… feature to remove overall level differences due to different source distances.

REW Help

Does the magnitude average change with trace offset? Yes, but only after the data is permanently changed with the Add offset to data button.

Does the magnitude average change with phase offset? Yes for vector. No for RMS.

RiTA

RiTA offers a single options for averaging traces: Arithmetic Average Complex

Does the magnitude average change with trace offset? Yes.

Does the magnitude average change with phase offset? Yes.

The next version of RiTA will include three options for averaging.

Complex AVG: magnitude estimation is greatly affected when complex averaging is performed. It is useful when you are interested, in close measurements, in knowing the constructive and destructive interference of the sound system.

ABS AVG and dB AVG are intended for spatial averaging of several microphones. Abs AVG tends to give priority to good data and less to data affected by reflections. dB AVG gives equal weight to all data.

By default, RiTA 2.5 uses ABS AVG

Pepe Ferrer

SATlive

SATlive offers a three options for averaging: Create Sum Trace, Complex Add, and Weighted Average.

Does the magnitude average change with trace offset? No

Does the magnitude average change with phase offset? Yes for Complex Add. No for Sum Trace.

SATlive offers 3 different approaches for averaging different measurements.

1. Complex averaging: Will calculate the sum using the amplitude values of each trace and the phase relation between the traces. It is intended to average measurements taken at the same mic position, like Sub/Top time align or interference of different sources. (quick traces -> sum trace complex averaging).

2. Amplitude based averaging: Will calculate the sum by normalizing (center at 0 dB) each trace and afterwards adding the amplitude values only. This is helpful when you want to average traces taken at different mic locations (and in most cases, using the same source).  (quick traces -> sum trace Create Sum Trace).

3. Weighted averaging: This is a special version of 2. where you can assign a weighting factor to each trace (three configurable settings). This was inspired by the Primary/Secondary/Tertiary measurement approach, which I first heard about during my SIM II seminar. In fact, it does not make much sense to add tertiary traces to the result, but it would be possible. (Trace Manager)

Hint: There is a Valid only if all traces valid option for 1. and 2. where you can define wether just one valid result at a certain frequency will be sufficient for a valid result or all traces averaged must contain a valid value to create a valid result.

Which of the options do you recommend to your users for judgement of tonality and EQ operations?

Only option 2. and 3. will make sense here. I rarely work with averaged measurements during EQing. Normally I’d use the Primary Location trace as the base for EQ while the other traces help me to distinguish if the problem is global or just local.

Big differences between the different mic-locations (primary/secondary) indicate a problem that you should fix before applying the eq (redirecting the speaker, additional speaker, speaker with a different directivity pattern).

For overall tonality I’d go for 2 and for Eq-ing for 3

Thomas Neumann

Smaart v8.5.0.2

Smaart offers two options of averaging with the second including built-in proprietary pre-processing.

Decibel spatial averaging, sometimes called arithmetic averaging, is a simple average of decibel magnitudes at each frequency. Spatial power averaging is the average of squared linear magnitudes at each frequency with the result converted to decibels.

Unweighted dB averaging works exactly the same way both transfer function magnitude and spectrum averages. When you select Power averaging for transfer function measurements, however, Smaart automatically adjusts the overall level of all individual measurements going into the average according to their average decibel magnitudes in the range of 225 Hz to 8.8 kHz so that they are all approximately equal in level throughout that range.

Rational Acoustics Smaart v8 User Guide, Release 8.3

Does the magnitude average change with trace offset? No.

Does the magnitude average change with phase offset? No.

Our data is in dB, so we have to decide whether to average linearly or logarithmically, whether to normalize first, whether to weight by coherence (does it make sense that poor-quality data gets as much “say” in the final result as high-quality data?) and of course remembering that FFT math spits out complex data points, not simple integers.

So you can end up with a lot of approaches that are all valid from a mathematical standpoint, but the question becomes “which method gives us the most useful result?” (I could average together the number of socks in my drawer and the number of tires on my car, and even if my math was correct, it’s a meaningless answer for all practical purposes.) So at the end of the day, we want averaging that produces information that’s helpful to the user. If you have a bunch of traces and you average them, we have an expectation of what that final averaged response should look like. How well does it highlight the trends indicated by the individual traces? That’s what we’re looking for when we take an average, and so our averaging is designed with that in mind.

In terms of which to use, just like everywhere else in Smaart: if you’re not sure which setting you need, use the defaults. They’ve been carefully chosen over many years to give good results without the user having to tweak around. I actually reset the software to default configuration every time I use it, and I pretty rarely need to go in and change a bunch of things from that state. The primary advantage of power averaging would be if you’re averaging together a bunch of traces that have severe comb filtering (which hopefully doesn’t happen all that often). The math will give more weight to the peaks and less to the dips, so you end up with something that can be more representative of the overall response in that area and what your ear might tell you. But – in most circumstances, the differences between coherence-weighted dB average and power average end up being very small. If you create both types of average from the same dataset, and lay the two averages traces on top of each other, you’ll see they tend to agree very well. I think you’d have to come up with a pretty contrived situation or have pretty bad-quality measurement data to get a result where the power averaging and the dB averaging disagree.

Michael Lawrence

All together now

Here’s an overview of the different averages being discussed in high contrast. All of these are my own estimations since the math is not exposed and is in some cases proprietary.

Which one should I use?

Please follow the manufacturer guidelines and in most cases stick with the default settings.

The demos in this post average electrical measurements of symmetrical EQ filters in order to clearly expose the calculations being used. I want to be able to see clearly if the average of +6 and -6 is 0 or something else. Measurements of speakers in rooms will feature many wide peaks and narrow valleys instead of this symmetrical behavior.

As I worked through each demo I found myself wondering why I might use one average over another. Being visually inclined and looking at a graph, at first the simple magnitude average made the most sense.

(-6 + 6) / 2 = 0

M1 offers this as its only option and it is the default option in Smaart and SATlive.

Why do the other options exist?

If you had one subwoofer and I gave you another, how much would that be in decibels? You would add 0dB + 0dB to get 6dB.

If I gave you another half a sub you would have 8dB because 20 * log10(1 + 1 + 0.5) = 8.

Following the same process of linear to log conversion, we should calculate the decibel average of -6dB and 6dB like this:

20 * log10((0.5 + 2) / 2) = 1.9dB

Maybe it makes more sense now why some audio analyzers like REW, RiTA, and Open Sound Meter show an average of 1.9dB instead of 0dB.

Interestingly, Bob McCarthy finds even this form of average to be lacking since it does not take psychophysics into account.

Studying summation revealed that 20–40 dB dips are likely to stay down in only a small area, whereas 6 dB peaks may spread over a wide area. Studying perception revealed greater tonal sensitivity to wide peaks over narrow dips. Therefore we should be wary of accepting 0 dB as the best representative here. When samples agree, the averaging builds confidence. When samples differ, the average is suspect. There’s safety in numbers when math averaging is used: get a lot of samples.

McCarthy, Bob. Sound Systems: Design and Optimization: Modern Techniques and Tools for Sound System Design and Alignment (p. 453). Taylor and Francis. Kindle Edition.

In this case “0 dB” refers to the average of a 6dB peak and a -40dB valley.

My takeaway from all of this is that more measurements combined with optical averaging (looking at them all at once) is more important than the specific form of mathematical averaging you choose.

What do you think?

You Need A Sound System Preflight Checklist

By Nathan Lively

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In this episode of Sound Design Live my guest is by applications engineer for touring systems at L-Acoustics, Vic Wagner. We discuss sound system tuning, immersive audio, modular workflows, benchmarking performance and designing loudspeaker presets.

I ask:

  • What are some of the biggest mistakes you see people making who are new to designing, deploying, and optimizing touring systems?
  • What do I need to verify to make sure I uncover any problems that will slow me down later?
  • Kyle Marriott: Can he explain how they reach the published specs for KARA II please? What stimulus, how long for, downhill with the wind behind it, the like?
  • Lee Stevens: Especially as they use the same components at KARA, how have they achieved the extra SPL?
  • Dave Gammon: Immersive sound is a huge new area of development. Do they see all large format production moving to L-ISA Format?
    • Explain the reasons why they don’t use SMAART as a defacto tool for system calibrations.
    • Why do you use sine sweeps for your measurement stimulus instead of a broadband signal like pink noise?
  • Tom McKeand: CA-COM… why?
  • Chris Prendergast: Detail how ‘their’ wave sculpture technology has developed over the decades
  • Ben Heavenrich: In his opinion, what separates L’Acoustics from the rest of the pack?
  • Stage Craft: How they design their presets?
  • b.meiners: How to achieve tonal balance with smaller line arrays?
  • Christian Friedrich: If smaller boxes are used for downfill at the bottom of the array, won’t that produce the same problem as gain shading?
  • Christopher Pou: Vic’s had quite the career, being an SE for such notable mixers as Scovill and Pooch. If it’s within reason to venture outside of the brown box realm, I’d be curious to hear his opinions on some other rigs he’s deployed; I’d say most curiously ANYA, as it stands out above others considering the flexibility it offers in terms of DSP-based steering and control.
  • Yves Smit: Can I combine kara and Kara-2 in an array?
  • Dan Barrett: How many toddlers does he think he could take in a fight?
  • Nico Díaz: Stereo vs Mono: If the stereo image is mainly enjoyed by few out of many, in a live event, could a single wide dispersion line array provide a more uniform coverage?

