I changed duplex=0 to duplex=1 in usbradio.cfg That seemed to clean up the audio. Turning on the DSP, must make the audio slightly more bassy. Thanks all 73 Jim W7RY From: Kevin Custer Sent: Tuesday, October 09, 2012 6:35 PM To: Jim W7RY Cc: app_rpt-users@ohnosec.org Subject: Re: [App_rpt-users] USB Radio Commands I reconstructed the following query, as the answer to your question was already in the text you pasted. Kevin So if this setting txprelim=yes is: TX audio processing. Options: (no,yes). Choosing yes turns on transmitter preemphasis and peak limiting, along with a lowpass filter. The yes option is used when driving an FM transmitter directly by injecting audio right into the modulator. ------------------------------------------- What is the setting? txlimonly=no The no option provides audio which should be injected into the microphone input of the transmitter or at some point in the transmitter' speech amplifier before preemphasis, and limiting.