Volume unstable with SPDIF in and out.

[jay1103]

So I'm having issues with with the volume control being stable. I have SPDIF into my Pro from my TV. I have SPDIF out to my soundbar. Was working fine before adding the WIIM pro. If I lock the volume in the app to max and use the soundbar volume control it's fine. When I unlock it, leave the soundbar volume alone and change it from the app It plays fine for a minute or two then gets really quiet, a few seconds later it gets really loud, etc. Really frustrating. Any ideas? BTW: I also have WIIM mini. If I group them together the mini seems to play at a stable volume, although a little out of sync. Thanks in advance!