Hello, I have very acute hearing and sat down in a room today with minimal ambient noise. I heard the strangest faint sound coming out of my MBP. It was sort of rhythmic and contained 4 or 5 mid octave notes repeating sporadically. It was actually sort of rhythmic at times, lol. Anyways, I've heard similar sounds come out of computers over the years, especially old laptops. Just wondering what causes it and if there's any reason for concern, thanks.