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play waveform output level


I have a Dakota PCI audio card ( ) and want to play a simple sine function with the express vi "play waveform". My problem is now, that whatever amplitude i set for the sine (from 0.1 V to 5 V), the output level is the same (always 3.6 Vrms). However, when I play a simple sine with Matlab, the output sound on my speaker changes with different amplitudes. Has anyone an idea, where the problem could be? The driver is properly installed as LabView plays all the signals i send to play waveform...

Thanks a lot in advance

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You can right-click on an Express VI and select 'Open Front Panel'. This will allow you to see how the Express VI works. In this case, it appears that the underlying VI(s) use the Normalize Waveform function which scales the Y from -1 to +1. This may be why your amplitude appears to be fixed in LabVIEW.

You can use the techniques you see inside the Express VI to create your own version of "play waveform" that leaves out the normalize step...

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Dear PhilipBrooks,


I know your post was long time ago, but I have the same problem now. I do not want the signal to be normalized. I did 'Open Front Panel', but there was no parameter or function for normalization visible. I'm using LabView2012.


Do you have any other idea or did I overlook something?



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