Why CM7? Why not just C?

[Fred Smith]

All tutorials say styles have to be constructed in the key of CM7. Why not just key of C? What's the difference? Why do they specify it has to be CM7?

Thanks,
Fred

[mikf]

Fred, it's not actually the key of CM7. It's actually root C, which really is the same as key, and the chord type is M7. I believe the reason why it's important is because the NTT and NTR are affected by the chord type you select on original style part recording. Of course you don't have to, you can select another root like D, and the record that part in key of D, and it will accurately transpose when you play any chord live, just as it would if you use C root. You can even mix and match each style part recording with different roots, although hard to see why you would.
You can also select another chord type - like maj or even min. But when you do that will subtly change the NTT.  So it might not accurately transpose exactly as you expect when you play other chords.
There are many choices you can make in the style parameters which change how the NTT and NTR work, to produce different results. So for example you can select "GUITAR" and the NTT will then select note intervals like a natural guitar chord position.
It's all very complicated, but amazingly powerful for those that take the time to understand it all, which I hasten to add I have not,
However, taking a look at this video might get you the idea. It might also make you decide to stay well away from style creation!!!
Mike
https://www.youtube.com/watch?v=3439W4rIn-g

[Joe H]

Fred,

I think because there is a B note included in the CM7 scale/chord.  The B is needed for 7th chords.

I think is correct anyway... I could be wrong about that.

 

BTW... sometimes Yamaha uses the Am scale... it has the same notes but the root is A instead of C.

Joe H

[mikf]

I don't think it affects transposed chords in play back. If you play a maj 7th you should get a maj 7th regardless of the setting. It's because when you record style phrases (in bass or phrase channels) you can only record the 7th note (B) if you use the M7 setting. If you use other settings like maj rather than M7, the notes you can record change and do not include the B. So that could be quite restrictive when recording style phrases.
It's still a bit restrictive because even in the M7 setting you cannot record for example a Bb in a phrase. But I think there are other settings you can change in NTR and NTT like "melodic" that allow a wider range of phrase notes. It's a bit of a minefield. Gets even worse when you try to record style intros.
Mike

[mikf]

YammyFan
The AI setting has some complex algorithms at work to influence accompaniment, and as well as what you actually play, can use melody notes and I think common chord progressions among other things. I am not sure that anyone outside a  Yamaha few really knows all that goes on in AI algorithms, but you can see what it plays by looking at the chords on the screen when you play.  But it still largely plays what you play, so it will probably not 'play the really difficult chords for you'.
I use it to drive accompaniment from both hands when playing full keyboard mode, ie not simple lh chords rh melody, and it seems to work well for this, properly interpreting most of the time the altered and extended chords I am playing.
BTW - this is a very different topic from the original post, so I think you should delete and re-post under a new thread with different title.
Mike

[DaffyDuck1]

The simple answer is it doesn't know how to convert Maj to M7, but it knows how to convert M7 to Maj. So if you want to have M7 chords in your style you have to record it in M7 and show it how you want your M7 chords to sound, and then it can figure out how to turn them into Maj automatically. If you don't care about M7 chords then you can record it in either, your M7 chords would sound the same as Maj in this case. So by recording everything in M7 you are giving it more information which it can use to better convert your chords to other types.

You might be surprised that it cannot do a simple Maj to M7 conversion by just adding B note there, but the problem is the style player cannot add new notes to your recorded chords or melodies, it can only transpose recorded notes (can also mute them in the guitar mode). So if you recorder a 3 note chord it can be transposed into 1 or 2 or 3 note chords, never 4. Let's say you recorded C-E-G, what would be a good 3 note M7 conversion here, C-E-B? B-C-E? C-B? There is no solid universal conversion rule that would always work so it's not attempting it.

On the other hand converting from M7 to Maj is easy and works much better. The rule it uses is C-E-G-B gets converted to C-E-G-C. It's still not ideal as you cannot have your major triads and 4-note M7 chords at the same time in either case, so you have to decide for yourself what do you prefer - record it as C-E-G under CMaj (or CM7) and have no unique M7 sound, or record it as C-E-G-B under CM7 and have you Maj chords turn into C-E-G-C. The only proper solution to have 3-note Maj and 4-note M7 at the same time is using CASM editor software that lets you record 3 note and 4 note chords at the same time into different channels and then play one or the other based on whether it's Maj or M7, and that's what factory styles often use.

[Joe H]

The only proper solution to have 3-note Maj and 4-note M7 at the same time is using CASM editor software that lets you record 3 note and 4 note chords at the same time into different channels and then play one or the other based on whether it's Maj or M7, and that's what factory styles often use.

I think what you are saying is you can specify in the CASM settings to have an alternate channel (channels one to eight) play when you specify a 7th or minor chord. For a minor chord or arpeggio you must play a Cm chord/scale on an alternate channel. This will create variations when playing a style using different chord types.

Joe H