It comes down to identifying a workflow and a checklist specific to verification and calibration.

Vic Wagner

Notes

  1. All music in this episode by Mello C.
  2. Preflight checklist: In aviation, a preflight checklist is a list of tasks that should be performed by pilots and aircrew prior to takeoff. Its purpose is to improve flight safety by ensuring that no important tasks are forgotten. Failure to correctly conduct a preflight check using a checklist is a major contributing factor to aircraft accidents. –Wikipedia
  3. Touring Systems Optimization: Modular Workflow for Efficient Calibration
  4. workbag: TruPulse Rangefinder, P1, iSEMcon EMX7150
  5. Books: The Complete Guide to Highend Audio, Idea Factory, Failure Is Not an Option,
  6. Podcasts: Switched On Pop
  7. Quotes
    1. It comes down to identifying a workflow and a checklist specific to verification and calibration.
    2. We want to think about obstacles that can disrupt our workflow.
    3. Reach out to the manufacturer and immerse yourself in their recommended guidelines.

Transcript

This transcript was automatically generated. Please let me know if you discover any errors.

I’m Nathan Lively, and today I’m joined by applications engineer for Touring Systems at L-Acoustics, Vic Wagner. Vic, welcome to Sound Design Live.

Glad to be here.

So I definitely want to talk to you about sound system tuning, immersive audio and designing presets. But before I do that, after you get a sound system set up, what is one of your maybe favorite pieces of music to play to just get familiar with it?

I don’t think you’re going to like my answer here.

I’m not going to like it.

I’m a big fan these days of virtual playback. I’m a big fan of once you get the system calibrated to, you know, get some playback from a show previous or some kind of tracks and try to optimize or maximize the signal flow of your drive systems of console to any outboard gear and then kind of use that as the most accurate stimulus for for kind of verifying the system or do any kind of critical listening.

No, that’s perfect. That’s the thing that’s like freshest in your mind and you’re most familiar with because you have been working with it for the last who knows how many days. So as soon as it comes on, you’re going to immediately get a bunch of information.

Yeah. Now, my thing is, is that I think it’s good to do some ear training. It’s definitely good to dig into some hi fi stuff, dig into some kind of reference tracks and things like that, and think about scale. Think about listening to those those tracks on different sized systems. But that’s really just to kind of get an idea for frequency response and kind of how systems respond at different levels. But I think these days I just especially in the touring domain, is to really think about using content that’s relevant to the to the production.

And I think it’s pretty easy to do with modern mixing consoles. I mean, you can do it with a variety of different doors. And every every professional console allows you to play that back through the system. And I think that’s just a good kind of step towards verification to make sure all your outpoured gear and everything in the signal flow is working properly and acting responsibly as you like. So.

So how did you get your first paying gig in audio?

You know, this is kind of goes back to see maybe grade school days kind of volunteering at the community theater, honestly, just kind of working for some variety shows and mixing my buddy’s bands and and kind of doing some some high school musical stuff, drama club, those kind of things. But I think we’re really kind of took form, so to speak, being like, hey, well, this is something that I that I could do professionally is working with some some regional providers and kind of seeing some guys that build their own speakers kind of in the garage.

And that’s where I really understood this is a career path that, you know, is very scientific and exacting, but also musical and offers a fair amount of, I guess, esthetic leeway, so to speak.

And did you start working with those guys?

Yeah, I mean, it was it was doing shows in parks and kind of festivals and things like that and kind of kind of seeing, you know, we had to better get bigger systems and mixing with them and things like that.

How did you meet these guys who are doing who were building speakers in the garage? I’m just wondering, like, if I wanted to kind of recreate your path a little bit, like what are some things I should do to meet people who are doing shows and building speakers?

Well, it’s a little I think it’s a little more professional these days in in regards there’s a, you know, brands that focus on these kind of things. But this was, you know, me volunteering. And as the shows got more complex and, you know, touring, artists came in and expect larger systems or more complex systems. You know, we needed larger wedges. And this is obviously the day of days of wedges where I feel like a lot of the stuff is kind of in the erm domain these days.

But, you know, more complex kind of systems kind of comes up and in there. I think that that’s, that’s where we just kind of expanded and we had, we had to provide larger systems and those companies came in and I was, you know, volunteering or working kind of hourly wage at these places for for larger productions. And then and I guess I mean, you’re in Minneapolis, growing up in the Midwest, a lot of kind of summertime festivals going on.

So I was involved in that kind of circuit early on and able to kind of see what other people are doing and what touring people are doing.

Sure, I actually grew up in Texas, but the way my experience, the way I see my experience related to yours is that it was really helpful to work in a place where a lot of different artists were coming through. And I met a lot of people that way, which kind of helped me just see how work was done and also just start building relationships that later on could help me find work and do different projects.

Yeah, exactly. Now, speaking to that, I was just I was on a panel a couple of years back talking about kind of getting started and, you know, kind of these questions about how you can get an introduction to this industry. And I remember fondly reading kind of magazines, it was a bunch of trade magazines and stuff and all these kind of journals and. Realizing that at a pretty young age, that there’s a there’s a world out there like really professional potential, you know, there’s people that are doing this professional, there’s better products, there’s better you know, I always kind of think jokingly back to like, you know, these furry box wedges that are kind of the size of a small couch, know, and that’s very homemade.

But there’s better ways of doing things. And there’s a there’s a whole world of science and industry standardization that appealed to me. And I was kind of something that I want to become more a part of. But I think I wouldn’t have been aware of that potential without a lot of these kind of resources not getting these days. A lot of that stuff online and, you know, podcasts like this and that good in a way we all had and have gear envy you.

We want to get your hands on that stuff. And you kind of read these magazines and you can kind of feel bad like, oh, I’m not good enough because I don’t work on that stuff yet. But in your case, it also sounds like it was motivational and you’re like, oh, there’s this whole other world out there. And that’s kind of what you had your sights set on.

Yeah, totally. And that’s it was hugely. And I think that’s we need to make sure that those industries are thriving. And, you know, people students have access to those kind of things and those kinds of resources.

So, Vic, looking back in your career so far, can you take us to a place where things changed for you? Was there a moment when you decided, OK, I’m going to stop doing this thing and start doing this other thing? Can you tell us about maybe an important decision you made to get more of the work that you really love?

Yeah, you know, I kind of thought about this a lot of different angles. And, you know, I could talk about different gigs or different tours I jumped on and things like that. But I think we’re what really kind of ticked in the last decade or so of my career is that I found this kind of reward to really take the time to share my knowledge and experience with others and kind of teach some of these higher level skills and workflows and ultimately just inspire people.

And I kind of I think that was a really pivotal kind of decision. And I was thinking about it yesterday as I was looking through these questions. And I think that I could identify one place we were on tour, the big pop tour, and we had kind of a friend of a friend of a friend of the production had asked if we could have a some kind of production students and from the local college kind of come by and, you know, take a tour.

And it worked out really well where we were doing kind of we were kind of doing two ANORO shows. So we load in. And then we had that morning to kind of tech stuff and, you know, maybe have some time off and things like that and maybe get some rest because it’s kind of a strenuous schedule. But I took the time to get up early and kind of take these kids. Well, I guess a college kids, you know, young adults here through our I mean, everybody was kind of the lighting guys offered their their detail and their system.

And then I got to talk about front a house and kind of design and configuration and things like that and our our different system networks and things like that. And I just all all these guys are just really, really inspired by that. And we kept in touch over email and text and stuff over the next couple of years. And I think that that was a moment where, you know, I just took a couple hours out of my morning to talk about what I was, what I do and what our workflow is.

And, you know, these guys were just blown away by that. And I thought that’s a really rewarding feeling. And, you know, if that means that these guys are going to go and get a better result out of there, out of there, their productions or their deployments, I think that’s that can go a lot further than than anything else that I can do personally.

So so Vic, at this year’s LESSONED Summit, your presentation was called Touring Systems Optimization Modular Workflows for Efficient Calibration. And that, I think, is kind of a long title for basically saying being ready. And I’m so happy that you talked about this, at least on some. And if people want to watch your video, they can do that. A live Sound Design Live 20 20 does Sound Design Live dotcom. But the reason I was so looking forward to it is because you and I had a conversation earlier this year, in January, February, I think, where I asked you, like, what is the biggest challenge you see other people having out in the field?

And you said something to the effect of people are kind of not ready. They need to be prepared for any eventuality. They don’t have enough information. They’re not flexible enough. So things change, things go wrong, and they just like not ready, not handling as well as they could. So is that how you see it? And if so, how can I kind of think through some of these things and be prepared without just learning them all the hard way and going through all the thousands of mistakes that you and everyone else has already gone through.

