Adjust Electret Microphone Sensitivty

Thread Starter

chuco61

Joined Jan 21, 2015
49
I have a sound to light reactive display that works well. Im using an msgeq7 setup with an arduino.
Rather than line in audio, im using this microphone. It does create the reaction im looking for, although, there is no user adjustment like the vintage sound to light boxes of the 70s.

https://www.adafruit.com/product/1713

in order to add sensitivity control to the circuit, where would the best place be to wire a potentiometer to the microphone via Gain, Out or VDD?
https://www.amazon.com/gp/product/B07DHGQSBT/ref=ppx_yo_dt_b_asin_title_o06__o00_s02?ie=UTF8&psc=1

Schematic for the msgeq7 can be found here: https://www.sparkfun.com/datasheets/Components/General/MSGEQ7.pdf
 

Thread Starter

chuco61

Joined Jan 21, 2015
49
Ive tried all three options and am still getting reaction when no sound is pressent in the room. It's probably noise from the circuit in general, maybe the power supply.

Any thoughts on when decibels are very low that no lights activate - without getting into the code, I like the analog approach. That is why I wanted to add in the POT to have a little more control. I love the feel of the old school organ lights with the same functionality.
 

BobaMosfet

Joined Jul 1, 2009
1,108
The mic/amp you reference from adafruit has a gain-controlling amp. This will alter the sounds it presents to you. However, as an audio-reactive, you can still use it- but if you want frequency information you must use an FFT function on the sound-level returned in order to get frequencies.

Sensitivity is controlled by what gain level you want- 40, 50, or 60dB. Understand that all are very sensitive equating to between 10K bells, and 1M bells. Adafruit sheet tells you how to strap gain to adjust for each.
 

BobaMosfet

Joined Jul 1, 2009
1,108
Ive tried all three options and am still getting reaction when no sound is pressent in the room. It's probably noise from the circuit in general, maybe the power supply.

Any thoughts on when decibels are very low that no lights activate - without getting into the code, I like the analog approach. That is why I wanted to add in the POT to have a little more control. I love the feel of the old school organ lights with the same functionality.
When you say 'reaction', do you understand what you're saying? That mic is going to output 1.25V at zero sound, irregardless.
 

Thread Starter

chuco61

Joined Jan 21, 2015
49
Thanks, the msgeq7 takes the output of the MIC and breaks it up into 7 bands. I have it all figured out and working. I am simply trying to make adjustments to the signal between the microphone and the msgeq7.

Not opposed to using a combo of gain control via grounding, positive or unconnected though, but in tandem with a POT.
 

Thread Starter

chuco61

Joined Jan 21, 2015
49
When you say 'reaction', do you understand what you're saying? That mic is going to output 1.25V at zero sound, irregardless.
Reaction as-in the lights still activate when no sound is present. So are you implying that the 1.25v could be causing them to activate?
 
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