[linux-audio-user] Midi tuning control?

[tim hall]

On Tuesday 10 January 2006 19:30, M P Smoak was like:
> Setup: older roland kbcontroller mkb-200 and SBlive w/soundfont;
> works great for weekly practice group session, my solo practice,
> ..., and I'm enjoying it and linux audio.
>
> But sometimes I need a pitch (tuning) slider; some way to easily
> "tune" the keyboard to an out-of-tune recording, piano, etc.
> (Years ago, I used win31/sb&roland-daughter-card and there was an
> effects program that could tune. But it required use of computer
> kb and mouse so it wasn't what I'd call easy.)  Right now when
> this need happens, I just quit playing kb and pick up my sax :>)
>
> I've never created a useful midi recording;  I use it just for
> a keyboard to play. (Recently bought the book for Rosegarden and
> one these days, I hope ..)  So I don't know much about midi ways
> of controlling stuff.  The mkb-200 has 2 sliders for volume
> (lower and upper kb split), modulation (depth & risetime)
> sliders, pitch-bend wheel which is also modulation on, and
> buttons for stuff like channel, voice, after-touch, ...  I have
> now idea how any of these might be used, or if some other midi
> device that I could buy, might give me a tuning slider.
>
> Is midi pitch tuning a part of any linux program like rosegarden,
> or a synth program or ???  If so, do any not require computer kb
> and mouse?
>
> Is there a command line way to do it?
>
> I've done a bit of googling on this without joy so far.  Am I
> missing something obvious, or am I the only one that runs into
> the need to tune to someones out-of-tune instrument?

No, you're not the only one.

If you really want to do pitch adjustments to MIDI, you need to look at 
something like scala http://www.xs4all.nl/~huygensf/scala/ or at least figure 
out how to make microtonal adjustments to the pitch-bend controller. This is 
not really the correct way to go about it as MIDI is nothing more than a 
digital piano-roll, it only cares about the notes of the scale not the 
frequencies. That said, scala is a fascinating package if you're interested 
in microtonality.

The only synth that does this properly is ZynAddSubFX 
http://zynaddsubfx.sourceforge.net/ Zyn features global pitch adjustment as 
well as the possibility to reproduce any temperament. Works well with  the 
temperament definitions from scala. 

Most external keyboards should be tuneable, my D10 has a 'master tune' 
setting, I would have thought your mkb-200 does somewhere too. 

Actually all softsynths _should_ be tuneable, but too many developers seem to 
assume that A=440Hz is the standard pitch and don't provide an easy way to 
change this. I'm beginning to regard pitch adjustment as a required feature. 
I'm thinking a couple of clearly worded feature requests might not go amiss 
here.

There is also a LADSPA plugin - AM pitchshifter (amPitchshift, 1433), Pitch 
Scaler (pitchScale, 1193) or Higher Quality Pitch Scaler (pitchScaleHQ, 1194) 
are probably the ones you want. This way you could tune the recording to your 
keyboard.

AFAIK getting a slider to do this would involve figuring out some way to hook 
up a MIDI controller so pitch bend is controlled by a slider rather than a 
sprung lever. Possibly not rocket science. I have never tried it.
-- 
cheers,

tim hall
http://glastonburymusic.org.uk/tim