E-Mu XK6Xtreme Keys Owner's Manual page 179

   
XK-6 implements the
MIDI Tuning Dump protocol
which allows you to create
tuning tables on your personal
computer and download them
via MIDI. There are several
computer applications available
on the internet which let you
create and download tuning
tables via MIDI.
The Just C Tuning Tables
Well Tempered and Just were standard keyboard tunings up until the 20th-
century when the current "equal tempered" scale became prevalent. In an
equal tempered scale, the octave is equally divided into 12 parts. In Just or
Well Tempered scales, the 12 notes are separately tuned to produce pure
chords. However, in Just tunings you are limited to playing certain chords
and if you play the wrong chord it may sound very BAD!
XK-6 allows you to modulate between keys by providing you 12 user tuning
tables. Tuning tables can be changed as you play using a program change
(create several presets with the same sound and different tuning tables), by
MIDI SysEx command (using a programmable MIDI footswitch or other
device), or using a continuous controller (link 2 presets and crossfade
between them using a controller).
The Just C2, Just C min, Just C3 Tuning Tables
These new tuning tables take the concept of just intonation a step beyond
previous E-MU products. Fully explaining the mysteries of just intonation is
beyond the scope of this manual, but the subject is covered exhaustively in
Hermann Helmholtz's On the Sensations of Tone, available at most libraries
and bookstores.
The new tables are called Just C2, Just C3, and Just C Minor. Try playing in
the key of C/Cm using each table. You'll quickly discover both the wonders
and the frustrations of just intonation! In Just C, for example, you'll find
that the chords C, Em, F, G, and Am sound beautiful. If you hold one of
these chords, you'll hear no "beating". After playing for a few minutes,
switch back to Equal Temperament for a rude awakening!
At this point you might wonder why anyone would use Equal Temper-
ament to begin with. For the answer to that question, play a D, Dmi, or Bb
chord!.The intervallic ratios that make the C & G chords sound so pure
make the D chord sound horribly out of tune. That's why we had to include
Just C3. In this tuning, D, Dmi and Bb sound in tune, but the G chord will
sound wrong.
Each of the 4 tables allows you to play a different group of common chords
in just intonation. Sadly, there is no single 12 note tuning that will allow all
of the common chords to be in tune, and of course that's why they
invented the equal temperament tuning system that we use today.
Just C
C, E, F, G, A, Cm, C#m, Em, F#m, Gm, Am
Play these chords:
Just C2
C, E, F, G, A, B, C#m, D#m, Em, G#m, Am, Bm
Play these chords:
Just C2 minor
C, D
Play these chords:
Just C3
C, D, F, B
Play these chords:
b b b
, D, E , G, A , Cm, Em, Fm, Gm
b
, C#m, Dm, Em, F#m, G#m, Am
Preset Edit Menu
Keyboard Tuning
XK-6 Owners Manual 169