sound amplitude

[DavidT]

Hello everyone, 
I'm having trouble recording a sound file using LabView. I'm using a 3rd Party sound card (RME HDSPe RayDat) which is a 72ch audio card.  
The way windows detects the card is Device 1 =  Ch 1 + 2, Device 2 = Ch3 + 4, etc...

I have just tried to use the "Continous Sound Input.vi" and selected Dev1 to record on channels 1 and 2. If I record using single channel (1ch), my measurement seems correct. However, when i try to record from two channels (2ch), my signal on Ch1 is doubled in amplitude, and there is no signal on Ch2.

Ultimately, I would like to have a single microphone connected to each channel and be able to analyse each channel individually. 

Can anyone explain why this may be happening?  

Thanks,
David 

[kekin]

First try using SOUND RECORD express VI. If thing does not work then look for driver update or try changing the DEVICE derive settings.

Please post ur VI & screen shot of device manager showing channels.

I tried using express VI & it works fine for both the channels. Then simply convert express VI into source code of LABVIEW.

Hope this helps.

[DavidT]

Unfortunately, using the express VI still have the same problem where 1ch amplitude is not the same as 2ch amplitude. Attached is a screen capture of the devices available. 

[kekin]

Provide the screen shot of recorded audio i.e.preview.

[DavidT]

Previews attached.

[kekin]

The images shows too much nosie. can you do one thing. Use function generator to outout two sine waves of  different freq & amplitude and apply it as input to CH-1 & CH-2. Then give me the preview of EXPRESS vi. Can you please post the datasheet of sound card that u are using. It will be more helpful.

[DavidT]

This is the spec sheet for the soundcard. http://www.rme-audio.de/en_products_hdspe_raydat.php

The microphone is connected to a sound level calibrator (piston mic )running 94dB at 1kHz which we use as a calibrated signal.

I'll see if i can wire up something but it wont be that easy to do at the moment. 

Thanks,
David