[comp.music] Tempered scales What is perfect pitch?

alves@aludra.usc.edu (William Alves) (12/02/89)

In article <128650@sun.Eng.Sun.COM> briang@sun.UUCP (Brian Gordon) writes:
>
>We moderns (over the last few hundred years) have become used to the
>deliberate mistunings of important intervals in common keys as "right", but
>really notice the difference in intervals in less common keys -- the ratio of
>a sixth in the key of C is really quite different that the ratio for that
>interval in C# on a piano.  A common perception is that the sharp keys are
>"brighter" and the flat keys are "mellower".
>
You are probably thinking of various meantone temperaments or "good" tem-
peraments of the eighteenth century and earlier. In these temperament systems
the commonly used keys were indeed better than the less commonly used ones.
That is not true in equal temperament. If your instruments are in tune, there
should be no intervallic difference between sharp and flat keys.

I, too, have come across musicians without perfect pitch who claim to hear a
difference of "mood" depending on a piece's key in equal temperament. There
could be several explanations. First of all, all acoustic instruments, es-
pecially the voice, change timbre on different pitches. Thus transposing some-
thing up or down can often change the "sound" of it, but not the intervals.
Second, though these people may not have perfect pitch, a transposition of a
minor third or so will be noticed by a lot of them simply because it's high-
er, even though they can't tell you exactly how much. Finally, musical con-
text could even have something to do with it. I once did an impromptu test
on a friend, who unconsciously associated strongly pentatonic melodies with
the black keys.

Of course, if the instrument is not an absolutely tuned one (keyboard, mallet
instruments, fretted strings), then this doesn't necessarily hold. In my
experience, most string players make a definite difference between enhar-
monics, or between playing with a piano and in a quartet. Nor does is this
necessarily true before equal temperament.

>My interest is barbershop harmony, which only works when the intervals are
>"correct", hence can not be accompanied.  It is fascinating watching a trained
>musician have to "unlearn" the tempered scale to make it work. 

Then more power to you. Tests done with a capella choirs have found that they
don't sing in just tuning systems, nor any fixed tuning system for that mat-
ter. (Many that I've worked with have trouble tuning with each other at all.)
Vibrato tends to obscure the tuning, as does the small (and sometimes less
small) differences between all singers on a part. If you found singers to
reproduce just intervals accurately, then congradulations.

Bill Alves
USC School of Music / Center for Scholarly Technology