Why Do I Get 4 Tracks When I Import A Stereo Wav File?

I am using Audacity 2.0.5 and running it on a new HP desktop with a Windows 8.1, 64 bit OS.

While I have been using Audacity for about a year to convert stereo reel to reel recordings, I still realize that I am a newbie in regards to this application. I recently was given some .wav files of some 1970’s radio shows that I have been importing, editing and saving to CDR.

When I did this with the first file, I noticed that I ended up with four separate files labeled right channel, left channel, mono and mono. One of the mono channel wave patterns appears nearly identical to either the right or left channel(?) in signature and amplitude.

Going to the online user manual I understood that for the imported right and left channels, I simply needed to use the dropdown on the upper channel to merge them into a stereo pair. But without finding any other directions in the manual, I could only think to delete the other two mono channels before proceeding with editing.

The additional subtlety here is that these recordings are of broadcasts that were SQ quadraphonic matrix encoded, which are composed of four channels. My assumption here is that Audacity should not have a decoding function like Adobe Audition, that is automatically separating out the four encoded channels.

So, is there any chance that by deleting these 2 mono tracks, that I am ‘neutering’ my intended outcome? Does anyone have any knowledge/experience with this situation? I would appreciate any direction you can give on this.

It would appear that the file was not a “stereo” file but a “4 channel surround sound” file.

The usual channel mapping for quadrophonic sound is:
Channel 1: Front Left
Channel 2: Front Right
Channel 3: Rear Left
Channel 4: Rear Right

More information about multi-channel sounds: Surround sound - Wikipedia

I’m not sure of the “correct” way to convert 4 channel quadrophonic to 2 channel stereo, but if you don’t want to totally discard the audio from the two rear channels you could try setting channels 3 and 4 to Left and Right respectively, then use the track “Gain” sliders (Audacity Manual) to adjust the proportion of Front : Rear for left and right. Note that if you leave all of the gain sliders at 0 dB, then the addition of the “rear” channels to the “front” channels will probably cause the mix to be too loud and “clip” (distort), so watch the playback meters to ensure that the mix remains under 0 dB.

My assumption here is that Audacity should not have a decoding function like Adobe Audition, that is automatically separating out the four encoded channels.

That’s correct. The person who recorded them had an SQ decoder and they gave you a 4-channel WAV file. So at this point it’s no longer SQ encoded and SQ isn’t relevant (except for what the decoding has done to the files :wink: ).

If you want stereo, I’m not sure if you’ll get better results by throwing-away the rear channels or mixing the rear with the front. I think you’d have to try it both ways and decide which sounds best. SQ didn’t have a lot of front-rear separation, so you might not notice that much difference, but there were “logic decoders” that exaggerated separation.

SQ is similar to Dolby Pro Logic where the rear channels are “phase encoded” into 2-channel stereo, except Dolby Surround has left a front-center channel.

I think you’d need an SQ encoder to properly re-combine the front & rear to get back the exact original recording (they way it would have sounded if the original SQ record was played on a regular 2-channel stereo).

If you have a home theater system, you might want to retain the rear channels.

But, the issue is format… The most-standardized surround formats would be DVD (Dolby Digital or DTS) or Blu-Ray (Several surround-sound format options), but that would require DVD or Blu-Ray Authoring software and a learning curve if you’ve never created a DVD or Blu-Ray disc. If you are playing the files from a computer, AAC and WAV can also support multi-channel audio.