Re: Real Tracks #WindowsUsers #BiaBPrevious

David H. Bailey

Hi DF,

I would love to hear you build an accompaniment to "Ain't Misbehavin'" using your method. The most common key I see that song in is Eb. The style I would like to hear is a jazz trio (piano, bass, drums).

So, using a $700 program (the polyphonic version) or even the $99 version (the monophonic version), you will be able to build me an accompaniment (3 choruses, variation in the middle chorus, 4 bar intro, 2 bar ending)?

Cool -- it's the "laborious" bit that would prevent me from even trying.

I just listened to a bass track and think that there is much more at play than simply a pitch-shifting algorithm. After all, they have to mix the various wma files so that we don't hear one single bass lick being played over and over again.

If you can do it, great.

I'm not sure why anybody would want to, though, given the very laborious nature of what you're describing.

Far easier to have BIAB create the song form, start to finish, with intro, ending and various choruses with A and B styles mixed, and then work from there.

But as you say, it's possible . . .

Thanks for outlining how it could be done!

On 12/3/2020 1:18 PM, D F Tweedie via wrote:
David ...
I'll take you up on your challenge!
Here's how to do it ... assuming the RealTrack elements are unencrypted either as WMA or Wav files.
Laborious, but technically easy.
You need a high-end pitch editor such as Celemony's Melodyne. That program can identify the pitch/ key of an audio sample with very high accuracy and has absolute accuracy on a note by note basis.
It can also correct to perfect pitch at 440 hz concert or to whatever other standard such as 432 hz if you prefer.
Now take those three or four identical passages from a RealTrack and identify their actual key (if it is not somehow already tagged in the file name.) For purposes of explanation lets say that the formula is C (or C minor, etc.), D#, F#, and A using 4 of the 12 possible keys a passage could be recorded in.
So if the opening bars in your song were in those keys, not a problem. Just pick the congruent one. But it the key was B, just pick the closest one, in this example C and put it in Melodyne and shift it down to B.
This or course would be laborious to have to stitch a song together section by section. But conceptually it would be easy to do and provide results equal to what BIAB outputs for RealTracks.
As a matter of fact, I'd bet the farm that this is exactly how real tracks work internally. If the sample isn't already in the correct key for the bars of the song, it has a pitch shifting algorithm that takes into account the requested key and selects the sample closest to shift from up or down.

David H. Bailey

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