my sound card changed gain automatically after 60-90 minutes.

[test_man]

I have my program which read sound input using built in labview VIs. It works fine for 60-90 minutes and then suddently my sound input values drops. It does not work evenif I exit and restart labview. But I did notice that while my program running if I change mic boost from on to off and then on again it seem to work. (It is always on and I don't change mic boost.

[Chris_Cilino]

Sheetal,

I assume by "my sound input values drops", you mean that the amplitude of your signal decreases. Is that correct? Do you notice this on other computers too? Has this always happened? Is the drop gradual or does it ocurr all at once? Post to let us know. Thanks!

Chris C

[test_man]

Yes, amplitude of the signal drops. Yes, I have notice same thing on other computers with same sound card. Sound blaster PCI512.

I am not sure if this has always happened but it happens now regularly.

Drop occur at once.

As I wrote before if I keep my program running and just change sound boost from on to off and then on again it works fine.

Is there any way to change boost programatically?

[Chris_Cilino]

Sheetal,

I'm wondering if there isn't something strange going on with your driver. Once LabVIEW is shut down, it releases all references to the hardware. One thing I'd be interested in seeing is if Windows Sound Recorder (Start>>Programs>>Entertainment) also registers a lower amplitude after that period of time (60 min). Also once the LabVIEW programming has been running and the amplitude decreases, what happens if you shut down LabVIEW and open Sound Recorder? Do you still see the lower amplitude?

Chris C

[test_man]

I still see lower amplitude even after I shutdown and restart labview. Same result with sound recorder.

Is there anyway to change boost programatically?

[Chris_Cilino]

Hey Sheetal,

I would look at msdn.com microsoft.com for the API to sound recorder. I'm sure it is just a matter of calling a dll.

Chris C