I noticed with either external powered speakers or headphones connected to the Maestro there is a significant low level noise underneath the receive audio. It seems to be independent of AF gain setting and is easiest to hear if AF gain is set to 0, although it is also noticeable when listening for low level CW signals. It is not present with the same powered speakers connected directly to the radio. Is this an artifact of the audio stream compression. This is with the Maestro connected via a 5GHz wireless link with 5 green bars of signal quality.