Windows & Multiple Audio Outputs

Black Hole

May contain traces of nut
Does anyone know if it is possible to DJ on a Windows PC using the headphone output for the main feed to the amp and at the same time use Bluetooth headphones to cue up the next track?
 

gomezz

Well-Known Member
Probably depends on the sound card the PC has and you would need to check the specs of each one to see if it does what you want.
 
OP
Black Hole

Black Hole

May contain traces of nut
What's that got to do with a sound card? The (notebook) PC has an audio output in the form of a headphone socket, and it also has Bluetooth which can (presumably) connect through to Bluetooth headphones. I think it's more to do with whether the OS is capable of separating the audio outputs and sending a particular program's output stream to a specific output independent of other audio sources.

I want to know whether anyone has tried this and made it work, or failed so I don't waste time trying.
 
OP
Black Hole

Black Hole

May contain traces of nut
In case anyone else wants to know (Win 7 Home Premium 64-bit):

The objective is to have audio on the main PC output, and at the same time to be able to preview and cue up another track using Bluetooth headphones. Specialist DJ software seems to use the side channels on 5.1 to provide an independent preview feed.

I spent a couple of days thinking about this and googling, and somebody (from Microsoft) on the Microsoft forum seemed to think it wasn't possible "by design", and then I stumbled on Virtual Audio Cable which promised to add as many channels to the available audio destinations list as necessary. So I figured that was what I needed, downloaded a trial version (which adds an audible watermark to the data stream every few seconds), and sure enough there appeared two "virtual cables" in the output list I could direct audio to.

But that's as far as the audio got, there seems to be no settings in the VAC control panel to direct the streams anywhere specific, so then I had to download Audio Repeater which required no installation but created a route (per instance) to direct an existing audio stream to another stream or device (the trial version injects periodic silences). Bingo. Two instances of VLC: VLC1 > VAC(1) > AR1 > Primary Audio; VLC2 > VAC(2) > AR2 > Bluetooth audio renderer profile. VAC $35, AR £18. Hmm.

Except the solution had been staring me in the face all along. VAC may be useful for making a program that can only normally capture input from a physical device take a feed from a program that can normally only output to a physical device, but all I wanted was to direct specific instances of VLC to specific physical devices... and that's available on the VLC toolbar under Audio... Audio Devices! The only catch is that unless the Bluetooth headphones are powered up and linked, and the Audio Renderer Profile (A2DP) enabled in the configuration, at the time VLC is started up, the option does not appear in the devices list.

(Don't use Bluetooth Hands-free Profile - the sound quality is awful!)

(If you can't start more than one instance of VLC, look on the Tools.. Preferences menu and make sure the "allow only one instance" and "use only one instance when started from file manager" options are unticked.)

The reason the Microsoft person probably thought this isn't possible may be due to cross-purposes - the discussion I was reading may have been about separating the front and rear audio from a PC motherboard (implemented as the built-in speakers and headphone socket on a notebook). This is different; the Bluetooth provides a completely separate hardware system and set of drivers.

It should also be possible to separately route audio to the HDMI, which should appear as another hardware device in the destination list when there is something suitable connected. That would make three independent playbacks possible! My HDMI matrix switch has an audio pick-off which I use to drive the speakers either side of the projector screen - so watch this space for when I try the experiment!
 
OP
Black Hole

Black Hole

May contain traces of nut
It should also be possible to separately route audio to the HDMI, which should appear as another hardware device in the destination list when there is something suitable connected. That would make three independent playbacks possible! My HDMI matrix switch has an audio pick-off which I use to drive the speakers either side of the projector screen - so watch this space for when I try the experiment!
Yup, it works.
 
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