[scienceguy]

I use this card as part of a SDR (software defined receiver) system. Every
so often, I get an audio whine of sorts identified as close frequency
"spikes" of nearly equal amplitude across the frequency spectrum. This
isn't something external interferring with the SDR system because when I
turn off the SDR program and back on again, the whine/ spikes are gone.
This noise comes and goes, but always disappears when I turn the program off
and on again. I made a video he

http://www.youtube.com/watch?v=VC5e_GwIiPo

Be sure to watch full screen and in HD to see the spikes (which appear very
prominently in AM mode in the smaller frequency "waterfall" window).

I have also used this Audiophile card for audio work in the past. I think,
but I can't swear to it, that I have had the same thing happen sometimes
when trying to record or play back audio. Either a sound file will play
back distorted, or anything recorded will be distorted. I believe when I
switched from ASIO to MME or other driver would fix it, but I could then
later go back to ASIO without the distortion.... for a while.

Any thoughts on what this is and how to cure it would be appreciated. I am
using a Win XP SP 3, quad core, MSI MB with integrated sound card, but I
have and use the plug-in Audiophile card.

Thanks

[Nil]

On 18 Oct 2011, "scienceguy" wrote in
rec.audio.pro:

Any thoughts on what this is and how to cure it would be
appreciated. I am using a Win XP SP 3, quad core, MSI MB with
integrated sound card, but I have and use the plug-in Audiophile
card.

All I can say is that I've been using that same card for years and I've
never noticed that symptom.

[Arny Krueger[_4_]]

"scienceguy" wrote in message
...

I use this card as part of a SDR (software defined receiver) system.
Every so often, I get an audio whine of sorts identified as close
frequency "spikes" of nearly equal amplitude across the frequency
spectrum. This isn't something external interferring with the SDR system
because when I turn off the SDR program and back on again, the whine/
spikes are gone.

This noise comes and goes, but always disappears when I turn the program
off and on again. I made a video he

http://www.youtube.com/watch?v=VC5e_GwIiPo

This sounds very much like a problem with the SDR program, not the AP2496
audio interface.

I hypothesize that the SDR program has a logic error that causes the
production of these noises after some combination of events. Shutting the
program down not unexpectedly makes the noises go away. When you restart the
program, it is only a matter of time until this same combination of events
takes place again. When that happens, you again have the noises.

The AP2496 is a very common and relatively simple audio interface that has
nearly a decade of user experience with generally reliable operation behind
it.

Have you tried updating or regressing the version or change level of the SDR
program?