Can you subtract from the frequencies of a track... another track's frequencies?

[rasputin1963]

Is there a way to do this? I want to subtract from Track A... all the frequencies present in Track B. Then later blend the two, such that they fit together, hand-in-glove, to form a "third" sonority?

 

Wild, I know, and possibly unorthodox, but I am in an experimental mood.

 

Is there a proggie that will allow you to view the spectrogram of two tracks simultaneously... but maybe one in a different color than the other, so you can do some judicious "sonic surgery" on the two tracks?

 

Thanks, ras

[BobF_]

Inverting the phase of track B should get you close for step 1 ...

[Anderton]

+1 on the phase reverse concept.

[philboking]

Inverting the phase of track B should get you close for step 1 ...

 

This will work under certain conditions:

1) The track containing stuff to subtract must be a sample-exact duplicate of the sound in the already mixed track. For example, if the mix was compressed or EQ'd or had other FX (such as delay/phasing/flanging/chorus,etc.), you're probably out of luck.

 

2) The two tracks must be perfectly (or nearly perfectly) sample-aligned.

 

3) You must level-match the inverted 'stuff to subtract' track with the level of that instrument or sound in the mixed track. If you got the first two, this one can probably be done by ear to a satisfactory degree.

 

Sorry if this is bad news; I'll always feel that it should have worked out for you...

[WRGKMC]

I'd have to ask are these two tracks identical or not.

 

Phase reversal works on identical tracks but two different parts with two different instruments, settings, mic positions etc will vary allot using phasing. If the mics are the same and unmoved in position you may only get the notes that are similar canceling.

 

If you want to view the two, simply download Voxengo Span. http://www.voxengo.com/product/span/

 

Its a dual Trace Frequency Analyzer that can view two channels at once. Just stick it in your master buss, pan the tracks hard left and right and solo the tracks and you'll see each track in different colors when stereo viewing is selected.

 

 

You can leave the frequency analyzer running while you bring up the EQ's for each track and do whatever comb filtering you want between them.

 

Not sure what you're trying to obtain with this third ghost track consisting of the two. From my thinking that's the stuff you normally want to minimize to prevent the two tracks from masking each other. But as you said, you're experimenting so go for it.

 

Span is a great free plugin. I've used in in several critical situations. I did one session recording a band and recorded guitarist's amp with a mic and had extra tracks so I recorded his guitar through a direct box at the same time just for the hell of it. They did one song and he had some heavy duty effects running and his speakers farted out during his solo.

 

I used the DI track and the mic track and ran them through Span and used a bunch of plugins to build up the DI track to sound the same as the mic track. It took awhile. I had to compress, EQ, Use an amp emulator, EQ and compress it again but with the help of the analyzer I was able to match both the Gain and EQ curve of the original track. I simply faded the track over the bad part and there was no way you could hear a difference.

 

I couldn't have done it that transparently without the aid of a frequency analyzer.

[Phil O'Keefe]

The problem is that the frequency content of a track varies from moment to moment. Play a different note, and everything changes. The "hole" you want to create is constantly changing.

 

What you're asking is something mix engineers do fairly often in the general sense - pull frequencies out in order to make room for something else - but it's not "all the frequencies" - just pulling out some stuff to make room for other things. For example, you might pull out the stuff below 100Hz or so on the electric guitars to make more room for the bass and the kick drum in the mix, or dip the 1-4kHz region of a guitar or keyboard part to make more room for the articulation of the lead vocals, etc.

[dboomer]

I used to use a free Windows program which compared two tracks and spit out the differences. It had the ability to automatically exactly line up the two tracks under consideration.

 

I mainly used to to compare data compression schemes and codecs. It was called something like A/B comparator. Look around and see it you can find it.

[Phil O'Keefe]

Don, was that a sum and difference type plugin?