So I think what this kind of comes down to is identifying a workflow, identifying checklist. And from the start, when we see that we kind of talked about in the system optimization presentation is looking at collecting information, talking about specifics, the calibration target verification and then calibration, but having kind of a. Checklist, a mentality of a checklist and a plan, and I say the plan of, you know, acquiring information and making sure certain parts of the system are determined and scaled adequately.

So there’s not any issues as we go through the verification process. And I think, you know, it acoustics. We spend a lot of time kind of thinking about this stuff internally and definitely teaching that in our in our trainings and then obviously kind of providing vertical solutions so people can can use this within our ecosystem. So I think, you know, it’s pretty easy for small deployments, but it becomes critical to stay sane and kind of keep on task and, you know, have a comfortable workday when you’re on tour.

So it’s even more important in those high pressure environments. And, you know, that was kind of one of the things I wanted to really bring to the to the live sound summit and really kind of exposed to the masses and kind of start a further conversation about this.

And, yeah, so that that makes a lot of sense to me. Work from a checklist, don’t make assumptions, have a plan. So the first thing that I wonder is can I just use your checklist? Like if I just had a copy of your checklist, would that work or would that not mean anything to me because yours is so personal? Or I guess I’m also realizing that a big part of your job is probably helping people build their own checklist before they go out on tour so that they have a plan.

Yeah, you said it. That’s that’s definitely, you know, helping people build their checklist and kind of work through those things. So I think a lot of that kind of comes down to preproduction planning that we talked about, this idea of kind of benchmarking system performance. So like thinking about what’s the audience coverage requirements, what’s the SPL distribution over the audience, what’s the target frequency response and how does that fit within different PHIL systems or coupled systems like flown sub, overground, sub, those kind of things, front fill out, fill delay speakers identifying those things across the board and then looking at where the the mics reference position is and then kind of consider source type and like what are the maximum SPL requirements?

Where do we need to stop coverage, start coverage? Is there any kind of mitigation if it’s an outdoor venue? So I think those are all really, really important things. And then yeah, then I think that that’s you want to determine the quality or the type of output bustline. Like I said, it was a very, very stereo mix as a dual mono. It’s an immersive mix. Is it left center, right kind of arrangement, things like that.

And you want to identify those things and ask a lot of tough questions and, you know, go through the process of designing different renditions or kind of being able to scale different parts of the of the system to adapt to those kind of things, to put the best solution forward for the bid or for the the writer. I kind of think about those things as far as and I think that’s one thing when you asked helping people is kind of thinking about how to scale through our product range.

So one of the things I kind of I just put a little quote on here is like when the only tool you have is a hammer, every problem is nail. And I’m sure you’ve heard that before. But, you know, not every show needs to be deployed with a bunch of K one and cast twenty eight things like that. You know, we want to think about what are these frequency response requirements, what are the Aspell requirements, what are the coverage requirements.

And maybe we can do something that’s a little less invasive and provides a higher quality experience for the audience and the obviously client.

See so when you say modular workflows, then there’s parts of it that are going to change depending on certain variables. So can you kind of give me an example of that? Is that related to benchmarking or I guess you just gave us an example, which is you might not need all of the front fills that you had in the last location.

Yeah, exactly. So, yeah. So examples of the kind of modular stuff then. I think what we want to do is kind of build into the system some flexibility. And I think that’s one of the things is kind of have some quick ways to pivot. If something changes, if there’s a different audience configuration or different seating configuration or maybe like a VIP area that you didn’t anticipate or something like that, you know, have those kind of things.

But as far as verification before the calibration process, I definitely think we want to think about obstacles that can disrupt our workflow. So power everything up, make sure everything has adequate power, make sure network is connected, make sure you know your file is correct. The network manager file, for example, before you send that stuff, make sure you’re the left is going to the left amplifiers. The right is going to the right for those kind of systems.

Everything is bust and summed properly if you’re doing any of that kind of stuff out of the console. So I like to say kind of a go no go checklist policy of, you know, is the are these items on the network if they’re not on the network, like figure out why, you know, is there under voltage over voltage issue, check those kind of things. And I just being kind of a space nerd, I think, like we want to think about aerospace safety checklist, culture of checklists, you know, a preflight.

Analyst and think about, OK, if this isn’t working, we need to identify that problem before we get further in our day and it becomes more of a looming concern that’s going to slow down your your workflow.

I see. So in part two of your process here, modular verifications and calibration that it gets as detailed as here are all the things I’m expecting to see on the network. And so potentially, if this amp doesn’t show up and it’s throwing some kind of error, now’s a good time to solve that instead of moving forward and just hoping that it’ll get solved and then it becomes a bigger problem later on.

Yeah, I like to think too is like, OK, well, maybe there’s a problem with one of the amplifiers on House Left, you know, maybe you or someone part of your touring crew or whatever can look into that problem while you move on to a different task and then say, OK, let’s get that sorted out. Maybe I’m going to calibrate using the right side of the system, or I can move into another kind of part of the checklist, kind of chapter of the checklist, maybe verifying all the front of house outboard gear is working properly and set to the correct positions after being bounced for a thousand miles down the road.

Well, the problems being sorted out on on house after house. Right. But I guess I’d hate to see a situation where you start the calibration process and realize that a portion of the system’s not working properly or not working at all. Let’s just say, for example, like one circuit isn’t passing audio out of the system, and now you’re in a situation where the wavefront integrity of the system isn’t actually how it was predicted when you did the design in the morning.

So I think that’s something, you know, that we want to kind of avoid. So we’re not chasing our tails or making decisions out of out of incorrect data.

Sure. So. So these checklists are designed to help us remove as much human error and mistakes as we can. And so that’s what I want to talk about now. Like, I’m guessing that you have seen a lot of things go wrong and you’ve made mistakes, and that’s how you’ve really developed this complete process of how you should do preproduction and be prepared for anything. So I was wondering if you could share with us maybe one time that something has gone really wrong for you.

Yeah, I mean, there’s a lot of a lot of good examples here. I mean, I think that some of this stuff is, you know, you like I think that one of the best things about touring is, you know, you kind of try some stuff and you say, well, that didn’t really work that well on this today. So we’re going to try to rethink that that strategy for tomorrow. And we’re going to do a better job of executing that plan in the future so you can take the whole rig down and reconfigure the system and kind of come back the next day and and fix any of the mistakes or any of the disadvantages of the system going forward.

But one of one of the actually pretty funny, I was on a tour and the pop star had an iPod, iPod mini for music, and this thing was probably five, six years old, out of date. And I yeah, I guess we have a lot at front of house. You have a lot of computers and there’s a lot of like record computers and playback computers and different computers running different levels of professional gear and prosumer gear and very consumer gear.

And so I get my eighth inch to excel or whatever doohickey we need to have to get this to plug into the console. And I hit play and I had some guests at the show that day. So this is kind of before doors and we’re chatting and back to catering and get get some lunch and and I get a call on the radio. So there’s a problem with the walking music, what’s what’s going on? And I go, OK, well, I’ll walk out there and and see what’s going on.

And it turns out that what I had done is hit repeat on that song instead of the entire playlist. So this Adele song played for like an hour and a half. And meanwhile, pop stars pop star’s Twitter feed is just blowing up with, like, what’s up with Adele Halcomb? Like, the song is on and it’s at a at the Hollywood Bowl. So it’s a pretty high profile show, so to speak. And and I you know, my clunky fingers had just clicked the wrong button and, you know, kind of entertaining guests and stuff.

And I had managed to put this song on repeat, put the song on repeat and and walked away to catering for a duration of time. And and now everybody in management, Don, was furious at me.

And it’s amazing. So long for someone to notice.

I mean, people noticed all over Twitter. It was a whole it was the whole thing. Twitter itself, you know, no one working there did.

Yeah, exactly. Eventually the management took me in the office and dressed me down pretty good about how stupid I could be. And so you get the you know, I think. Well, yeah. And I think that was kind of one of the gets more of a psychological or sociological kind of lessons for me was was you know, they came in and these obviously these managers are under a lot of pressure because it’s a pretty high profile show. And, you know, let me have it yelled at me for 20 minutes and, you know, told me how bad of a system engineer I was and sound guy and everything else.

And I and I just kind of I try to stay calm and I apologize. I’m sorry. It’s my fault it won’t happen again. And I just told them that I think the best thing was just to not to pass the blame, not to blame any of this equipment that we we were using. And it was entirely my fault for not maybe reading the instruction manual on the iPad mini from 2001. And, you know, one of those things where I just kind of brush it off and continue with my day and make sure that mistake doesn’t happen again.

You know, I thought that was a pretty good, kind of laughable, pretty low key kind of thing. But at the time it seemed like the end of the world.

Oh, my God. Yeah. I mean, I was I was laughing with you about it, repeating over and over again until you started talking about the meeting where people are yelling at you, because then I’m thinking about the meetings I’ve had where people have yelled at me and I’m like, oh, God, I feel terrible now. Oh, but yeah, you said and that’s it’s so true. It’s so hard to not just try to make the guilt go away by directing it somewhere else, like, well, that person shouldn’t have given me an iPod.

