To prevent feedback from your podium microphone and create the most natural sound, measure the sound system in Smaart, but use the podium mic as the measurement input.
Podium microphones can be a struggle. It’s nice that they are generally reliable and everyone knows how to use one, but they are also static. They don’t track anyone’s height or movements. This means wildly different levels for the sound engineer. While Darryn might stand at an ideal distance from the microphone, giving you sufficient gain before feedback, Pedro might stand or perform in a way that drives the sound system into feedback.
Luckily, the transfer function in Smaart can measure any two inputs against each other. Most commonly we use a reference input from the mix console and a measurement input from a measurement mic. But, if you switch the measurement input to the podium microphone then you can measure sound system bleed and room reflections entering the mic, then treat it with EQ.
I first heard the idea during my interview with Chris Leonard who saw it used on the presidential inauguration. Here’s how I have adapted it:
- Measure a transfer function using the vocal group as the measurement input and the console output as the reference input.
- Insert filters to equalize response.
- Adjust filters during soundcheck.
I like to take my reference input from the output of the mix console and before the system processor. If I’m doing the system processing in the console, I’ll tap the reference just before the system processing. Then, I’ll connect the monitor output from the console into an input on my audio interface and use that as the measurement input.
Now I can solo the podium microphone or the vocal subgroup to satisfy the transfer function.
Sometimes it can be really hard to get a lock with the delay locator. I usually need to search more than once before I can find a delay setting that will show actionable data. Coherence will be low because you are measuring a combination of energy from the back of the speakers plus lots of reflections.
Here’s a measurement from the podium of the last show I worked on.
Here’s the EQ I inserted to compensate.
Here is the post EQ measurement.
During soundcheck I adjusted the low shelf until it sounded natural. Here’s the result.
This gives me better gain before feedback on my podium mic and creates a great starting point for all of my vocal mic inputs.
I see a lot of possibilities for this measurement. Have you tried it yet? What were your results?