MOTM

> Does the two quadrant multiplication result in a different sounding output
> than four quadrant multipliers?

I asume we're talking RM made directly (4Q) or being composed of a 2Q
mult and a linear combination of the two input signals. (2Q mod aka VCA
does have completely different features, of course).

I do not expect these two methods to sound much differently. Nor would
the 3rd option, a 1Q mult and even more involved linear combination of
input signals, sound much different. (The MS-50 does this, and a similar
circuit is in Barry Klein's Book.)

In short, you won't notice a sonical difference between a 1496 or a 3080
when
both work in a 4Q circuit, and in their linear region.

But there are other 4Q circuits which have a "gap" in their linearity for
at least one input. They are working like a Class C amplifier (no quiescent
current) so you have a tiny threshold before they start to conduct.
I never actually heard one of these (so this is speculation), but I know
that
ARP used them, and most probably Emu, too, and I can imagine that such a
circuit behaviour results in a more "harsh" sound, especially at low levels.

Why would anybody do such a thing ? It's an elegant way to avoid bleedthru
trimming !! Just to make things more confusing, this feature - no
bleedthru -
is expressed by some as "clean", too. But in the very opposite sense of the
word ...


Two more remarks:

The CS-50/60/80 can crossfade from straight to 100% 2Q modulation to 4Q RM.
It's fun to do this while playing, especially because the the apparent
modulation
rate (in LFO range) doubles from 2Q to 4Q. Before anybody cries for such
an extraordinary feature - it works with *every* RM and crossfader.

When I have expressed my conviction that direct 4QM (1496 et alt.) and
composed 4QM (2QM with VCA, plus linear combination) are just the same,
I was talking about linear operation. Overdrive is a very different topic
altogether. But this can also be switched in externally, can't it ?

JH.