Attenuator for mic input

Tim Wescott · 2016-10-10T20:15:09+00:00

Slightly basic for this group, but also slightly audiophool, so I figured I'd ask here anyway. I've got an electret lapel mic that I'm using with my smart phone for making videos. It's pretty good, but it's hot enough that the audio bars on the phone are showing red on audio peaks. I'd like to try toning it down in electric-land so that things aren't clipped going into the phone. So -- is there a way to attenuate the audio coming out of an electret in a way that doesn't appreciably cut power to the microphone, while retaining the audio quality (which I like)? I suppose I could make a little battery-powered box that completely isolates innies and outies, but at this point I'd be MUCH happier if the job could be done satisfactorily with some network of resistors and caps, with one variable element to change the volume -- or even a fixed network, since I just want to get things into the phone's happy range and plan on adjusting things more in the video editor. -- Tim Wescott Wescott Design Services I'm looking for work -- see my website!

Oct 10, 2016 22 Replies

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Lasse Langwadt Christensen 9 years ago

Den onsdag den 12. oktober 2016 kl. 18.58.59 UTC+2 skrev Jim Thompson:

the bias resistor and coupling cap is internal to the phone

so afaics the only possibility is a load in parallel with the capsule

-Lasse

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Jasen Betts 9 years ago

measure what you can, then guess, they're all fairly similar.

This email has not been checked by half-arsed antivirus software

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Michael A. Terrell 9 years ago

I put 1N4007 diodes across the 25V speaker line at Microdyne. The closest speaker was at the far end of the facility from the amp, (~500') so it clipped quite nicely. ;-)

Never piss off an Engineer! They don't get mad. They don't get even. They go for over unity! ;-)

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