That’s ridiculous.

Exactly. Yeah. And I think that’s one thing is OK, well, maybe we should kind of rethink how we’re doing this, rethink how we’re playing house music and, you know, use something is a little more professional and less prone to fat finger syndrome. Sure.

So that went on your checklist. If an artist ever hands me an iPod, figure out how to not use the iPhone.

Correct. And, you know, not to mention the thing, the twenty year old battery or whatever, you know, goes dads, you have to have some kind of adapter. And, of course, you know, Apple changes the the type of power connector every couple of years. So you have to, you know, dig around to find the correct adapter. It’s one of those things where a lot of professional gear, but a lot of times it’s a lot of consumer level gear that you’re using on these on these tours.

So so, vich, I’ve been trying to kind of keep my mouth shut and also maybe talk faster than normal because I usually try to get people to send me questions ahead of time. So I’ll post on, you know, LinkedIn and Facebook and say, hey, what questions you want me to ask Rick Wagoner? So many questions came in for you, like way more than I’ve ever had for any other guest. So either, you know, the acoustics product is either like, you know, very exciting or controversial or both.

But but people had a lot of things to ask you. So I want to get into those because I thought, you know, they’re good questions and also just, you know, want to want to satisfy people’s curiosity. So thank you for agreeing to talk about some of these, you know, some of them are kind of maybe too general. And so we’ll see just like what what how can we speak to them? But you’re used to this, so.

Yeah, absolutely. All right. Let’s dove into it. So, Kyle Mariotte, can he explain how they reached the public specs for Carra to please what stimulus for how long downhill with the wind, et cetera? And I put under here another question. OK, I’ll get to that in a second. So, yeah, he wants to know, like, the, I guess, measurement process for getting the things that then get published on the MAPP XT.

But there’s a lot of things on the spec sheet. So I guess I should’ve asked him what he wanted you to focus on. But so I guess you can pick like what do you want to talk about in terms of what goes on the spec sheet and how those numbers are arrived at?

Yeah, you know, there’s a I think one of the kind of things that we pride ourselves on our acoustics is doing a lot of critical listening. So I’ll I’ll kind of I’ll talk about some of the some of the kind of product goals I think about, you know, where do we where do we want a new loudspeaker or product that we’re developing to kind of fit in the in the marketplace or in our ecosystem or our kind of our lineup of of products, whether that be a series like one Kata Carta or the coaxial, things like that.

So I kind of think about what the what the form factor is going to be, what the restrictions are going to be, and then kind of start the design process. And then you want to specify drivers, elements and kind of loudspeaker enclosure sizes and things that are going to work out well for touring. And if that’s if that’s the market you’re going to going for and then. And then and then start development. I mean, again, we’re looking at some anechoic information, some interpretation between the different drivers and poller response and stuff that kind of happens at the R&D level.

But ultimately, I think what we what we like to do as a team is develop a system and kind of have a preliminary product and then, you know, have some listening and really kind of think, does this sound good at different levels? How does it sound coupled with different or proposed kind of a subwoofer system, things like that. So it’s a very, I would say, musical and kind of organic process and, you know, take some notes and think about different kind of features we might want to have, whether that be acoustic or kind of rigging bits or rigging features.

So that’s that’s one of the things. Now, again, Kartu is a little more complex as far as public polished specifications. Again, all these lines, source systems are elements that are coupled sorry. There are elements that are coupled within a larger a larger line source. So they don’t normally do themselves and that they do. We’ve got a couple feet fill presets, underscore F.I. would be in the in the preset library that are optimized to operate independently or by a single enclosure’s.

So when we’re thinking about this published specification, we really need to look in prediction to see how they operate cumulatively with other sources in Aline’s or other elements within a line source. So and then with carto there’s a D pad flex fense that allow you to adjust the horizontal activity. So I just pulled up the the specification sheet. I’ve got it here and I see that the maximum spell is listed at one forty two and it’s noted that this is defined with the car to 70 preset.

So what’s going on is those pen flex fins are in mechanically increasing sensitivity on the in the high frequency domain. So again, that’s, that’s how you get that higher SPL. But there’s going to be a different sensitivity if you go to a wider. So there’s just literally less surface area on the waveguide. If you go to in the case of two, you could go asymmetric 90 or 110 coverage. So I think you have to kind of think about what your design objectives are, think about how these elements are functioning within a line source, and that’s probably the best approach.

Okay, cool. I hope I hope that kind of helps answer the question.

Yeah. I mean, that wasn’t where I thought you were going to go with it, but that’s cool. It’s kind of like you, you almost have the specs ahead of time and you say, OK, what do we need to do mechanically, electronically to make this work out? Now, Kyle did specify he’s curious, like what stimulus was used and how long do you know what he’s asking for there?

I guess some R&D stuff would be, you know, looking at pink noise or looking at some sign sweep’s prescribing, I guess, kind of some fluid dynamics for Sabal for systems are looking at some more complex kind of airflow things in the porting. So, you know, I, I think without getting too kind of in the weeds as far as the R&D side of things, you know, there’s a variety of different different things that go into into place.

And a lot of it’s these days is done in production, you know, using kind of computer models and like I said, kind of fluid, fluid dynamics models to look at how things, especially for low frequencies, are longer wavelengths. React with importing and heat dissipation and thinking about Kresse factor, so to speak. So, you know, again, I think that’s one thing if if, you know, we wanted to get more into it, I could I could discuss that exclusively.

But I think there’s other people in the R&D team that could speak to this much more in depth, so to speak. Right. Well, I’ll just ask a follow up question from Lee Stevens then, who says, especially as they use the same components, Kyra, how have they achieved the extra? SBL So he’s saying that car and to have the same components and yet car has a different spell on the spec sheet. Is that what he’s asking?

Yeah, exactly. So what he’s asking about is this difference from output spel because of the different waveguide use or the flexible waveguide, the pan flex waveguide used in car two. So I think the important kind of term here is mechanical sensitivity. So we’re just increasing the surface area, increasing the radiating surface here and we’re talking about line source systems. And obviously that’s going to affect the horizontal so that the kind of the polar response, the horizontal coverage, like we talk about 70, 90, 110, but also but also allow you to kind of use this system to accomplish a different speed distribution goals, to maintain consistent speed distribution for most designs.

So that’s kind of how the components are the same. And I think one thing that’s kind of commonly known is this upgrade kit allowing you to put take your existing car and upgrade them to car two. OK, so we just changed that waveguide and then we use the same transducers or motor components to get the same results. Just the different waveguide allows us to get a little a little more extra spel if desired. Now, remember that this is in the high frequency domain.

So below 1000 hertz, the eight inch drivers in the car, everything is going to perform the same as far as output SPL. So we’re only mechanically increasing high frequency output as well because it has to do with the waveguide especially.

And since you mentioned waveguide, should we jump down to this kind of difficult question from EHV simit? Let’s see if you have anything to say about this. He says, I’ve asked this before during the release them of the car two and none of the staff on the convention or demo could give me a definitive answer. Can I combine Carra and Karuta in an array using the new presets or a combination of old and new presets? I’d love to use the upper boxes with the narrow dispersion in the lower with the car one which many companies are you have in stock because the boxes are the same except for the upgradable waveguide.

The No, you can’t do it, but I can’t explain to you why answer sounded me like he was just trying to sell the waveguide so would love to hear the technical details. Not everyone has the money to upgrade all their cars, stock and this way maybe with some price delay. So if I’m understanding this correctly, I think he’s kind of asking, can I do this without the upgradable waveguide if there’s some other preset as some other way to accomplish, is that how you’re understanding the question?

Yeah, yeah. Obviously it’s difficult because I love to tell customers and tell people that these, you know, engineers kind of. Yeah, anything’s possible and we’ll customize this and customize that. But remember that if you model an array and sound vision, so if we model legacy car with car two within the same wine source, there’s going to be different coupling and kind of final parameters. That sound vision is taken into account. And the software doesn’t allow you to combine those because there’s honestly different acoustic properties, different presets that are derived that have been updated between Kata and original Carra.

So the results would be difficult to predict in in sound vision. And I think that that’s that’s one of the things where there’s only so many kind of choose your own adventure logic flows that we need to we want to prescribe in sound vision because essentially the within the same line source, these these sources are going to act a little bit differently because of that different waveguide.

All right, I don’t know.

Yeah, but now I think what’s important to realize is that if you’ve got these Carra, let’s say as an outfit and then you’ve got another maybe like a 270 field and you’ve got another, like rehang fill in one’s cartoon ones, Kyra, we’re going to be able to predict those two systems and they’re going to have the same kind of sonic fingerprint that’s the same between the two sources. And that’s an important goal that to us to make sure that legacy car is going to sound similar or there’s going to be they’re going to be kind of backwards compatible when they’re used in independent source, independent sources.

