Hello folks,

I'm new in town.
Finally got on here after MUCH bugging of Nigel

I have a pet piano practice program that's kind of my life's work. And I'm trying to add style playing to it's list of features (as my Yamaha CP-33 won't do it in hardware)

I have a pretty good understanding of
- yamaha style file format (thanks to JorgenS,PeterW)
- chord qualities (and yamaha's list of defined ones)
- midi software in general (see my pet in the sig)

What I'm not understanding is how the notes of the style are transposed into the notes of the chord you PLAY.

I understand that the style file is keysig=C based and you transpose from C to the root of the PLAYED chord.
And I get that the style chord channel is based on a particular chord quality - usually CMaj7 so you need to scoot around the 1,3,5,7 chordals.

But I don't understand what to do when:
1) the style note isn't on the 1,3,5 or 7 of the style chord quality.

2) the played chord type doesn't INCLUDE a chordal of the style note. For example, you have a 4 note style with CMaj7 based C,E,G,B. And you PLAY a Cmaj. The B gets totally scooted to a new chordal as the played chord has no 7th. I can see how you want to play all style notes on SOME note to keep the rhythm, etc. But I don't understand how the new note octave,step is picked.

If anybody can help me with this, I'd greatly appreciate it !!

Well, I'm looking for the logic of how a program like vArranger works.

Not looking for one to just use. Looking to code my own.

So ideally somebody who has composed a style can help me.
By telling me how they write arrangements in a chord channel so that they know it will sound good when transposed by the arranger.

My big problem I need to understand is when the style has a 5 notes chord and the PLAYED chord is major (only 3 notes) - how does the arranger software pick the new octave/halfstep for the extra 2 notes.

Welcome to the forum Stephen Sorry about your less than salubrious first reply above....

The number of notes in the chord is not really relevant, as the algorithms are looking at individual notes played rather than a specific preset chord structure.

These are then analysed by the NTT (or Note Transposition Tables) which reads each note you are playing - even if it is 8 notes! - and transposes each one according to the "rules" set. IE Close harmony, parallel, moveable root, fixed root etc.

So it moves the notes you are playing from the style programmed C based patterns to the chord you ARE playing. If you check out the Recognised Chord charts from the manuals of any of the arranger manufacturers you will see how many different chord structures are recognised.

Dennis

Hiya Dennis,

There are some chord trigger modes that mix your triggering with the output, but in general i THINK that your left hand ONLY picks a chord root and quality. The chord is first transposed from C to that root, but from what I've seen in some experiments, ALL of the style notes ALWAYS go out.

If there's an exact match between the chordal (1,3,5,7) in the style's channel's chord quality with the chord quality you PLAY, then the style notes go out with just the root transpose plus 3,5,7 adjustments due to chord type.

BUT if the style channel was recorded with CMaj7 C,E,G,B and you play a Cmajor, then since the 7 is extra, it gets mapped to a 1. That B gets remapped to the next C up.

(Then voice leading logic is thrown in on top).

Let's take a look at a relatively tricky example:
style channel is based on Cmin7(11) and has these notes:
3Eb 3F 3Bb(3,4,7)

now you play Cmaj, Cmin, Cadd9.

Major has the 3, but it's adjusted to a M3 instead of existing m3 so 3Eb=>3e
No 4 or 7 in Cmaj, so the 3f=>3g(4=>5) and the 3Bb=>4c(7=>1)

When Cminor is played, the same thing happens, but the 3 is left minor.

Now you play a Cadd9.
3Eb adjusts to major again.
3F is moved to a 5 again (3F=>3G)

=BUT= the 3Bb is moved to a 4D. (So 7=>2)
How did it decide to skip over the 4c which is IN the played chord???

Maybe that has to do with the voice leading logic?
Hmmmmmm............

I think what I'm gonna do is build an arranger that just redistributes the style notes onto new chordals from "as recorded in style" quality to "as wanted by PLAYED chord" quality in as plain a manner as possible - just pick the next dang chordal up valid in played chord. And see how it sounds. It won't be an identical arrangement to yamaha's. But it'll still sound good per chord quality.

If a style composer happens by later and can fill me in, I'll change my algorithm.

In addition to the weird yamaha "pick next chordal" thing, there are also cases where ONE (or some) of a style's note(s) are duplicated. Not just shifting the chordal, but making a whole new one.

Here's an example:
style channel was plain CMaj7 chord quality with 3g,4b,4e notes

when major chord is played, out come 3g,4c,4e as you'ld expect. As 7 is often hopped to 1

BUT when C79 is played, out comes 3Bb,4c,4e,4d

Where the heck did that extra note come from??? The style only had 3 notes...

Hi Stephen,

I could only suggest that you try to discuss these and other stuff with people like Dan, that already did work in this area.

For regular users, the technicalities of chord recognition and whatever else might be an unknown or less familiar territory.

Do you need an GUI for the program? I could help you with that...

Who is Dan?

I'm planning on making this part of my PianoCheetah program. So you do some GUI sorts of things? Have any apps to show?

Thanks for your pointers,

...Steve

Send Rikki (rikkisbears) a message - she is an acknowledged whizz on style creation...

will do