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From: tak@hprnd.HP.COM (Tom Keaveny)
Newsgroups: comp.music
Subject: Re: vocal harmony question
Message-ID: <3160003@hprnd.HP.COM>
Date: 12 Dec 89 22:18:13 GMT
References: <19114@watdragon.waterloo.edu>
Organization: HP Roseville Networks Division
Lines: 57

/ hprnd:comp.music / dmnhieu@trillium.waterloo.edu (Duy-Minh NHIEU MAPLE tutor) / 12:02 pm  Dec  8, 1989 /

>Some music (songs) are written in two parts for a duet (usually they are a 
>major third
>apart), my question is why for some group of two people that perform the duet,
>it sounds harmonized and for other, it does not sound harmonize although they 
>sing in tune with respect to each others, does it have anything to do with the
>voice?  I mean the different timbre of the voice?  (Say a guy with a guy, a
>girl with a girl and a guy with a girl, which combination sounds the most
>harmonized?)  Is  there any technique to harmonize?  ie the relative volume
>etc...
>----------

One thing that affects the blending of two "voices" is the harmonic
content of each individual voice.  While you might be able to cleanly 
blend the two pitches of primary interest, the additional frequencies
may not mix so well.  In this sense, the more complex a voice is, the
more difficult it may be to achieve a pleasing harmony. Harmonics /
overtones may also come into play when the relative spacing between
the fundamentals is not precise.

The uniqueness or distinctiveness of an invididual voice is also
an issue, as those characteristics will tend to continue to stand
out when blending with other voices.  A similar analogy can
be made to other arts, such as dance. 
If you have ever seen the musical "A Chorus Line", consider how
the distinctive style of Cassie(?) tended to detract from the flow
of the troupe.

The "spacing" of the voices also comes into play, especially when
mixing male and female voices.  As voices become more separated
in frequency, the sense of "something being missing" in the mix
becomes more pronounced.  On the other hand, having voices that
are too close together in pitch may also sound dissonant.
(nothing like a straightforward problem, eh?...)
I gather there is some psycho-acoustic point
at which mathematics may say it should be harmony but our auditory
perception no longer realizes it.

The two singer  problem is a specific instance of the general problem of 
"voicing" any polyphonic piece of music, where the timbre of each
instrument in the mix must be taken into consideration, whether
it be a human voice, flute, violin, etc...

Too, just as some instrumentalists are more adept at blending their
notes with other players, certain singers can control their vocal 
chords and their resonant cavities to enhance the harmonizing effects.

If you'd like some interesting technical reading on the subject, I would
recommend:

	"Music, Physics, and Engineering", Harry F. Olson
	Dover Publications, New York, 1967

-----------
tom keaveny  (aka tak the hack @ Hewlett Packard:Roseville Networks Division)
tak@hprnd