Audio file creation

[Tim-M]

Thanks for the explaination... sounds like an excellent idea.  Why not make use of the eight channels already in front of you!

Tim

[JonnyMac]

My friend, Peter Montgomery (www.socalhaunts.com), has a cool custom app that lets him play any audio file through any speaker in his system.  He uses it will his animation controller to move sound around his yard -- it's very cool, but probably above my programming skills (I think it uses DirectX).

[JonnyMac]

Great news, Jeff: the latest Audacity beta supports multi-channel output!  I'm surprised this isn't touted in their features list.

In the Edit\Preferences dialog you have select "Use custom mix" form the Import/Export page.  When exporting the multi-channel mix you have to click on a track (it gets a red outline), then click on the output channel (also gets a red outline).  You can click on the track and output channels again to de-select them, or click on the link between the two to remove it (sounds harder than it is).

I used the six-channel demo files from Microsoft and moved the output tracks around -- when I reopened the new file it seemed to work.  Give it a try; I don't have 5.1 audio on my PC so I can't test.

[JonnyMac]

As a quick test I loaded up six mono files and did the same export -- none were assigned to left or right output in the project (via the track header).  On doing the export the program assigns the track number to the channel number in the WAV file, like this:



By clicking on the connections between track name and output channel you can delete them.  Then you can re-assign by clicking on the track name, then the output channel where it goes.  In this image you can see that I swapped what should be the left and right channels:



This mixing panel remembers one track name and one channel name, so you'll want to make sure you have everything de-selected before assigning a new track to an new channel, otherwise you'll get extra connections (which can be deleted by checking on them).

Now I've got to ge see if I can find a simple 5.1 or 7.1 system for my laptop so I can demo this in my Audacity class at MHC!

[davisgraveyard]

Fantastic News! 

You might want to be a little carefull using channel 4 which is normally the subwoofer.  I'm not sure if your sound driver will try filter out the high frequencies when playing the channel. 

I tried creating a file and when I try to play it on my 7.1 system Media Player says it can't find the codec?   I am just exporting to a 16bit PCM WAV file?

[JonnyMac]

I can't play the files in anything but stereo, so I'm not sure.  You may want to set the output to 32-bit float as that's what the Microsoft demo files opened up as.

[davisgraveyard]

Finally getting back to this topic.  I found out why some of my test WAV files wouldn't play.  You can't just arbitrarily choose the number of channels you want to have in the WAV file.   It must be 2,4,6, or 8.  Even if you just want your sound to come out just the Center Channel you must move the slider to 6 or 8 when creating the WAV file otherwise the player doesn't know what it is.

I have created several WAV files with 3-4 tracks of sound in them each playing out a specific channel.  Works GREAT!   I am using a slimline PC with a 7.1 sound card.   Once I copy the WAV file to the computer I just use Windows Media Player and play the file in a loop.  THe separate sound effects come out their respective speakers. .

Now I can use the PC to drive my sound effects instead of a bunch of amps and CD players.

Jeff
www.davisgraveyard.com