I have a question about making an LED light up when sensing audio. Right now, I'm using Super-Regenerative receivers and testing various components of them. Using a signal generator, my audio speaker squeals, as it should, when on the right frequency. When it's not on the right frequency, I hear oscillations (white noise). I did a little research and found one circuit with a comparator and an op-amp. Basically, does anyone have any ideas on how to detect audio vs. white noise? As in, the signal gets quiet during white noise and is loud when on the right frequency. It's just highly annoying to myself and my classmates having it squeal all the time.