Does there exist an inexpensive USB audio interface that works on the R-Pi with a good quality mic-level input?
I have a no-name usb-audio dongle from ebay, super cheap at $5 but has a rather noisy and distorted input.
I've seen >$100 add-on board solutions using I2S which are I assume good. Is there anything in between?
Has anyone measured the DNR (dynamic range) of these audio parts?
Basically I'm looking for the cheapest thing that can give me a DNR of 70 dB or more on a microphone-level input.
Only one channel needed, not stereo. I do not need any kind of audio output.
I only need a low sample rate, for example 8 kHz or 16 kHz is fine.
It should be possible because the very cheap PS3 Eye camera has good quality audio (and 4 channels!) from its built-in mics, but it's a little bulky and I'd have to hack into it to connect my external mic-level signal.
Note: by "mic level" I'm thinking the full-scale signal would be about -50 dBV or 3 mV (rms).
So the input-referred noise should be 70 dB down from that, or 1 microvolt rms over a 4 kHz bandwidth.