[sdiy] "Synth design questions" or "Learning from Dave Smith"

jure zitnik kokoon at gmail.com
Thu Oct 18 13:43:01 CEST 2007 

about the scale - i have a couple of 2x40 lcds at home and there's
certainly enough room to fit 4 pots on the long side, even 5 or 8. the
reason i'd choose 4 is that you'd get 10 characters per parameter (it
could be 9 for the data and 1 blank for separation). i think that's
definitely enough, the descriptions don't need to be as detailed and
long as in my example. and as far as the update speed - from what i've
seen of the midibox stuff (where i got my idea from), it's not really
an issue.

check out this midibox seq video, and you'll also get the feeling
about the dimensions. imagine just 4 knobs instead of 8, there would
be plenty of space for nice big comfy knobs and still enough space for
twiddling them.

http://www.youtube.com/watch?v=bgjET6dNA14&eurl=http://www.ucapps.de/midibox_seq.html



On 10/18/07, Edward King <edwardcking2001 at yahoo.co.uk> wrote:
> Jure,
>
> I think thats a grand idea. Personally, I wasnt able to go with that
> approach (my problem was displaying sufficient data for each channel in a
> mixing type setup, rather than parameter display).
> but I have gone with a similar approach for the data / jog wheel where the
> parameter that its currently pointed to, needs to be displayed on a 4 x 20
> lcd, just in case you lose track of what you're editing, where it is and
> accidently alter something you didnt intend to.
>
> Have you drawn it out to scale on your pc for a rough idea of readability? I
> only ask because it doesnt take much to make character lcd's look "crowded".
> The other issue is that they're not the fastest devices on the planet, so as
> the update speed increases, the readability is reduced quite quickly.
>
> EK
>
>
> ----- Original Message -----
> From: "jure zitnik" <kokoon at gmail.com>
> To: "Edward King" <edwardcking2001 at yahoo.co.uk>
> Cc: "synth-Diy diy" <synth-diy at dropmix.xs4all.nl>; "Tom Wiltshire"
> <tom at electricdruid.net>
> Sent: Thursday, October 18, 2007 12:48 PM
> Subject: Re: [sdiy] "Synth design questions" or "Learning from Dave Smith"
>
>
> > i've also been thinking about the pots/encoders question recently. i
> > kinda figured out quite a cool interface using 8 endless pots (what
> > alesis ion uses if i remember correctly) or even rotary encoders PLUS
> > a 2x40 LCD display. multiply that as many times you want.
> >
> > it would look like this - there are two rows of 4 pots/encoders, one
> > above the lcd and one below. the display has 2 rows of 40 characters
> > each, which means 10 characters of text/numerical representation of
> > the parameter that the pot/encoder controls. i hope you can imagine...
> > for instance, you could have (should be viewed with monospace font,
> > just copy it into a notepad on windows):
> >
> >    O         O         O         O
> >
> > VCO1 tune VCO1 fine VCO1 pw   VCO1 morph
> > ENV1 att. ENV1 dec. ENV1 sus. ENV1 rel.
> >
> >    O         O         O         O
> >
> >
> > when each of the pots/encoders move, the display shows value instead
> > of name of its parameter. you don't need to see the name of the
> > parameter while you're tweaking it. there could also be a dedicated
> > 'disp' key near the lcd, that would toggle the idle display mode, or
> > it could be just a momentary switch to show the parameters' values
> > instead of names. or you could simply use the inverted character
> > (light on dark instead of dark on light) mode to graphically represent
> > parameter's (approximate, 0-10) value and still show the name at the
> > same time.
> >
> > this way, you can stack a few of such combos on a synth, two of them
> > would also make a nice sequencer interface...
> >
> > what do you guys think?
> >
> >
> > On 10/18/07, Edward King <edwardcking2001 at yahoo.co.uk> wrote:
> >> Tom,
> >>
> >> if you're likely to continue to expand on your system and possibly
> >> include
> >> polyphony and more complex audio engines, I would look at a digital
> >> interconnect solution with reasonable bandwidth.
> >> Bandwidth gets eaten up pretty quickly for realtime control and if you
> >> are
> >> likely to expand on your system, you'll lose nothing by jumping in sooner
> >> rather than later...
> >>
> >> My protocol specs and designs are pretty much ready for implementation
> >> for
> >> lower speed stuff (still a little work for the higher speed serial). Ive
> >> called it Simple Time Critical Audio Protocol and its an 8 bit
> >> addressable
