[sdiy] UK meet up, intro, and a wavetable module plan

[David Evans]

On 11 Jul 2011, at 08:37, Chris Strellis wrote:

>>> Anyway, to the point! The chap with the grungy silverish wavetable
>> synth inspired me to think about something that I actually want to
>> build: wavetable VCO modules to be used with the Fenix. Here is my
>> rough plan:
>>> 
>> 
>> There are already a couple out there, so I think you'd some USP.
> 
> You could use this as inspiration?
> 
> http://postmodular.co.uk/motm/e350-morphing-terrarium
> 

I shall, thanks!

> P.S Great SDIY UK meet by the way but what was the pub fiasco? Apart
> from the unfriendly landlord at The Mill and The Granta being shut!

That was the fiasco I was thinking of. The pub should be effortless and pleasant!


On 10 Jul 2011, at 21:10, Paul Maddox wrote:

>> - A cool 16x8 LED display showing the current wavetable
> 
> I did like that, it was awesome
> 

It was great!

>> I'm thinking two of these. I'm uncertain whether each should have its own DAC or whether digital outputs should be available to a generic digital function module providing AND, OR, XOR, MAX, and so on. Thoughts? There's no analogue in this because I like the filters etc. in the Fenix; maybe later in life I'll make it more stand-alone.
>> 
> 
> I always wanted to try that, I'm not sure how musical it'd be.
> 

Nor am I, really. The idea is, mostly, to produce more harmonics for the filters to work with. I think that some "utility" wavetables, designed with this in mind, could be pretty handy.

>> Now, for medical reasons I can't really solder, so I'd look to build as much of this as possible in an FPGA and CPU so as to minimise the amount of work I need to exact from friends/electronics mercenaries. :)
>> 
> 
> FPGA?
> Doesn't need to be so complex, does it?
> 
> A small CPU ought to suffice
> 

Yes, though remember that I want to keep the parts count low and I might want to do other neat stuff later. The FPGA seems more like insurance than anything. Plus I've never built anything using one so it might be fun. :)

On 10 Jul 2011, at 22:07, Scott Nordlund wrote:

> 
>> - 16 or so wavetables of 16 samples each (8-bit is good since the goal is gunge)
> 
> 16 samples sounds too small to me. You'll only have control over the first 8 harmonics, and all waveforms will be very very buzzy. It's not a bad thing to use longer wavetables (unless there's some technical restriction limiting you to relatively low clock frequencies). You can always mask (or otherwise mangle) the address bits to lower the resolution.


Yeah, 16 is pretty low, agreed. Prototyping the thing in Max/MSP or whatever would give me a good idea of the sweet spot. My goal isn't really full sample playback. But it would be fairly easy to have the wavetable size be adjustable...not under voltage control but by rebuilding the software.


On 10 Jul 2011, at 22:12, Travis Thatcher wrote:

> I think its a cool idea - I've actually been working on a wavetable
> module design myself.  I'd recommend prototyping in soming like
> Max/MSP to figure out interface etc. Its really helped me out a lot.

Thanks, I plan to go down this road.

> Originally I wanted something with sliders, so you could 'draw' out
> the waveform, but that would make for some huge panels.

I played with this back in the 80s and it wasn't that great. The Technos Acxel lets you draw a waveform for each oscillator, but there you have heaps of them and can adjust their individual phases, so arbitrary waveforms suddenly becomes far more useful imo.

>  I'm really
> interested in morphing various wave forms with cv and coming up with
> good schemes to do so.  I hope to have a prototype done in a month or
> two.
> 

Cool, looking forward to hearing about it.

Thanks, all!