How does the voltage affect the operation of an electret capsule?

Question

I'm doing some field recordings with electret microphones. The manufacturer says they require a voltage between 2 and 10 volts. My Zoom H2N recorder delivers something around 2 to 3 volts I believe, which is at the lower range of the operation voltage range.

How does a higher voltage like 9 volts affect the recording behavior of the mic? Does a higher voltage enhance the signal-to-noise ratio (reducing it's self-noise) and increase the sensitivity for quiet sounds in nature?

I've heard that a higher voltage would make the mic more tolerant towards loud sounds but less sensitive for quiet sounds, so I'm a bit confused wether or not I should get a preamp.

Answer 1

I had the same question when i started to research electrets for My mobile setups. The answer isn't fully straightforward as it will change slightly depending on the specific capsule.

My experiences and info I have collected: In general the voltage isn't very critical unless it's way below what the specs say. Noise wont change that much but sensitivity and distortion will get worse at lower voltages (especially at low frequencies). Distortion at high SPL WILL change depending on voltage however, again especially at low frequencies.

Also bear in mind that most electrets are omni and have at times to much (Extreme) LF reproduction. So adding a ANALOG filter ahead of the recorder is often beneficial. Pip power is not always enough for Loud sounds with lots of lf content. So using a external power supply box delivering a voltage close to the upper range if the spec with some gentle LF roll off filtering will make most recordings sound better.

I won't promise that all the above is fully correct but it's built on my experiences of using electrets.

Good luck!