[sdiy] analog pitch shifter circuit? more shifter thoughts

[Kenneth Elhardt]

synthplayer writes:
>>I was wondering if anyone know how does the boss voice transformer achieve
the voice pitch shifting? I would like to build an analog pitch shifter does
what the Boss voice transformer do but I am not sure if that is an analog
circuit,<<

There's no practical way to do that kind of pitch and formant shifting in
analog.  It's digital, and one doesn't need to open the unit to check.  That
same effect was also available in the BOSS VF-1 effects unit.  And if you
want it with multiple voices, vibrato, portamento, and controlable from a
keyboard, the TC Helicon series will do it.  I bought their Quintet a few
months ago and it's very fun.  As usual, I can't find the link now, but the
TC Helicon people have a webpage telling in general how they do it.  It will
involve FFT's at some point to separate formant info, and then they use a
pulse train to apply processed or shifted formant onto at whatever pitch
they want.  Something like that.

>>I would love to go out and buy a kit or the boss pedal itself, however I
am looking to build a rack unit and it just feels like a waste(not to
mention terribly expensive) to buy serveral Boss pedals just to gut them for
my DIY project.<<

Dare I point out the effeciency of simply buying rack unit versus spending a
lot of time to build something much inferior.  If your main goal is to DIY
something because that is fun, but you don't care if it sounds like crap, I
can't help you.  If you want quality and flexibility there are a number of
units you can pick up used and you don't need to buy multiple units.  The
Roland SE-70 can give you 12 simultaneous pitch shifted voices.  The Boss
SX-700 can give you 4, but it also has a mono input mode where it will
recognize the input frequency and use that in its window calculations for
better quality pitch-shifting without the metalic quality.  The Roland VP-70
also does 4 voices of pretty good quality pitch shifting on a mono input.
Or you can buy a TC Quintet, if you want Boss VT-1 type effects but with 4
voices.  There's lots already out there.  DIY isn't good for everything.

-Elhardt