MIDI implementation & Yamaha XG

Ahoy !

Another note about my (mis)adventures with the Yamaha PSR-530
XG compatible keyboard.

BTW, you can microtune from the front panel, and set master tuning in
cents too. Very limited no. of parameters are accessible from there
though.

Last night I suddenly realised that each channel can be microtuned
differently!
Yup, ea. of the 16 channels can hold a different "scale tuning". I
checked.
So, though the method of shifting the pitch of one side of the keyboard
split works for a number of tunings, I don't have to do that, I can just
set up
a different tuning for each side.

Now:
Beware, beware, be very, very, ware of your synth's pitch bend and
RPN fine tune parameters. It would appear that manufacturers are pretty
nonchalant with their implementation of these parameters.
No using pretty spreadsheets to generate values.

Following my boo-boo mistaking the +/- 64 scale tuning for 64ths of a
semitone,
and then realising Yamaha had actually documented it correctly as
actual cents, I decided to check ALL pitch parameters using SysEx and
Hansruedi Baer's Digital Oscilloscope Version 2.1 . I recommend everyone
with
a Mac (PowerMac&68k) get it (& those without go look for one). It's
freeware !
An Oscilloscope and Frequency meter rolled into one. Very nice. Not a
toy, but
simple enough for the Xenharmonic/Allotonic neophytes among us,
like yours truly.

I figured out the SysEx messages for all the Pitch related parameters in
the PSR-530,
there are a total of 8. And most seem to work as advertised in the
manual.
The multipart detune parameter is (-12.8..+12.7 [Hz]), and being Hz, it
works
logarithmically, i.e., when set to the max +12.7, all keys don't go up
12.7Hz, only
the B key does. The C key goes up @ 6.7Hz.

Pitch bend, I checked with the range at 1-semitone and
found no clear pattern in the data values that caused each successive
pitch change.
Graham Breed mentioned he does this and
David Finnamore posted a note cautioning about it, you HAVE to check
the frequency of the bends against actual cent frequency equivalents.
The
pitch bend implementation in the PSR appears to be quite coarse.
The RPN channel Fine Tune parameter is very odd, completely ignoring
the LSB, and going from the equivalent of (-100 to +98 cents).
So, here again, it it means checking for the desired pitch.

And the SysEx (SYSTEM) Master Tune parameter (-102.4..+102.3Hz) doesn't
appear to yield any more accuracy than the MIDI Master Tune
(-100..+100cent)
parameter. I was trying to use it to get the pitch of the C key to 256Hz
which means
going down @ 37.63 Hz, but the best it gets to is @256.25Hz.

BTW, I adopted Joe Monzo's system of tuning the fundamental, and refer
to it as the
Monzo Fundamental, so if there isn't another name for it, and it's o.k.
with you,
Joseph..... We haven't heard a peep out of you lately, must be the road
trip,
you around or too busy burning asphalt ?

Cheers,
Drew

On Thu, 3 Sep 1998, it was written:
>I have nearly completed my custom MIDI keyboard ( final year electronic project
>at university ). The keyboard is not a performance device, as it has just over
>an octave and has buttons rather than keys, but is intended to allow the
>exploration of 19 TET on a more intuitive interface than a confusing standard
>synth keyboard.

This isn't what you asked for, but you might be interested in the
following message (forwarded from HPSCHD-L, which is currently in an
uproar over the idea of applying now for a patent on something that
people have been doing for hundreds of years). There may be a job
waiting for you at Yamaha, unless the harpsichord contingent sues their
asses off. 8-)>

*** BEGIN QUOTED-MESSAGE ***
>From pickett@blumlein.music.indiana.edu Thu Sep 3 15:08:29 1998
Date: Sun, 30 Aug 1998 14:49:39 -0500
From: d a pickett
Reply-To: Harpsichords and Related Topics
To: HPSCHD-L@CNSIBM.ALBANY.EDU
Subject: New (?) from Yamaha

The June 1998 issue of the Journal of the Audio Engineering Scoiety
describes a patent (5,516,981, assigned to Yamaha):

"Musical Instrument Tuned in Nineteen Note Temperament Scale

This patent assumes that some of the musical chords using the 12-tone
equally tempered scale are not sufficiently consonant from the
standpoint of minimizing beats. Equally tempered scales are examined
that have a larger number (19 or 31) of notes. It is concluded that 19
notes per octave provides musical intervals having a smaller number of
beats while still being manageable for the playing musician. Examples
are given for keyboard, brass, woodwind, and percussion instruments."

Ther is an illustration of a keyboard layout similar to that of a
chromatic harpsichord.

Should we consider as a list bringing a class action suit? :-)

david
*** END QUOTED-MESSAGE ***

--pH http://library.wustl.edu/~manynote
O
/\ "Churchill? Can he run a hundred balls?"
-\-\-- o
NOTE: dehyphenate node to remove spamblock. <*>

> I have nearly completed my custom MIDI keyboard ( final year electronic project
> at university ).

Neat! Out of curiosity, which university?


> I want to know if there is any preference as to what MIDI note number
> coresponds to each key.

I'm not personally aware of any such standard. Although if you want to
maintain A=440Hz as an absolute-pitch standard, then perhaps it might make sense
to make that be the common note.