Thanks to both Hugo and Dave T. (did you ever notice there seem to be a lot
of MOTM owners named Dave) for their insights into the analog FM question. I
originally said that phase would need to be specified, but what I meant was
that the initial phase position would be exactly the same for each note on
event, but again I think Hugo's much more on track than me in terms of basic
predicability problems.
But I think Dave's much more on target regarding the bulk of such a system,
as well as the precision of all the other components in the FM loop (VCAs,
ADSRs, etc.).
Finally, I've found it useful to "tune" my LIN FM patches at their extreme
positions. This is probably quite obvious, but what I mean is (given a basic
ADSR controlling a VCO which then controls the LIN FM of a second VCO) tune
to get a good sound at the extreme peak of the ATTACK position, again at the
SUSTAIN position, and at the end of the RELEASE position.
JB
In a message dated 8/18/99 11:01:36 PM,
hugo.haesaert@... writes:
>Hi All !
>
>Methinks it's more the "wobble" in frequency that makes analogue less
>useful for FM . On an Oberheim Xpander one can do some weird fm
>tricks, like the bells n such, but the osc's are not stable enough to
>be predictable, so more "normal" sounds just do not happen . On the
>Nord Modular, where phase is not specified either, very good DX
>sounds can be done, but then, the osc's are digital, and won't move
>unless told so :)
>
>The Yamaha FM is in fact Phase modulation : the index into the
>wavetable is increased or decreased according to the modulation
>index, that is a scaled from an input sine . But this does amount to
>frequency modulation .
>
>My 300's are not built yet, so we'll see when they are ;-)
>
In a message dated 8/19/99 4:01:00 PM,
improv@... writes:
>From: improv@... (Dave Trenkel)
>
>>From: Christopher Jeris <cjeris@...>
>>This is kind of a left-field thought, but has anyone (possessing more
>>oscillators than I) tried using MOTM VCOs to make Chowning/Yamaha-style
>FM
>>patches? All the old books say you can't do FM synthesis with analog
>>VCOs, but maybe a MOTM-300 is precise enough to pull it off?
>>
>Using my 300 and (highly controversial) Doepfer A-111 osc.'s I've gotten
>some pretty convincing 1-operator DX-ish timbres. However, you'd basically
>need 12 osc's, adsr's and VCA'a to really do DX-style FM (2 apiece for
>each
>of 6 operators), I'd rather just use my TX-416, which I got for just a
>little more than the cost of 1 MOTM 300...