Debug constant clicking in audio stream

[csadams]

Hi, I'm setting up my first stream, and finally got it running thanks to some great help from folks on this forum:
WB6NDJ 146.8800 MHz ORCA Repeater Live Audio Feed

The audio currently has a constant clicking sound, with a 2-click pattern repeated at about 2x per second (2 Hz). Anytime there's actual audio content on the stream, the clicking goes away, and then fades back in a few seconds after the real audio stops.

I'm at a loss to debug this, as I'm not sure how to figure out where in the system it's coming from. Is it coming out of my radio/receiver? I don't think so because I can't hear it when I unplug the audio cable. Is it coming from the USB Audio adapter (this one), or its USB connection to my Raspberry Pi? I'm running DarkIce on a Raspberry Pi 3 Model B+... could it be coming from somewhere in the RPi, or the software? Or maybe it's interference introduced through the audio cable, USB cable, or power supply?

Anyone have tips for how I can check the system at each of these stages to see where the noise is coming from? Thanks in advance!

 

[csadams]

I finally figured out how to get the clicking to go away. I had to turn off the "Auto Gain Control" on my USB audio device. Took a long time to figure it out, since it turns out that once you select the "auto gain control" item on the alsamixer page, you have to press the "m" key to toggle it on/off. Unlike the other controls, it didn't respond to the arrow keys or space bar. Gah, frustrating, but glad it's fixed, and my stream is nice an quiet now, when there's no audio.