If I set my computer mic to record into audacity, and talk, have some low volume music on, and bustle about somewhat noisily, and then clap my hands at various times, the corresponding spikes in the audacity waveform are unmistakable (if I drew a horizontal line across the whole waveform, and consider breaching that line a "clap detected", that would be accurate enough for my purposes).
I've hooked this up to a pair of small headphones, and it appears to "make the quiet loud, and make the loud quiet" (random scratchings from around the room feel like they're scratching your eardrums, while a "clap" feels muffled). This makes me think it's a bad candidate as a foundation for my clap detection.
I have not attached it to an oscilloscope, because I don't have one, and
I haven't attached it to a computer because I was told it couldn't output the power to do so, and
I haven't attached it to an arduino because I was told it doesn't output in the correct voltage range,
so I'm just going off "how it sounded".
I'm thinking of next trying this, but it seems to be a very similar amplifier (MAX9814 vs MAX9812L), so I'm not sure why it would be different (if the only difference between the two is ability to adjust gain, then I don't want to waste my time).
Another thing I noticed in the NOYITO description is it has a "built-in low noise microphone bias"- is this what I was hearing from the NACRO ("quiet->loud, loud->quiet")? Or is that referring to "low electrical noise"?
At the end of the day, I want a mic + preamp that doesn't try to do any noise modification for the comfort of human listening- I'd prefer if a "clap" were to just "clip" the wave in some detectable-by-arduino-input-pin sort of way.
I've also tried these, and have had trouble setting them to a threshhold that is broken by a clap, but not by moderate talking, which makes me think there's some similar kind of noise modification (either intentional or not) going on (or maybe the timing of the large clap-spike on audacity is significantly faster than the sample rate capable by this mic?)
The fallback I have is to use a pi with a decent computer mic, and then just do as I suggested in the opening sentence: detect when the waveform breaches some threshhold.
I'm wondering if these thoughts seem on-track, or if there's some simple arduino preamp/mic setup that would more appropriately fit my needs.