MOTM

From Grant Richter!  This is very interesting IMO...

Hello All,

John Blacet and I are conspiring to bring a relatively inexpensive wavetable
module to a modular near you. I could not make enough of them by myself, and
John has kindly stepped in to make them available to everyone.

It can be driven with any ascending sawtooth VCO to add a 256 (or more)
waveform wavetable. It is appropriate to synth-DIY because it is an open
ended hardware device reconfigurable by software EPROMs. The development
software is downloadable from the Wiard site. Any waveform editor or Plugin
can be used to help make wavetables.

It also functions as a scale quantizer and non-linear wave multiplier.

http://www.blacet.com

EPROM programmers: Needhams USED to make the cheapest EPROM programmer at
$139, Model PB-10 has been discontinued. It worked superbly and never needed
replacing, therefore it had to be killed.

http://www.needhams.com

For development: I use a "Romulator" or RAM based EPROM emulator that will
plug into a 27C512 socket but can download from your PC (a good 486 app) I
use a model EE-512 from the stone knives (1996) era. Currently 5 generations
ahead the EconoROM 3 is a nifty device for any EPROM user and will work with
a Mini-Wave.

http://www.tech-tools.com/er3.htm

I have a fair collection of Wavebanks for the Mini-Wave. The surface has
been barely scratched.

A little background math. The Mini-Wave uses a 256 byte waveform. At a
sampling frequency of 44.1 Khz this corresponds to a 5.8 millisecond sample
at a frequency of (44100/256) = 172.26 Hertz. Any instrument to be sampled
should be sampled at that frequency. Use Sound Forge, Gold Wave and all your
plugins to manipulate the sample. Then store as a 8 bit raw PCM file, make
sure it is longer than 64K bites. Then use Move256 from the Wiard site to
open it as the "From" bank, open the target bank as the "To" bank and scan
along the "From" waveforms until you find one where the zero crossings line
up. The move it to the "To" bank. Viola, sample ready for Mini-Wave EPROM.

Previous 8 bit wavetable oscillators (Digisound VCDO, PPG Wave 2.x, Prophet
VS, Korg DW-8000, Ensoniq ESQ-1) used between 32 to 1024 bytes per waveform.
The larger waves can be resampled to 256 and two copies of a 128 byte
waveform will fit in 256 and preserve the sound quality. Some creative
resampling would allow use of the Ensoniq Mirage waveforms also.

Sampling system assume the sample rate is fixed. When you alter the sampling
rate, the math goes wacky and aliasing is inevitable. 256 bytes provides
less problems than 128. Think of it as sampling rate, 128 byte corresponds
to a sampling rate of 22 Khz. 256 bytes corresponds to a sampling rate of
44.1 Khz, so the larger waveform can be transposed further before aliasing
frequencies show up in the spectrum. But part of the sound of the PPG and
such IS the aliasing!

I really hope everyone has fun with this. It is an reasonably inexpensive
module with great capabilities. Additional enhancements are going to be made
to Wave256. The plan is to add Tschebychev polynomials with harmonic
sliders. You program the desired harmonic spectrum, and it generates a
non-linear transfer function that will convert a unit sine wave into that
spectrum (for non-linear synthesis).

Thanks again to John Blacet for making this available to the public.

Grant Richter
Wiard Synthesizer

> From: John Blacet <blacet@...>
> Organization: Blacet Research
> Reply-To: blacet@...
> Date: Fri, 09 Mar 2001 17:27:20 -0800
> To: grichter@...
> Cc: harrybissell@..., keithw@...,
> synth-diy@...
> Subject: Re: [sdiy] Miniwave EPROMS
>
> If enough guys send in stuff, maybe we can have Grant make a "Best of"
> EPROM???!!!!
>
> Any recs on handheld  PROM programmers?
>
> My perfect one would program pics and EPROMS and would hook up to my
> iMac! (Whot a dreamer...).
>
> Well, I guess it could just be handheld.
> ___________________
> John Blacet
> Blacet Research
> http://www.blacet.com
>
>
>
>