There is some kind of noise interference--every few seconds when listening (and watching TV).
I have my Roku/TCL/TV connected to a surround system. For weeks, I have been hearing this odd-sounding interference while watching "Direct Stream" channels. This is a TLC 55" TV with a built-in Roku. My first test was to turn off the surround system, and turn up the volume on the TCL--same noise--every few seconds--it sounds similar to a fart (sorry--but it does). I went into another room that has a external Roku and tuned to the same channel--but no interference. And then to the back bedroom to check its external Roku--there was no interference there.