OK, so I think that’s something where if he if he’s in a pinch and there’s a situation exactly like that, I could he could reach out to us and we could probably offer some recommendations. But again, it’s difficult because we don’t have the ability to. You can’t that’s not a logic path. And some and so it’s hard to we’re making a lot of assumptions about interferences in the near field without that information and sound vision. So.

Dave Gamon has a few questions for you, immersive sound is a huge new area of development. Do they see all large format production moving to the Lisa format?

Yeah, I like that question. And I like yeah, I agree. It’s it’s a huge it’s a huge new development. But the short answer is no. I think it depends on the priorities of the production, the artist, the mixer and even the vendor. So that’s kind of the short answer. So again, and I think one thing that’s just kind of go break down all of those again, the production, you know, may not be interested and their priorities may be and other things like video or automation, things like that.

So, you know, maybe that extra complexities or the, you know, changing from the status quo, I mean, a lot of that, that’s kind of a lot of the thing, kind of a lot of it kind of comes down to is just a diversion to change. This is the way we’ve always done it. We’ve made lots of money in the past. We’re not going to change anything in the audio department. And I think everyone in our industry has kind of heard that in various forms over the over their career.

So that’s one of those things. Again, the artist may not see this as something advantageous. So I think that’s one of the things and a lot of these decisions kind of do come down from production of the artist. Now, again, Mixu, I think this is a little more kind of in my lane as far as things I deal with a lot. So I think what’s important here is that many front house mics are developed kind of a resume and on their artistic abilities to manage comparative levels of inputs and then also work with kind of dynamic range and compression frequency response limitations that are suited to dual model mixes or stereo mixes.

So, again, if that’s kind of your niche on your resume, then the ease of use or the the high definition kind of deployment where it’s we’re dealing with more of an immersive mix or a spatial mix where that’s some of these things with carving a hole and the frequency response of different inputs and dealing with managing the dynamics, the limited dynamics of a dual mono system, especially when you’ve got a lot of inputs that arrive at the same band pass and same kind of loudness, you know, and you know, again, those are all kind of carryovers from the studio environment where we’ve got a stereo system.

The status quo is stereo, and we’re going to do different tricks to those mixing busses to get different things to stand out because our limitation is stereo or dual mono. So I, I think that’s that’s one of those things. And then obviously a vendor, that’s one of those things too. You know, again, the knowledge base of the vendor, that’s something that they might not be interested in pursuing. So, again, to assume that everyone’s going to adopt this technology right away, I don’t think that’s that’s a really personal I don’t think that’s an assessment that’s that can be made.

So he also wants to know why Elka’s decided to develop its own measurement platform. So you guys have the P1 meone now. And I guess he’s wondering why you did that instead of just adopting, I guess, any other audio analyzer out there, your smarts that live fire capture ET.

Yeah. So let’s see here. What do I start in the touring domain? I think that one of the things is basically blasting pig noise through for hours is pretty lame. It’s definitely disrespectful to other departments. So that being said is what can we do and what’s known about the system already? And, you know, there’s a lot of vertical integration with the acoustics ecosystem as far as the drive system to, say, P1 going to amplify controllers and then a preset that’s designed specifically for that speaker, the performance of the system, the total balance of the system is already known and prediction.

So there’s a lot of unknowns about the systems system already and a good amount of information kind of known about the atmospheric environment that the systems operate in it. So I think what can be said from there is that we we have so much information available that we just need to kind of build an environment or decision was made to build a piece of software to kind of automate that data collection, look at user evaluation and then kind of match that with the control capabilities already existent in our control into our network manager and network manager.

So that’s kind of where someone is born, is there’s all this data kind of already available and that improves the coherence or the quality of the transfer function. And I mean, again, other FFE analyzers, they’re good and they have a lot of functionality and they’re great. But they are assuming that there’s there’s so many unknowns about how that how the measurement compares to the actual performance of the loudspeaker that’s being tested. That looks interesting. Yeah, it does, because I’m understanding that it was actually the next logical step.

If the system already knows so much about itself and really the only the next missing piece is knowing what the responses of the system at this point where this microphone is and where that microphone is. But otherwise, it already had a lot of that information. So it wasn’t like you were building something from the ground up. You were really just adding. Another piece of the puzzle.

Mm hmm. Yeah, and I think I mean, there’s a couple other things where you can collect data and save magnitude data with minimal noise and more accurate acoustic stimulus. So you basically you’re going to run a bunch of sine sweeps, collect this data from a bunch of different measurement locations, and then you can use post-processing to really predict look at coupling, to look at equalization results with better statistical averages averaging because you can collect a bunch of information about the system at different places and see how the system is going to perform in the front of the room versus the back of the room.

And then, yeah, and then calibrate that system either connected to the amplifiers or do it offline. I know, like for a lot of installations and stuff, come in, collect acoustic data and then go back to the office and actually calibrate the system or do this online as well. You to the amplifiers and you’re pushing the system in real time, pushing settings to the system in real time, and then allowing the user to say, well, let’s see how you say I fired my virtual my virtual playback and I start listening to the system.

Lets see how these different options react in different parts of the coverage area. So I think that’s a good take away figure to optimize using these using them one for sure.

And just to wrap up, we are already getting into it. But Dave asks, why do you sign sweep’s for your measurement stimulus instead of broadband signal like pink noise? But you’ve already mentioned that it’s faster, so it doesn’t bother people as much and it’s a very robust stimulus. Is there anything else you wanted to add to that?

Yes. So this concept of kind of making sure the system, the transfer function is linear, you know, we obviously are going to put this stimulus into the system. It has a discrete asynchronous start time and it excites each frequency along the way. The transfer function in the phase domain and time domain can track that and compare that input to output, just like transfer function, transfer functions do or foot transfer functions. And so this results in a better signal to noise or a more linear response.

So obviously it’s up to the user. And part of that whole, like, validation process I was talking about is making sure that input stimulus isn’t clipping the inputs to the amplifiers or outputs to the amplifiers or you’re measuring microphones and things like that. So those are all important things to check before you begin. So I think that’s a better signal to noise. ISO is kind of the one of the bigger selling points and obviously results in better data collected.

OK, Tom McKean says COCOM why so COCOM is a proprietary cable connection multi pin system. Right. So I guess you want to know why you guys decided to to make your own so partially historical. Also kind of a reliability thing dating back to the Vidocq days, the COCOM. Com Connector was picked over, other ones, other types of connectors. So again, this is the for the era of in late Connector’s, I think back then it would have been up for pretty common or EP eight.

So if you guys have ever had the exciting job to climb some speakers or land and kind of correct any of these dodgy connectors, it’s can be quite frustrating. So I think that’s one of the things is we found that can actually be quite reliable and, you know, somewhat watertight, durable over the years of touring abuse and things like that. And I think anybody who’s especially in the touring world, you kind of get in the habit within Elate Connector’s or email for is putting this back twist on the cable so it doesn’t unplug itself when it goes up in the air.

So because maybe that little pin is a little locking, pin is missing or about to fall off.

Oh, yeah. And parts of the elastic, right.

Oh yeah. Yep, yep. And so if you’re doing a, you know, Canadian run and in January and, you know, negative 20 degrees and all that plastic is, Brid, a lot of loadout that you run the risk of breaking all these connectors. So try to get a solution to our customers. That’s not that’s less fragile in those kind of things.

Chris Prendergast wants to know how the waves culture technology has developed over the decades, specifically for acoustics.

Yeah, so I think there’s a couple things here. This is actually a lot to unpack because this concept’s been the same again, thinking back to some early 90s white papers where, you know, using this stuff, the physics hasn’t changed at all. But our ability to kind of look at more computer modeling, improve the industrialization process and scale that waveguide the technology, we’ve sculpted technology into larger products, into smaller products, evaluate things like harmonic distortion or things like that.

So obviously we’re able to look at that on the vertical domain, provide for the line source systems, kind of enthrallment angles that optimize on the vertical domain, and then also do better to control what’s going on in the in the horizontal domain. So like we talked about with Kartu earlier, is looking at introducing inflects, for example, where you can control not only output sensitivity of these line segments, but also also the activity in the horizontal domain and then obviously making sure that maintains consistent and predictable poller response that’s predictable and sound vision.

And then the sound vision results are translating accurately to that physical deployment. So I think a lot of it comes down to better information and more consistent results because of software development.

Behn Heaven, which says, in his opinion, what separates El acoustics from the rest of the pack.

And so I guess I’ll start one thing I kind of wanted to point out now from our the system calibration workflow from the Live Sound Summit will kind of start with some of the more technical things that I think system engineers can appreciate. So the systems are designed there, musically voiced loud speakers. There’s there’s inherently more low end or the available resources is there. We provide tools for you to adapt low frequency to high frequency. So generally speaking, you’re going to have the ability to have a full range system that’s going to perform musically and that kind of that takes place throughout the entire product range.