[dboomer]

Just the difference. A great way to tell just what quality you lost (or not) from different codecs or sampling frequencies. It wasn't a plugin but rather a stand alone program. You just attached your A and B files.

[MikeRivers]

Is there a proggie that will allow you to view the spectrogram of two tracks simultaneously... but maybe one in a different color than the other, so you can do some judicious "sonic surgery" on the two tracks?

 

Are you talking about two different tracks, like a piano track and a trumpet track? Or the left and right tracks of a stereo recording? I think you're on the right track with a spectrogram but time alignmment is a major factor in whether "nulling" will get you anything useful

 

 

[philboking]

 

This will work under certain conditions:

1) The track containing stuff to subtract must be a sample-exact duplicate of the sound in the already mixed track. For example, if the mix was compressed or EQ'd or had other FX (such as delay/phasing/flanging/chorus,etc.), you're probably out of luck.

 

2) The two tracks must be perfectly (or nearly perfectly) sample-aligned.

 

3) You must level-match the inverted 'stuff to subtract' track with the level of that instrument or sound in the mixed track. If you got the first two, this one can probably be done by ear to a satisfactory degree.

 

Sorry if this is bad news; I'll always feel that it should have worked out for you...

 

I just thought of something... this would be a good way to get reverb-tails-only from an instrument track rendered with reverb, by subtracting out the dry instrument. I'll have to try this & see if it gives me anything cool from it. It might be sort of cool on drums or something.

[BobF_]

Another idea is to get creative with mid-side ...

[Phil O'Keefe]

 

I just thought of something... this would be a good way to get reverb-tails-only from an instrument track rendered with reverb, by subtracting out the dry instrument. I'll have to try this & see if it gives me anything cool from it. It might be sort of cool on drums or something.

 

If you still have the original (dry) track, why not just use a pre-fader send to feed the reverb? That will give you just the reverb if you want by turning up the aux send and keeping the source channel fader all the way down, giving you no dry source.

[dboomer]

Too easy! 😄

[WRGKMC]

The thing to keep in mind, the frequency content, contains the musical notes (or the notes create the frequency content). Outside of that area there is nothing but noise. You can attempt to boost weak frequencies but you risk increasing the noise floor.

 

I still haven't got a clue what the OP is really trying to achieve. If you break it down to the simplest form and have two single sustained notes, and those notes are either in pitch or at different intervals, what do you have? Harmony Unity or Dissonance.

 

You can use effects on these notes, but I don't see many creating a third voice.

 

You can use one of the notes to trigger a harmonizer to create a third voice, but its linked to the one note at an interval.

 

There are other Ducking and phasing effects but these essentially remove frequency content or attenuate and have no effect on the notes themselves.

 

There's only one option for creating this third voice that's dependent on the other notes. I learned about it from my Sister who sang in many Choruses and Musicals. It involves reverberation in actual halls using the human voice. You can get two or more voices producing specific pitches which excite the hall and generate an actual third voice.

 

A good example of this can be heard on the sound track or 2001 Space Odyssey. The chorus of voices sound like they are singing odd scales but what they are doing is building up room, much like wind pushing water back up a river until the reverberation oscillates. In back of the voices you hear these higher frequency tones appear which sound like strings on an acoustic violin fading in and out like a self sustaining guitar string in front of a loud amp. These are actually the overtones of the voices making the air the hall regenerate and produce a third or ghost voice.

 

Papa John from the Mammas and the Papas called it Elmer. When their vocals were really tight you'd hear this ghostly voice appear way up near the ceiling. Buddhist Monks would use their chants in cavernous halls or caves to produce this same kind of acoustical compression to force additional voices to appear.

 

Using the right kind of reverb setting on the tracks may be able to generate some of this. Synthetic reverb isn't nearly as good as the real thing but it might be worth investigating. The notes do have to be longer however. Random transients may disturb the regeneration whereas intentional transients and wavers can be used to tickle and coax the third (4th, 5th, 6th) voice to appear.