Creating and encoding pseudo surround sound files from stereo music recordings

Many years ago, I messed with the Hafler circuit, connecting rear speakers across the positive terminals of my front speakers, and quite enjoyed the effect (in classical music). I’m trying to work out whether I could render some of my current music files into a suitable format to play through an AV 5.1 receiver by creating AC3 files that utilise at least 4 of the available 6 channels. Having full-range speakers, I don’t need a sub-woofer/effects channel, and a centre channel would only mess up the existing stereo balance of the L&R mix.

A couple of questions, if I may.

  1. Am I right in thinking that I should import my existing stereo recording and then mix and render to a new track, before splitting the new track to mono, and inverting one of the two mono tracks before merging them again as a new mono track (discarding the intermediate tracks). That mono track is what I’d get from rear speaker(s) in a ‘Hafler’ setup (I think!). If I make that mono track a stereo pair, again, and apply an effect such as mda stereo (with suitable parameters), I now have pseudo stereo for a rear left & rear right pair, and all four channels are actually different, even though they were derived from just two.

Is that right, or have I gone wrong, already? I can use amplify to attenuate the rear signals, relative to the front signals, and if I can’t achieve the necessary distance to the rear speakers from my listening position, I can introduce a small time difference to the rear channels to compensate.

  1. I know that I can export the file as AC3 with 6 channels and play that file through hardware that supports 5.1 sound, but I don’t know how the channels need to be ordered/mapped and whether any particular naming convention is required from them to play as intended. My current experiment names them FL & FR (front left & right) and BL & BR (back left & right). I assume that my AC3 file should contain 6, but am very confused about mapping them in the advanced mixing options.

our audio video receiver should have various modes & “soundfields” that can make surround from stereo. The “matrix” mode should be similar to what you were doing.

Vocal Reduction and Isolation with the *Remove Center option is the same as connecting across the + terminals. You can then invert one of the new rear channels if you wish. That will give a feeling of a “wider” rear channel.

And you can add a little reverb and/or add some delay be adding a few milliseconds of silence to the beginning, etc.

It might make thing easier if you temporarily export that as a WAV file.

Then you can re-open the original, and then Import the rear channels to get 4 tracks.

I’ve done some experiments and there is the channel mapping in Audacity:
1= Left
2= Right
3= Center
4= LFE
5= Left Surround
6= Right Surround

I’ve never made a 4-channel file but if you have trouble you can make 2 silent tracks.

And you might want to make a test file… Record yourself saying “front-left” and “front-right”, or something like that.

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