So that’s an important thing for us. It’s an important thing for for our users and allows us to be able to say I want to have the same frequency response for the file system as I do for the main system and still be able to use our systems and have the same musical response. Or let’s say you’re doing a stadium show one day and then you’re doing a ballroom show the next day, that frequency response is going to stay the same no matter what what products are using.

So that’s important to us. Another thing I just spoke on is kind of the prediction side of things. So we’ve got a predictable output frequency response and activity is linear at all, operating sensitivities. So again, we’re taking into account the system operating at very, very low output and then going up to its maximum output and still performing the same without breaking apart or port distortion. I’m sure we’ve all heard subs sound like they’re farting or something like that.

So we try to try to minimize that and make our systems as linear as possible. And I think touring that’s I see that a lot. And kind of going back to the in one conversation and looking at smart and things like that is you see a lot of people that calibrate systems at very low spell’s because it’s comfortable. And then the system is operating at very, very high speeds and portions of the systems system can’t keep up with or I should say other band passes of the system or other systems can’t keep up in the entire system, starts to lose its linearity.

And that’s where customers are front of house mixers or people start to get disappointed with with the performance of our systems. So that’s really important to us. I think that’s a thing that separates us from other manufacturers for sure. OK, so a couple other things. Then we talked about frequency response. And I think in my in my capacity right now, one thing I pride myself with and I know our team prides ourself with, is listening to customers, listening to users, getting feedback from them, thinking about new features and kind of quicker ways of doing things or better ways of doing things and quickly and consistently updating and making improvements to our software, which is obviously easy.

Just download new updates and I’ll say on this and many other people that we do these updates about every three months. So if you’ve been out of the software ecosystem, our software ecosystem for three months, it’s best to download whatever’s latest and read the release notes and then also the hardware. You know what? What makes these systems easier to deploy for people? You know, what are features that people liked people don’t like and try to, you know, listen to our our users, listen to our customers and make make changes fit their needs.

So I spent a lot of time listening to a lot of time taking notes and trying to feed that into the into the R&D team. So, OK, OK, cool. Stagecraft says, how do they design their presets?

OK, we talked a little bit about this with the car to question kind of looking at input stimulus, but I think what’s important about this is I’m just going to kind of go through the first part and we talk about this a little bit and we talk about it like in some vision where we have our pink noise as our stimulus and then we’re going to take into account amplifier headroom and then kind of Kresse factor to account for transients. And then we’re going to kind of design backwards or what is the what are the frequency response goals?

What are the the sonic parameters, like acoustic parameters with the loud speaker? And then what are the power supply requirements of the amplifier? What are the you know, what kind of transient information we need to have at all frequencies and specify specify transducers, specify an enclosure that accomplish those things, and then even down to enter element angles, kind of thinking about what what can we do to have a smaller system that has more flexibility with with total curvature, so to speak, within a light source while maintaining good WCT criteria.

So kind of thinking about that and then thinking about trying to keep things simple, trying to keep maybe a handful of presets like we said we use for Khara, there’s carto is like car 70, car 90, car 110. If you’re going to use that as a fill car, fill preset. And those have different parameters, but there’s it’s easy to like load that. And a lot of touring people these days are actually just designing the system in sound vision and then just importing this directly into a network manager.

And that carries all the presets that you’ve specified for the different use cases right in. So you can load that to your network to try to keep it simple. And then obviously a critical listening. So take this out. Have a listen. I have the R&D team and the design team kind of make adjustments to The Presets, obviously try to stay within a latency quota to account for other kind of fiber filters and things like that that are going on to maintain good poller response and then going back and kind of thinking about, well, you know, what can we do to improve this and then come out with the best product, best foot forward as far as The Presets and then after release, then kind of getting feedback and if there’s any kind of changes or improvements.

And I mean, this kind of happens as technology improves and predictive and measurement capabilities improve and try to try to make things that are going to be better and release new presets not too frequently. But if there’s a thing that we can make it make improvements from a software push, then we’ll we’ll explore that.

So be Meiners has a question for you and we’ll see if you have anything to say about this, because it’s I feel like we may need some more information. But he says how to achieve tonal balance with smaller liner, a six to nine caras per side with three elements at one AMP channel. So smaller system and kind of the maximum number of elements per AMP channel, it sounds like. Do you want to say anything about how you tonal balance yet now?

Again, you’re somewhat limited with three elements and a line source, especially in this case, Kyra, it’s a pretty you’re kind of looking at a point source behavior, especially in the low frequency domain. There’s not a lot of activity control in that example. So what I would encourage somebody like this to do is to take advantage of in sound vision. If you go to Target Toolbox, there’s a a second band pass view that you can look at any kind of I like to recommend a low frequency band pass so then you can look at frequency response across the audience from one to ten K and at the same time look at distribution of frequency response at a lower range.

So like seventy to like two hundred fifty hertz. And again, I find myself designing systems like this for small deployments and it’s important to think, to look at those kind of things and think, you know, what can I do to make sure that high frequency stays consistent or predictable with low frequency? I would definitely recommend that. And I guess kind of going back to the question about what what sets our products apart from others is we want to look and design the best mechanical solution before we go into the world of adding electronic coloration to improve a problem that was could be fixed with a mechanical solution that allows us to look at that stuff in sound vision.

I think that second band is a super useful tool. So, OK, so Christian Frederick has a question. I know where he’s getting this from. So there’s a lot of great training videos on YouTube now from acoustics. And I remember and one of them, we learn that with our acoustics gain shadings big. No, no. And yet you can combine sometimes different boxes in the same array. And so Christian says if smaller boxes are used for down at the bottom of the array, won’t that produce the same problem as gain shading?

Hmm. Yes. So that’s that’s kind of taken into account in the R&D process where especially in the high frequency domain. We have a lot of interferences between these different wave guides, so what we want to do is design a preset that has a constant latency. And when you load, let’s say, for the case of Q1 to Q2, when you load that K2 preset, that preset has the same phase response as the K one preset out of the box.

Now, in the case of, let’s say, if you’re going to do car to car below Kawan or something like that, you need to make sure you load that car down one preset to to to make sure that that those interferences are predictable and it’s not going to cause any kind of steering or anomalies in the wavefront. So we’re and I think what’s important about this is we want to encourage the use of mixed arrays or at least in my designs, my designs and kind of what I what I find flea’s for touring and rental systems is essentially remember that as we get closer to the front of the room we’re getting there’s the proximity to the system is increasing.

So obviously in the high frequency domain, the system is going to have higher sensitivity or higher output at that position in the front. So naturally, what we can do is use a box that has less output capacity. So, again, that speaks to the idea of going from one that has a higher output to reduce the output of the system by just mechanically switching to a less powerful loudspeaker. That accomplishes the same thing that would I think people have would have a tendency to use gainsaying against shading to accomplish.

Now, there’s kind of a parallel conversation with this is what we want to do is when you get close to proximity to a system, a lot of times we don’t have a lot of control over ultralow frequencies, depending on the geometry of the line source. But in the high frequency domain, we can use FLIR circuiting or sorry for attenuation. That’s constant latency is accounted for in the preset latency to reduce Aspell output in the high frequency domain. So we want to be sure we’re using that.

And if you’re calculating, call it auto FFR. It will take into account array, geometry, audience geometry and atmospherics. It will prescribe a set of fiber filters to normalize or reduce these kind of spots in the coverage area that are caused by high frequency building up because of the mechanics of the line source.

OK, so Dan Barrett says, how many toddlers does he think he can take in a fight?

Well, you know, like I said, growing up in the Midwest, I played hockey as a kid. And that was one thing I kind of learned is a lot of those smaller guys can run right around you. And so probably not very many. I’m a pretty big guy and I feel like they’d have a pretty massive advantage over me. So not very many.

So Tiago FIRREA for you, Artiaga. So Tiago, in one of the person stinting questions about the Katou in the car in the K3 and Vic and I were chatting before we started rolling today and we’re not going to cover those questions because those are actually answered in a product release that’s coming out tomorrow. So by the time this interview comes out, that program release will already be up. So Tiago and the other person have the question about the K3. Check out the acoustics website, and you should be able to find the answer to your question.

Christopher Patrick DPO Viks had quite the career being a system engineer for such notable mixers as Scovel and Pooch. If it’s in within reason to venture outside of the brown box realm, I’d be curious to hear his opinions on some other risks he’s deployed. I’d say most curious was Onya as that stands out above others, considering the flexibility it offers in some terms of DSP process control. And I’ll just point out that I think if people are interested, if I’m remembering correctly, you can find a YouTube video of Robert Psychoville talking about the system and I’m guessing you were involved with this.

Am I saying that correctly?

There’s probably there’s probably Robert talking about it and me running around frantically, you know, calibrating the system hours before sound check or something. So there’s there’s probably some hilarious footage of me running around an arena with a bunch of microphones and. Yeah, exactly. But to his question, I think I think one of the more fundamental kind of things that I’ve learned through these processes of dealing with different manufacturers systems is to reach out to the manufacturer and immerse yourself in their recommended guidelines and ask them the hard questions as what do you think I should do?

Like what manufacturer should I do to optimize these systems or to deal with these kind of concerns I have or deployment questions.

