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I have a ICS-40181 MEMS mic and want to do basic spectral analysis using the popular MSGEQ7 chip for the purpose of a sound reactive project.

Can I simply connect one into the other (with cap/res as directed) or do I need an amp between them? Usually the MSGEQ7 takes regular line-level audio. How do I know this based on gain etc?

Math Keeps Me Busy
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Glebbb
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  • I don't have a scientific answer for you, somebody else might give that. But my gut feeling is that with with 1MOhm input impedance you can simply go ahead, connect them (via RC calculated per formula in MEMs datasheet) and see what happens. – Maple Jun 12 '18 at 06:14
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    It beats me why they called the MSG chip a graphic equalizer - it ain't. – Andy aka Jun 12 '18 at 08:46
  • Maybe because when people hear "equalizer" they don't think of boring bandpass filters but rather of flashy blinking displays? – Maple Jun 12 '18 at 10:57

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It depends on the levels you're measuring. If they're in the 1Pa (94dB SPL, business meeting) range, your output levels will be in the 100-200mV range max. In that case, you might want some gain. 10Pa (114dB SPL, busy urban intersection) would get you near full scale.

Cristobol Polychronopolis
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  • I agree that you must scream into the MEMS mic close to your mouth to get a line level from it. I also agree than the 7-bands peak detecting IC will not show actual levels, it shows only peaks. An obsolete LM3915 shows 30dB of actual levels per band. – Audioguru Mar 06 '21 at 17:30