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Topic: Midi Temperament Adjustment (Read 2749 times) previous topic - next topic

Midi Temperament Adjustment

I think I may have raised this one before, but I would be really interested to know if there is a gadget out there which would adjust the notes in a midi transmission so that the end result was in something other than equal temperament. I currently use a shareware programme (midrel32.zip) which I found somewhere on the net, but of course I have to have the PC switched on which is quite noisy (but not half as noisy as a Pentium 4 machine). By adjusting the midi settings in control panel I can send the midi information back into my keyboard if I want to, but then there's a latency delay.

Could a simple box of tricks be designed to do this, ie, to adjust all C's by a certain number of cents up or down, the same for all other notes by their own amount. The idea would be to have 5-pin DIN input and output sockets so the thing would go between two midi devices. Different temperaments selectable by a rotary switch would be a luxury!

Any offers of help or advice on searching for a solution would be appreciated.

Re: Midi Temperament Adjustment

Reply #1 –
My 0.05 euro:

Adjusting the pitch of the notes in a midi channel may be done thanks to the "Pitch bend". Too bad, it affects all the notes in the channel, thus a chord with 3 different notes should use 3 channels.

However, if your usage of the midi device (with equal temperament) is of 1 channel only, then your box could:
  • define different pitch bends for 12 differents channel
  • send each C to 1st channel
  • send each C# (resp. Db) to 2nd channel
  • send each D to 3rd channel
    ...
  • send each B to 12th channel
Note that channels #10 and #16 should be avoided since one of them is traditionally used for percussions (usually #10).

Re: Midi Temperament Adjustment

Reply #2 –
Sounds good, but my keyboard only sends everything out on one channel. But I suppose the magic box could first split the notes into channels as you suggest and then recombine them afterwards.

Some more headscratching required. Is this something I could learn to build with simple components (built a so-called water softener once with a pic chip in it)?

Re: Midi Temperament Adjustment

Reply #3 –
Hi Jeremy,

Assuming that you're comfortable with applying pics, your problem boils down to two aspects: the hardware and the software.

A good starting point for both is Jeff Glatt's excellent MIDI Technical Fanatic's Brainwashing Center.

I assume you've already scoured the web for an existing "magic box" as you describe? It would seem to be a handy gizmo, although many of the newer keyboards include tempering facility onboard...
 

Re: Midi Temperament Adjustment

Reply #4 –
In Reply #2, Jeremy wrote :
> Sounds good, but my keyboard only sends everything out on one channel.

This is a good start : there would be a problem if your keyboard already sent things out on more than one channel.

> But I suppose the magic box could first split the notes into channels as you suggest and then recombine them afterwards.

The magic box should first split the notes into channel, and it should not recombine them. Also, the receiving MIDI box should be able to receive notes on several channels, which I think is usually the case.