They want you to be successful.

Exactly. And they’re nice people and they’re going to you’re going to take time. You need to make sure you allow time to, you know, plan and bounce designs off of them and bounce ideas and not to be defensive, not to be, you know, kind of disarm yourself as far as put your learning cap on when you’re when you’re around these people to absorb as much information. And I think if you kind of use their. Imitations, you’ll get the best results and you know, you’re talking about Onya and talking about systems I’ve used with Pooch, I think that was the same kind of thing where there was a lot of new technology that we were testing out for the first time.

And they had recommendations. And I tried to be patient and use the systems exactly how they recommend.

OK, Nicodemus says stereo versus mono. If the stereo image is mainly enjoyed by only a few people, of the many in a live event, could a single wide dispersion line or a provide more uniform coverage?

Yeah, so I think it’s a great question. I think I guess the technical jargon would be, are these correlated or dB correlated input inputs to the system? So what are we doing? Are we looking at like feeding like a paging system or it’s a mono and is it a stereo send or is it something more complex than that? Like an immersive system or LCR is a topic of conversation often. So I think that, yes, that’s a huge problem with Domoto.

It’s a huge problem with stereo that it’s not optimized for the populace of the audience. And so we need to think about that in deployment. I think, you know, I just kind of say LCR, for example, it’s important to kind of think about that kind of thing, to have as much overlap between all three of these these sources. So as many people as possible are experiencing the localization of how you have things panned in that’s in that field.

Now, I think one of the great features of immersive mixing or Lisa systems is that it accomplishes that a lot easier than having to deal on a bunch of different bustline and things like that. There’s a bunch of different Netco uses the term this kind of single wide dispersion line source. So what we’re doing when we’re deploying these systems is we’re using a variety of usually like five five line sources or seven sources or something to provide that consistent coverage and total balance on the horizontal domain.

And then all of those sources are essentially overlapping coverage. So you can place an object in that environment and you can move it and it’s not going to change tonal that balance or or level as you move it through the sound field. Cool. So I think that that’s that speaks to Elisa, but I think that it’s important to think about those kind of things. Also important to think about temporal localization. When you’re thinking about filesystems, I mean, just remember that there’s always a function of delay and level where your brain is going to localize the direction of what sources heard first.

OK, so it’s complicated thing even for dual mono and LCR systems to think about. You know what that what how that’s how the bus comes into the system. Yeah.

Do you have any unique or interesting pieces in your work bag that you could tell us about something that you think other people don’t have or don’t know about?

I mean, I think most touring people kind of know about this, but it’s true. Paul Rangefinder, that’s kind of a standard thing. I think that, you know, always the question comes up in a lot of our trainings and and obviously for tours and stuff when that resumes is, you know, how do I measure the room? How do I gather room dimensions and create a quick model? So I think a true POS is a good thing, especially if you you know, you already have a room model.

You just want to verify its accuracy. You know, it’s easy enough to do that. In addition, carry a small tripod to put that true pulse on. So I think those are all kind of things that are pretty small and pretty easy to fit into a backpack.

The the one where the like the camera. And so it has a little screens you can like in the daylight. You can see what you’re aiming at.

That’s like a like I think the like a series has that this is more of a range finder kind of hand-held thing. And see Laser Technology Incorporated is the company that builds it and they say optical laser. It’s not a red dot laser. So it works through most kind of fog conditions. And I think as it goes up to about three hundred meters, so it works well for dark arenas to stadiums, which when it’s the bright sun out and things like that.

So other things in the work bag that I think are are very acoustic centric. I carry a P one with me. The P one allows me to use in one to calibrate carry a couple of measurement mikes the right now you can plug for for measurement mikes into the front panel like Prix’s of the P1. But I usually carry a couple spares in case one gets attacked by a by a chair, Carter a forklift or something.

So what makes you have.

That’s, that’s right. Now I simcock seventy one fifties. They’re just, they’re affordable, they’re pretty accurate and again the quality of these microphones. But when we’re compiling these information, this information, we’re relying on a variety of different measurement positions to produce our average. So the more average results you have of the system, if one mic has slightly different frequency response from another within reason, because we have so much average and information to the statistic, information is better.

So. That’s the thing, and then the other thing is a little spell calibrated to make sure those mikes are working properly and they’re all running the same sensitivity. So we don’t have bias towards one data set in the data collection.

Vic, is there a book that you could share with us that’s been really helpful to you?

Oh, yeah, those are some interesting, interesting questions. I guess academically, I think one of the things that I kind of kind of changed my opinion years ago about designing these systems and thinking about optimization is it’s called The Complete Guide to High End Audio. And this is Robert Harly. And I think the focus on this is more kind of high fi systems. But I think that the important takeaway from high fi systems is you’re usually accomplishing more with less.

So there’s less in the signal flow. You’re using really, really high quality components. And that way we don’t have to rely on a bunch of widgets to improve the frequency response or improve the desired performance of the system, because we’ve picked portions of the system or segments of the drive system or signal flow with the best possible pieces and the least amount of coloration or face shift or attenuation or headroom issues and things like that. So I think that’s an important mindset.

And, you know, people you know, people think I think a lot of this stuff kind of gets forgotten about in commercial audio and tours and stuff. And I think that’s really, really important because you’re going to get the best results out of the system and you aren’t going to have to do a lot of upstream signal manipulation to get the results you want. Second book, I thought it was kind of a good one to put on here is called The Idea Factory, and it’s it’s by John Gaertner.

And it’s about Bell Labs in the early 20th century, kind of through the 70s and 80s when Ma Bell was broken apart. And this Bell Labs, they kind of wrote the book on a lot of what we deal with in audio networking and kind of our references as far as how decibels work and how we’ve defined these kind of studio references over the years that we’ve adopted into the sound reinforcement field. And I think it kind of puts I like to kind of think of a lot of the problems that we think are unique to sound reinforcement.

The phone company dealt with the same problems years ago, decades ago. So I think it’s a good kind of humbling story of reading, reading through and kind of an understanding where the concepts kind of came from. Another book that I kind of want to just bring up that I thought was really, really cool is failure is not an option. Kind of goes back to my space nerd things. And this is by Gene Krantz, and he was the NASA flight director during Mercury, Gemini and Apollo.

And he talks a lot in this book about building checklists and building redundancy systems into aerospace. No, no go, no go checklists, things like that. And I think that’s the mentality that we want to encourage and adopt for tourist applications. So that’s a good one is also, if you like, physics and aerospace stuff, it’s a good read, not to mention some crazy failure scenarios where they have to kind of move quick and make some decisions that could potentially equate to the life and death of a crew duct tape involved.

So, yeah, I think so. Yeah.

Yeah. Do you listen to any podcast?

I do, I, I do listen to a lot of pop to know which ones you have to listen to every time they come out.

Oh man. I got, I got a couple for you so I’m going to leave the political podcast aside for this discussion. But one of the ones that brings me great joy is a podcast called Switched On Pop. And what these guys do is they just dissect pop music or take a song or a genre and kind of unpack it and talk about why pop and what makes it what makes it interesting to listen to and kind of the evolution of the story and what it means as far as songwriting and and and so on from there.

So that’s a good one. And I also think that for a lot of this stuff is having a good understanding of musical instrumentation. And I think that’s a good place to kind of start thinking about arrangements and think about how that translates to how songs are recorded and how the public or the masses kind of perceives how a pop song should sound and thus how a system should be deployed for sound reinforcement.

Well, Vic, where’s the best place for people to follow your work?

I think the best place these days, you can definitely acoustics on our website, you can go on there and go to contact and find a picture of me and my email and shoot me an email and my phone numbers on there as well. I think you give me a call day or night and we. Yeah, oh, any time now I never sleep. But no, we try to I try to keep try to keep our our customers in any kind of interesting projects that we’re working on.

We definitely post on our social media in L.A., the best sound on Instagram and everything like that. So try to keep a steady flow of tushy in the pandemic times, positive and uplifting things kind of happening on a daily basis.

Well, I’m glad you said about people contacting you because we had so many kind of listener questions today that I think if, you know, if Vick didn’t answer the question the way you expected him to or there’s more information that you want or I didn’t ask it the way you wanted it, so you should reach out to him and then, you know, and then email me and let me know what he said, because I’d be interested to know as well, because I realized as soon as we get into the interview, this always happens.

I realize, like I think I know what this person wanted to know, but I’m not totally sure. And so I don’t really know if I’m steering the conversation in the right direction. So reach out to Vick. He’s a super nice guy and he has contacts on the website. So Vick Wagner, thank you so much for joining me on Sound Design Live.

Oh, it’s good to chat. I loved it. So glad to get the information out there and have this discussion with everybody.

Don’t Align Your Subwoofer to a Room Reflection

By Nathan Lively

Here’s a plan view of a sound system with two mains, a sub, and a measurement mic at a fixed location. If I asked you to align this system, would you prefer to start by muting the left side to align the right side to the sub or would you like to play both left and right together with the sub?

plan start

My guess is that you’d probably start by muting the left side to align the right main to the center sub, especially if you’re in a hurry and indoors where your measurement is prone to even more contamination than from just another loudspeaker. If so, you’d be in good company based on a few polls I ran.

