I need a schematic for an OOPS circuit. I am looking to suppress vocals on a stereo recording.

 

Can you be a little more specific? The answer to the question, as you asked it, is to simply erase the recording.

 

" I am looking to suppress vocals on a stereo recording" is what I specified.
Erasing the recording is hardly the answer.
What I am looking for is an OOPS or inversion circuit diagram which will exploit the usual musical arrangement that has vocals on both channels.
So inverting one and then combining theboth will yield what is uncommon to either channel. It's like a karaoke machine, I suppose.

 

" I am looking to suppress vocals on a stereo recording" is what I specified.
Erasing the recording is hardly the answer.
What I am looking for is an OOPS or inversion circuit diagram which will exploit the usual musical arrangement that has vocals on both channels.
So inverting one and then combining theboth will yield what is uncommon to either channel. It's like a karaoke machine, I suppose.

Today, a DSP app will be a better solution for recorded files than the old analog inversion circuits.

 

That will also, of course, erase any music common to both channels such as the bass.
You may end up with a very tinny sounding recording.

 

Won't Audacity do it for you?

 

That will also, of course, erase any music common to both channels such as the bass.
You may end up with a very tinny sounding recording.

Yes, but it will most likely remove the vocals . . .

I actually want to build something for my grand-nephew. He's just gotten into music and a device as described would allow him to easily pick up melodies.
While he could lose the bass the vocals will most likely be attenuated by the device. and that's what i'm after.

 

Won't Audacity do it for you?

Thank you . . . and a software option will be considered.

 

A unity gain op-amp can provide a phase inversion over the audio frequency range. To keep things symetrical use a quad opamp with a non-inverting unity gain on the other channel. Then feed both into a summing junction of a third opamp.
It can also be done with a single op-amp, feeding one signal into the inverting input and the other into the non-inverting input, but balancing the gains will take a bit more effort.

 

A unity gain op-amp can provide a phase inversion over the audio frequency range. To keep things symetrical use a quad opamp with a non-inverting unity gain on the other channel. Then feed both into a summing junction of a third opamp.
It can also be done with a single op-amp, feeding one signal into the inverting input and the other into the non-inverting input, but balancing the gains will take a bit more effort.

Option 2, I think. Thank you.

 

I am still trying to understand how you plan on removing the vocals without removing the music. Your explanation does not make sense to me.

 

IN many stereo recordings the vocal track is identical on both channels, and likewise much of the Bass.
There is enough out-of-phase sound to leave an adequate amount to guide another to be able to duplicate the original. So the result is seldom an all-or-nothing situation.

 

IN many stereo recordings the vocal track is identical on both channels, and likewise much of the Bass.
There is enough out-of-phase sound to leave an adequate amount to guide another to be able to duplicate the original. So the result is seldom an all-or-nothing situation.

Well good luck to him. I don't think he will finish up with enough signal to be useful.

 

Well good luck to him. I don't think he will finish up with enough signal to be useful.

Given the number of vocal track removers that I have seen advertised, it seems that the theory of operation is sound. Different recordings will undoubtedly vary.

 

I have used such a circuit that I bought as s kit. The results were unimpressive, as others have suggested. The vocals were still audible, though attenuated, on most recordings and the bass was severely reduced.

 

" I am looking to suppress vocals on a stereo recording" is what I specified.
Erasing the recording is hardly the answer.
What I am looking for is an OOPS or inversion circuit diagram which will exploit the usual musical arrangement that has vocals on both channels.
So inverting one and then combining theboth will yield what is uncommon to either channel. It's like a karaoke machine, I suppose.

Vocals suppression will require that the phase inversion be applied only over the vocals frequency range - about 500 to 5 KHz. You better experiment and see the effect.

 

That will also, of course, erase any music common to both channels such as the bass.
You may end up with a very tinny sounding recording.

yes, that is possible.

 

A unity gain op-amp can provide a phase inversion over the audio frequency range. To keep things symetrical use a quad opamp with a non-inverting unity gain on the other channel. Then feed both into a summing junction of a third opamp.
It can also be done with a single op-amp, feeding one signal into the inverting input and the other into the non-inverting input, but balancing the gains will take a bit more effort.

that's very much what I expect to put together.
I believe a combo of TL084 and TL082 may do the trick.

 

that's very much what I expect to put together.
I believe a combo of TL084 and TL082 may do the trick.

A simple inversion circuit won't be very effective. There are DSP techniques specifically designed for signal separation that are being used in modern (and older analog systems) digital applications.
https://en.wikipedia.org/wiki/Signal_separation

https://forum.allaboutcircuits.com/threads/theory-of-everything.168244/post-1491830

 

I think the degree of suppression is going to depend on how the vocalist was miked. If the vocalist was using a stereo mike, or was not stage-centre during recording, there is likely to be a considerable left-right imbalance in the vocals recorded.