Measuring how "non-noisy" a sound signal is Given a sound clip (whose source is an FM radio signal) I'd like to measure how different from background noise (the "in-between channels" noise) the sound clip is, so that I can compare the "non-noisiness" (and thus the quality) of two radio signals. Is there a good way to do this?
If the noise is (close to) stationary, you could use one of the many noise-floor estimation methods to get an estimate of the noise power and, consequently, of the SNR. Search for "noise floor estimation" and "noise floor tracking". You'll find a lot of publications and patents.