OK, I generalized too much. The "Roland Sound" that I'm thinking of comes from more
of the discrete designs. The filters in the Jupiter-4 and the System 700 have
something about them that says "Roland" to me. This is certainly different from
Moog, Arp, or SCI. The Juno-106 has a taste of this character but it is a bit
different yet very identifiable. I haven't spent enough time with a TB-303 to
classify it this way but I think most of us can pick it out when used obviously in a
tune.
I've got a good sequence for showing off a filter that I came up with to look at
Jurgen's questions about Moog filters. Perhaps I need to try this on a few other
filters and post the results over the holidays...
Eric
---
mark@... wrote:
> At 7:35 PM +0100 12/18/01, jhaible@... wrote:
> >
> >>I think there is something to the
> >> character of Roland filters that
> >> applies to all of them. That would be the "essence" that
> >> MOTM should be look
> >
> >Let me offer a slightly different conclusion:
> >
> >We have a variety of filters from Roland, OTA filters with
> >opamp buffers, OTA filters with FET buffers, Transistor ladder
> >filters, Diode ladder filters, integrated quad OTA / quad buffer
> >filters, and they ∗all∗ have "that Roland Sound"! If this is
> >true (and I'm not the one to decide this), then you definitely have
> >to look for an important factor which contributes to "that Roland
> >Sound", ∗other∗ than the filter circuit.
>
> I completely agree, and I would say that all of them do not have "that
> Roland Sound", unless you want to make the silly semantic argument that
> everything Roland has a Roland sound.
>
> >Let me make this clear: ∗Maybe∗ the Roland filter chip, which has a
> >very similar block structure as the SSM2040, has some yet unknown feature
> >which is responsible for a special sound. It's not entirely impossible:
> >Before I learned of the SSM2040's internal circuit, I also thought
> >"just another ota filter". So it's ∗possible∗ that the Roland chip
> >holds a similar (but different) secret. But is it ∗likely∗ ? I think
> >it's ∗unlikely∗ that it has a secret which it also ∗shares∗ with all
> >the other (discrete and disclosed) Roland filter circuits.
>
> It's more than unlikely that it shares this secret with all other Rolands
> -- I think it's downright impossible. However, the IR1309 might have a
> unique quality which is responsible for a special sound. In fact, it's is
> very likely. The question is: is it different enough to make a "clone"
> worthwhile?? I can't answer that question. Yet, if you would like to try,
> I have an IR3109 chip, and Juno 60, MKS-80, SH-101, and MC-202 schematics
> that I can send you.
>
__________________________________________________
Do You Yahoo!?
Check out Yahoo! Shopping and Yahoo! Auctions for all of
your unique holiday gifts! Buy at
http://shopping.yahoo.comor bid at
http://auctions.yahoo.com