TB Sequencer Replication by Software (was another @#!! TB thread)

[Sean Costello]

At 10:30 AM 4/29/98 +0100, you wrote:

>However, as soon as I tried to recreate a 303 pattern using Cubase via a
>cv convertor (with slide...) the magic is lost. It's very difficult to
>get close to the feel of the 303's own sequencer. There are a few
>potential reasons for this that I'll be looking into sometime soon, but
>it suprises me how many commercial 303 clones there are and none with a
>cloned sequencer AFAIK.

OK, how DOES the sequencer work?  It can't be all that magical - the only
portamento control is a simple circuit marked "SLIDE ON/OFF" (for some
unknown reason, I have a large schematic of the 303 behind my computer here
at work.  I don't even like techno that much nowadays).  

Here's a guess at how the "slide premonition" works:

- The sequencer is divided into 32nd notes, with 2 32nd notes per 16th.
- When a note has a slide programmed into it, the first half of the 16th
(the first 32nd note) plays the note programmed for it.  The second half of
the 16th plays the note that will follow (i.e. the next 16th note in the
sequence).  The envelope only triggers for the first half of the 16th note
(unless it is legato, & doesn't trigger at all for the entire note).
- On the 2nd half of the 16th note, the "SLIDE ON/OFF" is triggered.  As the
slide is triggered at the same time as the new pitch is sounded, the
oscillator will slide up to the new pitch by the end of the 32nd note.

I may not have explained the above that well, so I'll come up with a
hypothetical example:  Say Note 1 is programmed to C3, and Note 2 is
programmed to C#4.  Note 1 has a slide programmed into it.  At the beginning
of Note 1, the envelope triggers, and the pitch sent to the oscillator is
C3.  Halfway through Note 1, a new pitch (C#4) is sent to the oscillator; at
the exact same time, the "SLIDE ON/OFF" is switched ON.  This causes the
pitch of the note to slide between C3 and C#4.  

Now, this seems like behavior that can be duplicated in software.  I haven't
worked with MIDI that much, but it seems that if portamento can be triggered
at will, then a sequencer can be programmed to reproduce this behavior.
Maybe someone can come out with a shareware 303 sequencer (like the
"Seq-303" sequencer I have heard about - isn't the author of that on this
list? I forgot who wrote it) that can automatically produce this behavior.
Or maybe I should get off my butt and do it myself.  I hope to take some C++
programming this summer, so maybe I can come up with some workable thingys.

Sean Costello

P.S.  I haven't worked with a 303 in real life, so these are just guesses.
Perhaps the division of the note isn't by 32nds, but is by some other factor
that would contribute to the "feel" of the slide.  Or maybe I am completely
wrong.