Korg PA1X User Manual page 259

Diatonic and Chromatic
We've described scalic and chordal harmonies as diatonic, and
shift harmonies as chromatic; but what do those words mean?
Look at a piano keyboard. Between middle "C" and the next "C"
there are twelve keys – 7 white keys and 5 black keys. Each of
those keys are pitched one semitone apart for a total of, you
guessed it, 12 semitones. The chromatic scale uses all twelve
semitone notes opposed to the diatonic scales. Thus there is only
one chromatic scale, but 12 each of the major, minor, etc. dia-
tonic scales (C major, C# major, D major, etc). Most of us have
grown up hearing the traditional "doh ray me fah so la tee doh"
diatonic scale, so that harmonies based on the diatonic scale
sound correct.
What does this mean, harmony-wise? Diatonic scale harmonies
can only use notes within specified scale or chord, so a "third
above" harmony voice actually varies between three and four
semitones above the lead note where the chromatic harmony
would stay exactly four semitones (a major 3rd) above each note.
To recap: we have three different harmony modes that use chro-
matic or diatonic scales.
Shifting, which uses the chromatic, 12 semitone scale, changes
the input pitch by a fixed number of semitones:
Chordal, which uses the root, third, fifth and sometimes seventh
of the many diatonic scales, pitches the harmony voice to the
closest note contained within the chord:
Scalic, which uses one of many diatonic scales, pitches the har-
mony voice to the nearest note contained within the scale:
Theory aside, the best way to get great sound is to experiment
with all of Voice Processor' possible harmony modes. Not only
will you develop an intuitive sonic sense of what works best
where, but by investigating different permutations and combina-
tions you could discover some delightful sounds you might oth-
erwise have missed.
Global edit mode
Harmony and Tuning with the Voice Processor
Just Tuning
Why just tuning? Although probably no one has ever told you
this, your expensive grand piano and the last great keyboard syn-
thesizer you bought are both out of tune! Well, to be fair we can
say instead that they are all tuned using Equal temperament.
Harmony is the result of the interaction between differing audi-
ble frequencies in ratios that sound musical to the human ear. A
more exact ratio leads to a nicer sounding harmony.
Most instruments (like the piano) are absolute by nature. Each
note on the keyboard has a specific pitch. Equal temperament
tuning uses approximations for the tuning of each note, allowing
us to easily alter the key of our music without re-tuning our
instruments. Unfortunately, with this method of tuning we lose
the ability to create perfect ratios when playing multiple notes.
As a result, much of the harmony you've heard in music has not
been perfectly in tune!
The bottom line is that the approximations of equal tempera-
ment tuning are practical, but imperfect. Using the Voice Proces-
sor with Just tuning will definitely expand your musical
horizons!
Just tuning is practice of maintaining the relative (and perfect)
ratios between pitches, creating perfect harmonies.
Singers, especially when performing multi-part a cappella
music, base their tuning on how it harmonically sounds with
other singers. The natural tendency, and what sounds best, is to
sing with "just tuning" so that beating is minimized. One of the
goals in barbershop quartet singing is to strive for "just relative
intonation" so that a sub-frequency is audible. Achieving this
goal results in what barbershop fans often describe as the cov-
eted "ring and lock" sound. In barbershop music it is the lead
singer's responsibility to try to sing the melody as close to the
tuning of a piano (equal temperament) as possible. The other
singers must then tune their harmonies to the melody using "just
relative intonation". The Voice Processor is able to do this in both
the Just and Barbershop tuning modes.
When the Just or Barbershop Modes are selected in the Voice
Processor, the harmony tunings are based on the following rela-
tionships:
Minor 3rd 3 cycles for every 4 cycles of the input
Major 3rd 5 cycles for every 4 cycles of the input
5th 3 cycles for every 2 cycles of the input.
Barbershop differs from Just tuning in Chordal mode. Just tun-
ing will use the root of the chord for the tuning reference, while
Barbershop tuning uses the input notes as the tuning reference.
For this reason it is better to use Barbershop in an a-cappella sit-
uation and Just when playing with other instruments, because
Just tuning sounds more in-tune with the other instruments that
most likely have equal temperament tuning.
Our best advice is to experiment and use your ears!
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