New; Is it possible to separate music from speech in 5.1?

[GbeTech]

Hi everyone.
I'm a musician. About a year ago I decided to build a career in soundtrack composing.

Mind you I have zero knowledge with video editing, but is there a way to separate music from speech and SFX? I want to keep the music out ONLY, so I can re-write it.
I understand 5.1 has 5 channels, so are the speech & SFX separated from the music?


By the way, it's enough to have only ONE channel with ONE type of sound (i.e. music), because then I can extract it and reverse-phase it to (partially) cancel out it's equivalent from the master audio track. It's not perfect but enough.

Thanks.

[DVDDoug]

You can't "un-mix" a song.

The whole idea of multitrack recording in the studio is that you can edit the tracks individually (or record the individual tracks separately and mix later). It would be great if you could record the whole band at once with one mic, and then adjust & edit everything separately, but it doesn't work that way.

Once the tracks are mixed down to 2 (or 6) channels, you can only edit the 2 (or 6 channels separately). If you've got a 5.1 mix, and the vocals are in the center channel, you can mute the center channel.

There is an "old trick" of subtracting left from right to remove the "center channel" vocals. Most audio editors have a vocal removal tool. But, this removes everything in the center (everything that's identical in both channels). It won't remove off-center or out-of-phase vocal-reverb, and it leaves you with a mono channel. It can be fun to play with, but it's rarely useful for serious audio production.

By the way, it's enough to have only ONE channel with ONE type of sound (i.e. music), because then I can extract it and reverse-phase it to (partially) cancel out it's equivalent from the master audio track.

If you have an exact a digitally exact copy of the vocal track, you can subtract it out perfectly. But if you have a separate vocal track, you probably already have the separate instrument tracks too... If you record yourself singing the same thing twice, or playing the same thing twice on an instrument, subtraction won't work at all! In that case there is no phase-correlation between the two tracks and, subtraction will sound exactly like addition. (It will sound like normal mixing).

[GbeTech]

Thanks for the reply.

There is an "old trick" of subtracting left from right to remove the "center channel" vocals. Most audio editors have a vocal removal tool. But, this removes everything in the center (everything that's identical in both channels). It won't remove off-center or out-of-phase vocal-reverb, and it leaves you with a mono channel. It can be fun to play with, but it's rarely useful for serious audio production.

I'm not quite sure I understood what you wrote but I know it sounds about right.
I'm not aiming for pro audio production, the only goal is to practice composition on a musicless movie.

So how do we do that old trick?

[DVDDoug]

So how do we do that old trick?

Aucacity is a FREE audio editor and it has a Vocal Removal effect.

In a normal 2-channel stereo recording, the vocals (plus the bass and other lead instruments) are the same in both channels. This creates the illusion of the vocalist being in the center. Subtracting left from right (or right from left) kills everything that's the same in both channels.

If your audio editor does not have a vocal removal effect, you can reverse the phase/polarity of one channel and mix the left & right channels together. Mixing is done by addition, so when you invert and mix (add) you are in-effect subtracting. (You can actually do the same thing with an analog mixer if your mixer has a phase-reversal switch).

The opposite (center only) is not so simple. But, there is a Winamp plug-in called DSP Centercut that can cut the "sides", and GoldWave ($50 USD) has a similar effect called Stereo Center.

[GbeTech]

Alright thanks. But my audio is split into 6 channels, can't we use that to our advantage? It must be easier that way, than the "flatted layers" of 2 channel stereo...