isolating vocals

[dentos]

hey there, I'm aware that by phase reversing one channel of a stereo signal you can cancel out anything panned centrally in the mix... is it possible to do the reverse - ie: phase cancel the anything NOT panned centrally so only leaving vocals and whatever else happens to be in the centre of the mix?

[Brian]

Short answer, no. Long answer, still no and removing the vocals doesn't really work that well. It will only work if...

 

1) Vocals are dead centre.

2) Vocals are recorded dry (ie no FX) - FX are usually stereo or pseudo stereo so the vocal cancel but you're left with the remains of the FX.

 

I guess it works OK for a cheapo sing-along.

[James]

Well if you wanted to do that it would be difficult to do live and I can't think that it would be very effective.

 

1 Take L and add the inverted R to give you M

 

2 Invert M and add that to L

 

3 Invert M and add that to R

 

does this make sence?

 

James

[dentos]

thanks a lot guys I'll have a fiddle and hopefully it's all good... is M a mono signal then?

[James]

Yes.

[Guest lightnix]

I recall hearing of a thing called a "Comb Filter" which could be used for removing vocals. It worked on the assumption that the lead singer's voice is always in the centre of the stereo picture and removed it by identifying the part of the signal which was equal in each channel. It was (is ?) most commonly used to produce a surround effect in domestic stereos, by pumping the treated signal to the rear speakers.

 

Is that of any use ?