What if I show you a prediction at 80 Hz with both left and right mains playing that reveals that the mic is in a power valley?

plan prediction 80Hz

You’d definitely want to mute that other side to do your alignment now because you know it’s going to contaminate the measurement and make your phase trace go crazy.

What if I rotate the room 90º and ask you to do the same alignment?

Would you change your strategy?

Nothing has changed so hopefully you would do exactly the same as before and mute one side to do your alignment.

What if I cut off half of the room and enable the bottom boundary?

Let’s make it look more like a section view.

section view 2

Everything is in the same place. Nothing has really changed for your alignment.

You might say, “Sure, I’d like to mute the other side, but that’s impossible.”

Maybe this dissonance is reflected in these polls. Or maybe I just didn’t phrase the question clearly.

Why is that?

Most of us have made our peace with the first scenario in plan view. You don’t necessarily need to align with both sides on because the left side will arrive with a slightly lower level and the right side will be slightly more dominant. So you mute the other loudspeaker and not think much of it.

If you rotate the room 90º the story doesn’t change except that house left in plan view has become the mirror image—living on the other side of the floor—in section view and you don’t have the luxury of turning it off. That’s the conflict. Your phase response becomes compromised and you never had the opportunity to prove to yourself what is was like in the absence of the mirror image.

Measured indoors, the phase trace can be hard to interpret or even so jagged that you think “Why bother?” or resort to a gratuitous amount of smoothing which is not the same as muting the mirror image.

This has made field tests of SubAligner in small rooms a real problem. I have done four tests in Canada, Spain, Greece, and Minnesota and they have all gone the same way. All of the measurement and listening tests are good until the mic goes to head-height. In the direct field it’s clear, but as soon as the room gets involved it falls apart.

This is a pretty big problem since I’m trying to sell a product that is supposed to create an audible result. If you can’t hear an improvement, why would you buy it?

SubAligner is a simple web app that uses a method of comparing relative distance offsets in main+sub alignments to pre-alignment values in its database. It short: it saves time on sub alignment.

I didn’t invent the method. I learned it from Merlijn van Veen. He got it from the L’Acoustics Preset Guide (Time alignment with geometric distance) and d&b Line Array Design along with his own field experience. The process is also described in the 2011 AES e-brief Time Alignment of Subwoofers in Large PA Systems.

From what I can tell the method is solid, but (and this a big BUT) you won’t always be able to hear or measure the results. It requires a leap of faith.

Fight the room

A floor bounce will cause a negative shift in the average phase measured at the microphone. Delay may be introduced to correct this local misalignment with unknown effects on the rest of the audience.

Here are two matching sources. With no boundaries enabled they create a perfect line of summation along the perpendicular bisector or median plane between the sources.

matched

If the floor is enabled the central power alley seems to be pushed up.

It is tempting to add delay to steer it down. Here the summation pattern has been outlined.

The entire shape is pivoted around the main speaker back into alignment so that the ground sub is properly delayed.

That should do it, right?

Damn it. I’m not sure if that’s better. There may be more of the audience in the blue color (lower level) now. It got better in one spot, but the rest of the audience has suffered.

Measuring LF indoors is scary

One challenge to alignment decisions is the excessive ripple encountered when measuring indoors, especially in smaller spaces.

Here’s a prediction of a subwoofer measurement using the previous example with 4 boundaries enabled. The more reflections, the more ripple, the harder the story is to read.

In this case the envelope of the measurement is still visible. You can see the trend and and indication of the original uncontaminated trace.

Let’s look at field data from a real room featuring two more walls. Here are measurements for a main+sub alignment that I attempted at a small church north of Minneapolis.

sub alignment messy
20% coherence blanking

Unless the audience is close enough where they can practically touch the subwoofer, most audience members will suffer from poor direct-to-reverberant ratios. Most audio professionals, myself included, would throw up their hands and say, “Forget about it.”

Average out the floor bounce

If measuring at a single location indoors is highly prone to error, how can better data be obtained?

Let’s measure at eight positions across the audience and average them together. Here’s the example from the beginning of the article with the addition of a standing height audience.

Here’s all 8 measurement of the main combined with its mirror image, plus the average.

Here’s what that average looks like compared to a solo on-axis measurement without the mirror image (ie. anechoic).

The mirror image’s delayed arrival time varies throughout the audience such that it averages out. The jaggedness is inversely proportional to the relative level offset between the main speaker and its mirror image.

If you are wondering why there seems to be more phase difference around 100Hz, it’s because those measurements made closer to the speakers have greater magnitude and a greater influence on the average. This is generally helpful since we’d like to average out the nulls of the comb filters. Here is an unweighted average for comparison. 

Field test

Ian Robertson from GerrAudio in Canada graciously agreed to test this with me.

The setup included eight Lina and a single 900-LFC.

After consulting the Sub Align calculator we could see that the phase span from front to back was very small (28º) and position eight was chosen for the alignment with SubAligner. (at this point I should probably apologize for titling my app SubAligner so similar to Merlijn’s calculator Sub Aligner or even Waves Sub Align plugin, but the URL was available so here we are)

Here’s are the measurements at position eight with the crossover region highlighted.

Here are the solo measurements of main and sub at each microphone position along with their respective averages.

Here are the averages alone.

I have to be honest that I wasn’t sure this would work, so I was really happy to see the alignment clearly visible, but also the similarilty with SubAligner’s predictions.

The first time we tried it, it didn’t work. My mistake was in calculating the coupling zone and alignment position in Sub Align based on a ground-plane height instead of head height, which has a much smaller phase span.

Step-by-step

Here’s is the method Ian and I used to test SubAligner.

I should first note that if you’re measuring outside away from boundaries you might not need to do any of this. These steps will be necessary indoors and anywhere where signal-to-noise ratio is low.

In order to find a global average free of local anomalies measurements must be balanced in level and phase. In level, in order to not tip the average towards one measurement with greater amplitude (eg. positions closer to the source). In phase, in order to not tip the phase trace too far in one direction or another.

XOVR position

Use the Sub Align calculator to find an alignment position in the center of the coupling zone. To do this, If the phase span is less than 240º, divide the phase span by two. If it is more than 240º, use 120º as the phase offset.

  • Example 1 – Alignment phase span 226º: Enter a max phase offset of 210/2 or 105º.
  • Example 2 – Alignment phase span 436º: Enter a max phase offset of 120º.

Measurement positions

Use at least eight positions distributed equally around the XOVR position. This may seem counter intuitive at first if the XOVR position is not near the center of the audience, but if there are an unequal number of measurements on one side then the average will favor that side and will appear to be mis-aligned. Of course, this is all much more critical with very large phase spans. If the phase span is 10º then the distribution is less critical.

Results indicate that a subset of eight measurements locations spread over the target audience area represents a rational solution to characterize the loudspeaker system response.

Optimum Measurement Locations for Large-Scale Loudspeaker System Tuning Based on First-Order Reflections Analysis

Most designs will have an asymmetrical relationship between the main, sub, and audience, and therefore require an asymmetrical placement of microphones.

main raised up to an acoustic center of 20ft

Level

Start at the closest position in order to avoid overloading the mic preamp. Use this position as the magnitude reference. At each new position reset the mic preamp to match this reference and reset the delay locator to the main. This will equalize magnitude and phase offset introduced by distance.

Back to the original question

When faced with an unknown number of mirror image reflections in a room, what do you do?

Do you rely on what you know to be true, or speculate on what might be true?

What you know to be true:

  1. Phase offset caused by distance offset is predictable and therefore alignable. Geometry tells us exactly where to align and what parts of the audience will be in the coupling zone and what areas will be in the cancellation zone.
  2. The pre-alignment values you created for this array were validated at the warehouse. You know they work.

What we can only speculate about:

  1. Attributes of the speaker’s mirror image living on the other side of the floor and every other wall.
  2. The validity of LF measurement data under poor D/R conditions.
  3. Where the null caused by floor bounce will end up at once the room is full of humans.

Back to Milaca. If we took that same system outside and measured on a calm day under near anechoic conditions I’m 95% positive we would get the data and see alignment. Inside where reflections dominate, suddenly the analyzer is showing me a different story. Unfortunately, it’s not a video game where you can turn off the walls. (the irony of Phase Invaders is not lost on me here)

Too much noise will render any measurement system ineffective. If it’s not working, try a different tool.

What has been your experience with trying to get actionable data indoors. Let me know!

14 online courses on live sound mixing, RF, and system tuning

By Nathan Lively

How do the 14 courses from Scott Adamson, Aleš Štefančič, Stephen Pavlik, and myself all fit together? We made a table to answer that for you.

They are grouped by teacher. Each teacher tends to focus on a topic of mixing, RF, or system calibration. Here’s a full-page view.

Please comment on this post with any questions.

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