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[SoundMike]

One of my customers has a Saffire Pro 40 and we're getting strange results when using the BASS_DEVICE_NOSPEAKER flag in BASS_Init.

If BASS_Init is called with flags = 0 then we get the known 'problem' of outputs 3/4 and 5/6 being swapped, ie:
Front = PRO40 O/P's 1 & 2
Rear = PRO40 O/P's  5 & 6
Center/LFE = PRO40 O/P's 3 & 4
Rear center = PRO40 O/P's 7 & 8

However, if BASS_Init is called with flags = 4096 (BASS_DEVICE_NOSPEAKER) and separate audio files are played to each channel pair then the file played to 'Front' actually plays out of all 8 outputs and none of the other files play out of any of the outputs.

The flags used in the BASS_StreamCreateFile calls contain only the relevant BASS_SPEAKER... flag, eg
BASS_StreamCreateFile(BASSFALSE, "Chopper.mp3", 0, 0, BASS_SPEAKER_FRONT)

I'm only aware of this happening with the Saffire card. Anything I can do to sort this out?

[Ian @ un4seen]

Normally, when speaker flags are used or multi-channel stuff is played, BASS will give DirectSound a speaker arrangement to use via the "dwChannelMask", as described here...

   http://msdn.microsoft.com/en-us/windows/hardware/gg463006.aspx

But when the BASS_DEVICE_NOSPEAKER flag is enabled, BASS will use dwChannelMask=0. So I guess it is that that is causing trouble for the Saffire card. In that case, I think you will probably just have to leave out the BASS_DEVICE_NOSPEAKER flag and put up with the swapped output order.

What Windows version is being used? How many speakers is BASS detecting (see BASS_GetInfo), and is that correct? If it isn't correct, you could try using the BASS_DEVICE_CPSPEAKERS flag to have BASS get the speaker count from Window's control panel (pre-Vista).

[SoundMike]

Thanks for the link re dwChannelMask - that's useful info.

The customer is using Windows 7, and BASS_GetInfo is reporting 8 speakers, which is probably correct for the WDM driver, although I can't confirm that. The customer is using the latest driver.

So, as you say, the customer may have to put up with the swapped outputs. Although I may be able to reasonably easily swap the speaker settings in my program rather than use BASS_DEVICE_NOSPEAKER.