From: drp40@cd.amdahl.com (Douglas R Puchalski)
Newsgroups: alt.guitar
Subject: Pitch Shifter/Harmonizer info
Date: 20 Aug 92 21:13:24 GMT
Reply-To: drp40@cd.amdahl.com
Organization: Amdahl Corporation, Sunnyvale, CA

Octave: Cheap effect, available as a pedal.  Does an OK job of raising or
lowering a note an octave.  Important to note that it will not work with
chords.  Single notes only, or you get major glitching.

Pitch Shifter: Generally describes a "parallel" pitch shifter, which uses
DSP to change the pitch of an input signal by a given number of half-steps.
So for example, if you're playing diatonic scales, the 7th note (assuming
ionian or major) will give you an incorrect 5th harmony since it's fifth is
a tritone and not a perfect fifth.  Obviously, then, for this reason, 3rds
won't work very well, so you can't get "real" harmony.  Musically speaking,
then, a parallel pitch shifter doesn't do much for you other than create
an "effect", but it cool if used with octaves (works with chords!) or fifths,
especially when you use the effect more subtly.  The best pitch shifter that
I have played with is on the Boss SE-50, which, in one of its modes, allows
you to produce 4 (!!) independent pitch shifts, and allows you to set the
delay -- longer delay produces a better sounding/more accurate version of
the shifted note.  This sounds excellent with single note guitar runs, and 
is especially good to make your voice sound like the devil for prank phone
calls!  Parallel pitch shifters are available in pedal form (Boss, ~$150?) 
and in many rack mount effect units, including the SE50 ($500+).

Harmonizer:  Ahhhh, the Evantide Harmonizer.  You've heard it on Steve Vai's
albums, as well as Joe Satriani's and others.  All the bad boys have one of
these toys.  There are a few versions, and they start at roughtly two grand,
and go up from there ($4k?).  I personally haven't tried one, since it's too
expensive more most music stores to stock.  But I would easily buy one if I
had the money.  Now, a harmonizer does just that.  It will truly harmonize
your playing in the correct key.  So you obviously have to tell the unit that
you're playing in, for instance, C minor.  Then it will listen for your input,
determine it's pitch, determine then, based on the pitch and the scale, how
far to shift the note's pitch.  The effect: a true harmony of your original
note, correct to scale.  I understand that this toy also does great things,
like feeding back shifted signals into the input to produce all sorts of wierd
effects.  Check out Passion & Warfare by Vai--all the wierd stuff on there
is from the Evantide.  And Steve said that most of the parts are very simple,
yet the Harmonizer takes over and jazzes up what he does to get the end effect.
BTW, once you've heard the Harmonizer and recognize it, you'll start to hear
it wherever it is.  There's still the "digitalness" of the effect, although
it sounds great.  And the difference between two guitars doing harmony and the
box doing it is that it will be *very* tight!  But it wouldn't surprise me if
there would be an option to randomize things a bit to make it sound more 
human.

-- 
Doug Puchalski						drp40@cd.amdahl.com
Newsgroups: alt.guitar,alt.guitar.tab,rec.music.makers