Wavfile44k

I will regret not taking him up on his offer to listen to his system. I believe he lived several blocks down the street from me. He was a pleasant and somewhat eccentric fellow. The likes of his generation will not pass this way again. Rest in peace David!

Some local places have klipsch speakers. The local rollerskating rink has wall-mounted Cornwalls which they play at ear splitting levels, Naaman's BBQ has the indoor-outdoor speakers (not sure which model), and my church used a pair of Heresy (probably 1970's) for main PA speakers for at least a couple of decades...

You might also check for external sources of interference such as cell phone or other cellular connected devices, anything that can emit RF interference (I had an old LED digital clock that would create noise), or it could be coming through the AC. You might move to a different power source. Anyway, things to try....

It sounds like digital leakage into the audio section. If you can turn off the bluetooth feature that might be the most likely culprit. They may have the antenna too close to an audio component. A design flaw for sure. Also, if you haven't already, run the bookshelves without the sub to make sure it's not leaking something into the system.