Does lvsound2 support more than 2 channels?

[Tony Dal Molin]

I am attempting to play a multichannel WAV file through my PC audio system. It does not appear that the Sound Output Write VI supports more than 2 channels. Is this true?  Do I have to write a VI to interface directly with the sound driver DLL? Seems like a lot of other people must have already run into this problem.

[Joe_Guo]

you can use activex version of windows media player (WMP) to play the multichannel wave file. the activeX contol is already available on your machine so no other downloads are needed. it is quite easy to use wmp.

-Joe

[Tyler]

Tony,

           You are correct in your assumption. The Sound VIs in LabVIEW can only communicate with 2 channels. If you did want to have better channel count, for say a 5.1 system, you would have to call external code. I would like to know what you are trying to do because almost every sound (with exception of movies and video games) are 2 channels. Let me know I'm interested.

Tyler H

National Instruments

[Tony Dal Molin]

Hi Tyler,

Contrary to my original post and the posted responses, I have discovered that lvsound2 does support more than 2 channels.  An examination of the RIFF header data has verified this, though I have also discovered an error in NI's implementation of the multichannel extensions.  Nevertheless, I can proceed with my development work which, as you noted, is involved in Surround Sound applications.  From NI's standpoint, I would suggest that you rethink your position that audio is two channel - six is pretty much the norm and eight is quite common.  I have even seen a 22.2 system demonstrated!

Tony D.

[Tyler]

Tony,

[Tyler]

Tony,

[Tyler]

Again sorry for the errous post.

Tony,

I was wondering how you were able to see that our sound VIs supported more than 2 channels. I looked through all the documentation and knowledge bases on the issue and wasn't able to find anything contrary to the 2 channels. You mentioned something about a RIFF file. I know I am not a sound engineer so can you tell me what that is, where you found it, and how you saw that it supported more than the 2 channels? Also if you could tell me how you saw the implementation for multiple channels was incorrect, I could create a suggestion or a corrective action to get this fixed/implemented. Thanks. Hope to hear back from you soon.

Tyler H.

[Joe_Guo]

Wave format is a subset of RIFF format. you can see more details here.

-Joe

[AdamKemp]

Tony: Yes, the LabVIEW sound API should support more than two channels. I will try to see that the documentation is updated to make this more clear.

Could you tell me more about the problems you're having with multichannel sound IO?

[IBAH]

Hi Adam,

I'm also using the new LV8.0 sound API as a 'DAQ demo device' (e.g. SoundIn:4472 SoundOut:6733 ), to get some limited demo versions of our software running, without having a customer to install NI-DAQ on his system.

I have more than one sound board in my system and need to enumerate them. A possible customer may even have more boards in his system.
There are some function prototypes in lvsound2.dll which seem to allready address  this issue, but I don't find the header file for this dll.

Specifically I would need the function prototypes for

- SoundNumDevices
- SoundDeviceInfo (read back # of I/O channels)
- SoundDiagnosis
- SOVolume (or anything like it, to adress the mixer api )

to call the NI-LVSound2.DLL properly.

Can you please provide the header file of this dll and the updated documentation?

Yours sincerely,
Andreas