Re: No Audio V2.1 b1580
First and foremost, upgrade to latest Beta SDR-Radio V2, as 1580 is now "fairly way old" and superseded by the likes of Build 1608a, etc.
You may find the problem solved by doing so.
Other than that, make sure that the update to 1580 might not have soured the audio source selection in V2 irself...
...and one other thing that I personally saw here was that the audio in 1580 quit and I had to reselect the spectrum and frequency sampling in that area's dialog, and for me 1580 then began working fine again.
One other aspect is make sure that Windows itself still has the proper sound card / on-board audio chip-set or other source selected.
But DO upgrade to the latest Beta... the Beta's run just fine for 99.9% of us, even if marked "beta", and a lot of bug-lets have been solved.
Joe Rotello / Knoxville, TN / USA