RE: Quarter-tone MIDI

[Heikki Johannes Junes]

> >It appears to me that quarter-tone notes are not converted to the right
> >frequency in the midi format of the file. Is there a patch for this, if
> >not which source file needs to be modified in order to fix the
> >frequencies?
> >Thank you,
> >Morteza
>
>       I can't tell you which file needs to be modified but just in case
>       you are not aware of how to do it you need to ensure that
>       at least three MIDI messages are used.

File `lily/midi-item.cc' should be changed sligtly. There is now a
function that calculates the missing cents.

>       The first, to be on the safe side, is a Registered Parameter number
>       message which sets the pitch wheel sensitivity. Although the MIDI
>       standard suggests that all MIDI devices default to 2 semitones
>       up and down from the central position it would be a good idea to
>       ensure that in a file using quarter tones that this is set.
>
>       Controller 101 sets the coarse value, semitones, and controller
>       100 the fine in hundreds of a semitone. Next for each quarter tone
>       desired you need to prefix it with a pitch wheel message to
>       shift it's pitch in the desired direction and then send the note
>       on event and then reset the pitch wheel back to the central position
>       unless the next note on the channel is modified in pitch in which
>       case you need to move the pitch wheel to the desired position.

Does this have an effect on all the channels, one channel or one
instrument?

What are the exact midi command bytes if one wants to change c' -note to
cih' -note (i.e. add 50 cents).

>       For the gory details see:
>
>       http://www.borg.com/~jglatt/tech/midispec.htm
>
>       Hope this helps.
>
>       Nigel.

Looked like a good site for midi specs.

  Heikki Junes