Sound Card Loopback

[grubworm]

How do I control the line in-to-out loopback on a PC soundcard/Windows mixer?  Is there a .dll I can control with a library function?
Thanks

[wiebe@CARYA]

You probably need to use DirectSound, if it's possible. I'd look for a .net wrapper first if I had to use DirectSound.

[TristanMayne]

Programmatically Control the PC Volume in LabVIEW

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000kHFKSA2&l=en-US

Does this answer your question?

[grubworm]

Hey thanks.  I didn't know which dll it was.  Still a bit of work to do researching the function etc.  What's the point of the for loops in your vi?

[RavensFan]

Please mark the actual message that gave you the solution, not your "thank you" message.

[wiebe@CARYA · Accepted solution]

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@grubworm wrote:

Hey thanks.  I didn't know which dll it was. 

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As far as I can tell. that example will only change the volume. It will not give you a loopback.

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@grubworm wrote:

What's the point of the for loops in your vi?

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100X to get from x to 0, or from x to 100. As far as I can tell, you're basically pressing the volume button 100 times.

You can always acquire the sound from an input, and play it back to an output. In a while loop, that will give you a loopback, but there will be a latency. Using DirectSound the latency will be smaller, if it is in fact capable of doing it (I don't know).

[grubworm]

Thanks.  Yea I recreated it and got it to do mute or volume up.  I started reading some of the microsoft api docs but the info i'm looking for is buried deep.  It's a start, so...