So I've picked up a Cybiko after having owned one some 20 years ago. I'm working on a project utilizing it, but have noticed something... I have an SDR, and have been using it to gather up information on the RF since I'm going to use the Cybiko RF to do some other radio related things. While I was using my spectrum analyzer I noticed a few frequencies that only appeared to paint my waterfall when the Cybiko was on. One of them, specifically around 913837500hz I noticed something extremely interesting. When FM demodulated, the Cybiko appears to output all Cybiko sound on this frequency, all the way from the time the device boots, even with the onboard sound muted. It's strange, and I don't see it being a side effect of anything, so it appears as if it was designed that way.