Apple Logic Pro 7 - Manual (Page 632)

632 Chapter 21 Song Settings and Preferences
The Comma
The difference between a perfectly tuned octave and the octave resulting from a tuned
circle of fifths is known as the “comma”.
Over the centuries, numerous approaches have been taken to solve this mystery,
resulting in a range of scales, and finally arriving at the concept of “equal temperament”.
Other temperaments that have been devised throughout history maximize or
emphasize different aspects of harmonic quality. Each compromises in some way or
another. Some maximize pure thirds (Mean Tone) while others emphasize pure fifths, at
the expense of the thirds (Kirnberger III, for example).
Every temperament has its own “character”, and a given piece of music may sound fine
in one key, but awful in another. Transposing a piece to a new key can completely
change its character.
Careful attention must be paid to the selection of temperaments for authentic
performances of historic keyboard music. The wrong choice could result in an
unsatisfactory and historically inaccurate musical experience.
About Equal Temperament
Equal temperament takes the tuning ‘error’ (the comma), and spreads it equally
between each step of a chromatic scale. The result is actually a scale of equally mis-
tuned intervals, with no interval grossly out of tune, but none in perfect tune. Equal
temperament has become the de-facto standard for two main reasons:
• Convenience—Retuning an instrument to a specific temperament that is better
suited to a particular piece of music is a hassle.
Many instruments are not capable of being alternately tuned (fretted string
instruments, for example).
• Portability—All Western musical pieces can be performed (adequately) on an
instrument tuned to equal temperament. Obviously, some of the nuances may be
missing for pieces that were originally performed in another temperament. On the
flipside, pieces that depend on equal temperament may sound terrible by the
placement of various mis-tuned intervals.
What is Hermode Tuning?
Hermode Tuning controls the tuning of electronic keyboard instruments automatically
during a musical performance.
In order to create clear frequencies for all conceivable fifth and third intervals in all
possible chord and interval progressions, a keyboard instrument would require a
significantly higher number of keys per octave instead of the usual 12.