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So I have downloaded a backing track for guitar And wrote it into a cd player connected to my mixer (all independent from computer) and then I added the guitar on the mix, then I used a digital recorder to record what I play (boss BR-800) which is still not connected to PC and I recorded the whole playing and I was happy with the result, so I wrote it on a cd.

After when I got home I realised that the audio's volume was too low. When I tried to raise the volume with audacity I saw that the backing track distorted, but the guitar was just fine.

And now I am thinking if its possible to remove the backing track from the record and leave the guitar alone.

Anyone willing to help?

P.S if anyone want to take a listen to the recording here is a link (dont judge my playing, it sucks) https://drive.google.com/open?id=0Bz3Krsm113UecC03V2pwWmtIWmM

Dom
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Michael Selvesakis
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3 Answers3

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In general, it's true that you can't unmix audio that has been mixed - or at least, you need a very clever program (cleverer than Audacity!) to do so.

However, because you have the backing track separately, you may be able to take advantage of a processing trick involving phase inversion to get the guitar track on its own, if the backing track as recorded on the CD is a reasonably faithful copy of the track you downloaded. Unfortunately, you'll need to take some manual steps:

  • Load up your mix in one stereo track in audacity
  • In another stereo track in audacity, load up your backing track. Line it up exactly - sample-accurate, if you can - with the corresponding features of the mixed track.
  • Use Effect > Normalise... to get the volume of the backing track to match the backing track in the mix. (Look at a part of the mix where you're not playing guitar).
  • Use Effect > Invert to turn the waveform of the backing track upside down.

Now, when you play back, the backing track in your mix should be cancelled out by the upside-down copy, leaving only the guitar. You can then export that as a mixdown.

If anything here sounds confusing, google phase inversion to isolate vocals - you'll find some more descriptions of the technique.

Нет войне
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    this is the answer; especially if you have the backing track audio file and the backing track on the recording was "directly" recorded over (rather than out through speakers and back in through the microphone). It's always difficult to absolutely get rid of it 100%, but since here OP's really looking for volume reduction this will be perfect (and may even work much beyond that) – Some_Guy May 14 '17 at 20:50
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    I'll try the method above and I will tell you, its recorded over analog output not from microphones but the recording level is to low – Michael Selvesakis May 15 '17 at 04:20
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If you have the separate tracks (not mixed) available, you can simply amplify the tracks you need. If you only have the mixed version available as a single track, unfortunately you won't be able to isolate individual parts of the sound to amplify.

ayoon
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    I have the mixed track and the backing track which is part of the record I thought if its possible to make the program to understand which part to remove. – Michael Selvesakis May 14 '17 at 20:12
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You tell us the backing track is not only too loud relative to the guitar but distorted.

Write this attempt off as a failure. It's beyond rescue. There MIGHT be some way of modifing the balance, but if there's distortion as well, and this isn't an irreplacable historic recording, just leave it.

Have another session and get the levels right. Preferably set up a system where you're recording into a multi-track audio sequencer on your computer. Put the backing track on one pair of tracks, monitor it on headphones while recording to another track. Then mix at your leisure. I think you already have most of the necessary equipment.

Laurence
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