> >> packet switch system. Given that its unlikely to be hosted on a system
> >> needing more than 255 devices, it should be okay for playing around with.
> >>
> >> Is there room on your devices for drivers etc?
> >>
> >> EK
> >>
> >> ----- Original Message -----
> >> From: "Tom Wiltshire" <tom at electricdruid.net>
> >> To: "synth-Diy diy" <synth-diy at dropmix.xs4all.nl>
> >> Sent: Thursday, October 18, 2007 1:28 AM
> >> Subject: [sdiy] "Synth design questions" or "Learning from Dave Smith"
> >>
> >>
> >> > Hi all,
> >> >
> >> > I've been looking at the very interesting guts-out photos of the new
> >> > DSI
> >> > Prophet 08:
> >> >
> >> > http://prophet5.org/prophet08/
> >> >
> >> > I'm always very interested in this kind of thing since it allows me  to
> >> > see a little of how other people have tried to solve design  problems
> >> > that
> >> > I'm looking at myself as part of my monosynth project.
> >> >
> >> > Before I mention that, I'd just like to point out the RJ11  programming
> >> > connectors for each of the processors on the voice board/ main board -
> >> > custom firmware for your DSI Prophet, anyone? The mind  boggles!
> >> >
> >> > Ok, now my questions:
> >> >
> >> > 1) Should the main control processor talk to the voice board  digitally
> >> > or
> >> > using control voltages?
> >> >
> >> > Originally, I thought I'd use control voltages, since it's simple and
> >> > keeps the analogue spirit of the voices. I had this in mind when I  did
> >> > my
> >> > PIC-based LFO and ADSR designs.
> >> > However, it does seem a little bit daft to have one processor take
> >> > digital information (patches from memory) and use an D/A to convert  it
> >> > to
> >> > a control voltage, just so that another processor (say, a PIC- based
> >> > envelope generator) can use a A/D to convert it back to a  digital
> >> > parameter. Consequently, I'm currently wondering about using  a SPI
> >> > connection instead.
> >> >
> >> > 2) Should the front panel of a programmable synth use pots or rotary
> >> > encoders?
> >> >
> >> > Again, originally I'd thought pots. This works reasonably well whilst
> >> > you
> >> > have a individual pot for each parameter, although even this is a  bit
> >> > of
> >> > a pain with a programmable synth, since as soon as you change  program,
> >> > none of the knobs tell you anything. When programming my  Korg Polysix,
> >> > I
> >> > always have the 'manual' button pressed, so that the  sound I hear is
> >> > the
> >> > one I can see on the panel. And that's a simple  instrument.
> >> > However, it would be nice to have multiple LFOs or envelopes that
> >> > share
> >> > controls, since this gives much more flexibility without making  the
> >> > panel
> >> > enormous . The Prophet 08 is an example of what I have in  mind - its
> >> > four
> >> > LFOs share the same group of controls, with simple  buttons to select
> >> > which one to edit. The trouble with this is that as  soon as you switch
> >> > to
> >> > the next LFO, the knobs don't tell you anything  again. Given that they
> >> > don't, are rotary encoders easier to work with  since you can just pick
> >> > up
> >> > the value from where you are without  having to worry about the end of
> >> > the
> >> > track? As a technical issue, how  does one go about monitoring 64
> >> > rotary
> >> > encoders?
> >> > So far, I feel the only really convincing solution to this is  encoders
> >> > with LED rings like Clavia use, but resolution is a problem,  so you
> >> > still
> >> > need a LCD to see the true value, although the lights  might give a
> >> > nice
> >> > guide. Also, building a serious synth panel with as  many knobs as the
> >> > Prophet 08 has would require some serious number of  LEDs, and
> >> > similarly
> >> > serious amount of current to light them all.
> >> >
> >> > At one point, I'd made decisions about many of these things, but as I
> >> > learn more, I keep finding more sophisticated ways to do things, and
> >> > then
> >> > wonder if the earlier decision was really so wise in the light  of the
> >> > new
> >> > information. I guess I should just get on and build the  simpler
> >> > instrument I designed originally and save the clever stuff  for the
> >> > Mk2.
> >> >
> >> > Thanks!
> >> >
> >> > Tom
> >> >
> >> >
> >> >
> >> >
> >> >
> >> > _______________________________________________
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> >> > Synth-diy at dropmix.xs4all.nl
> >> > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> >> >
> >>
> >>
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