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Subject: Re: SV: SV: [AN1x-list] FM synthesis (long post)

From: Bruce Wahler <bruce@...>
Date: 2001-03-10

Jim,

>I still need to wrap my head around the syncing of vc01 and vc02, why one
>would chose one over the other for master-slave..

In principle, it doesn't matter which wave is the slave for syncing, but in
practice, once a VCO is selected, the waveforms of the two VCOs can be
pruned to include only the most musically useful ones. It may simplify the
design, which usually translates into a cost savings.

>One thing especially...when some of the algorithms have an option called
>"fixed" does that effectively turn the option off...out of the picture?

Fixed doesn't turn syncing off; it just fixes the frequency of the slave
oscillator. If we look at how syncing works, the master oscillator 'says,'
"Look, the slave oscillator can do anything it likes, frequency-wise, but
every time I reach the start of my waveform (0 degrees), I'm going to force
the slave back to 0 degrees, too." This is a kind of modulation, and like
other modulation types, results in a wave that has frequency components of
both the carrier and modulator. IMHO, fixed-frequency syncing is less
musically interesting than variable-frequency syncing, just like a sine
wave is less musically interesting than a sawtooth -- but that's a
generalization. Both sines and fixed syncing have their use, musically.

>I assume you've been here longer, and know about the list...but for the
>short time I've been here I have seen mail form other novices and I can't
>believe they would want to miss out on this kind of good explanation of
>theory, about one of the central modules.

Actually, I've only been on the list for about 2 1/2 weeks. My advantages
are: a) I'm an electrical engineer whose specialty is analog electronics;
and b) I was fortunate enough to go to a college in the mid-70s where I had
access to a Minimoog, a Putney VCS3, and a Buchla. The access to
non-programmed, analog synths means that I had to learn how to do things
from scratch, rather than depend on a library of sounds created by the
manufacturer. A pain in the butt then; a clear advantage now. When I
first got the AN1x, I spent a week of, "Wow! You mean you can sync the
VCOs to LFO1, and still have VCO2 left over???" and such.

>I certainly can take it off line...but isn't the purpose of this list to
>discuss exactly this kind of thing? Have most of the people here already
>been through this?

A good question for the group: Was my explanation to Jim useful to others,
or was it a case of, "Oh no! Not another round of synth theory!" I'm a
relative newbie here, so a poll might be in order.

>(by the way..any idea of the number of listers?)

~400


Regards,

-BW

--
Bruce Wahler
Design Consultant
Ashby Solutions"
www.ashbysolutions.com
CloneWheel Support Group moderator
978.386.7389 voice
978.776.0096 fax
bruce@...