Theo Verelst Synthesizer Company CV

This letter I sent to a synthesizer company who asked me to present my CV in email form recently.

(heading removed)

I would like to present you with some more information in email form, 
not after adding that it is hard to include all the background
that is present on my web pages, and that I've left out non-synthesis 
related subjects.

I am an electrical engineer from the University of Delft (Holland), 
and have at least 15 year of active electronical and digital design 
and implementation knowledge, and about 20 years of the same of 
computer experience, hardware and software.

At university I have had a main emphasis on computer graphics, both 
during my graduation as during an added 4 years of work in a 
computer graphics project where the goal was to implement a specialized 
parallel hardware machine, composed of custom and programmable chips, 
combined with DSP's and linked with a fast (set of) workstations,
where I focussed on the design as a whole and implemented a working 
parallel and distributed simulation of the hardware, prepared a 
formal design and simulation environment to efficiently support complex 
designs like this, and wrote a lot of graphics and related software.

My experience areas and computer language knowledge include:

- design and implementation of a variety of extremely low budget
  and electronical music instrument building blocks, including a fully 
  home engineered and built mixed analog / digital design synth,
  of a fully polyphonic generator set (top octave synthesizer with
  dividers), combined analog mix amplifier/VCA/VCF unit with overdrive, 
  sine wave lfo for modulating HF generator and VCA/VCF, ADSD
  and a trigger unit/envelope follower fed from the mixing rail,
  as a noise gate trigger. Did this about 15 years ago on a budget of
  $100,- by having a nively shaped wooden cabinet, making my own
  using spring wires and silver ended contect tips, and using as cheap
  possible parts, because I had to do it on my (mid-highschool)

- A analog BBD based delay line with variable rate lf sine modultated 
  delay time as a choros/lesly unit, later I added a self-designed OTA 
  bssed compandernouround it

- I built my own design high quality mizer, a powered mixer and several 
  power amps (up to 2x70W)

- experimented with analog/digital rithms units and made various
  rythm boxes with them using ttl logic programmable driver modules

- some 20 years ago designed and implemented a shared memory/dma based
        multiplexed display and IO unit, based on discrete cmos
  small static memories, and 16 7 segment LED displays, meant to be
  with my own 8080 processor card, which was alleviated by my having 
  access to a trs80 clone.

- based on a 2 MHz Z80 trs80 clone I wrote lots of software, and added 
  various types of hardware, amoung which da/converters, 

- various simple sample recorders, and a variable length software 
  audio delay line

- sample playboack "dsp" routine for a 2MHz Z80, based on fixed point 
  variable increment (non-interpolating) looped  table lookup

- pitch follower software alternated with sample playback, driven by 
  my synhesizer extended with an envelope follower and with pulse 
  lenght measurement hardware

Around the time of starting at university (1984-) and later:
- trs80 based graphical  sequencer, (seriously !), with coupled machine 
  language code to produce duophonic additive synthesis based music
  over a 8 bit DA converter sampled at about 8kHz (+ filter),
  or drive a home engineered MIDI interface

- midi "out" interface based on discrete ttl components, angineered
  empirical data (couldn't get the protocol docu, so I borrowed an 
  oscilliscope and figured the protocol out myself)

- 68000 machine language programs, amount which sample playback
  at higher sample rates, also unter midi control

 - circuit analysis program using complex matrix solver with
spice-like input      parser and graphical output, on an Acorn
electron works very well to 
   in interaction-time produce graphically represented filter transfer 
   functions for active but linear moderate complexity circuits.

 - Various types of UNIX/C software for a range of applications, 
   amoung which Atari ST versions for interaction time rendering 
   of rational Bezier surfaces (3d order doubly curved patches), 
   and produced a range of UNIX compatible CAD and graphics 
   design and output programs

 - a fast switching, generally useable, non-preemptive multi threading
frame,      with very fast socket-type interface inter thread

 - a "connection server", which allows for socket based communication 
   between unrelated processes, dynamically recongfigurable e.g. 
   recompiling and reconnecting modules in run time, 
   completely transparent transfer also for distributed links, 
   no infringement on intrinsic socket speed for local sockets, 
   very easy to use (only small library for clients, prototype 
   graphical tool for generating communication C code)

 - a decoupled graphical interface with intermediate ascii form
command          interface for a chain of programs (CAD, radiosity,
raytracing, harware 
   rendering simulator image display, and distributed processing
   all based on the above communication package

Recently I've prototyped:

 - 4 pole (24dB/oct) resonating until oscillation voltage or digitally
            controlled analog sampling based filter (25Hz-25kHz range,
but only             prototyped with linear voltage control), various
interesting sounding 
   non-linear extensions...

 - 40 MHz Z80 card with high speed low cost multiplying (discrete
   da, keyboard interface and afore mentioned display card

 - designs for da/ad circuitry suitable for multi channel application

 - fast (o(1MHz)) SH/integrator prototypes

 - processor (Z80 "breadboard" version, running at up to 40 MHZ!)
linked with:     (Acorn "BBC") electron (shared memory), a large piano
type keyboard, midi       interface both in software version and in
above hardware version)
 - some switched supply , dc-dc converters and analog power amps, and 
   pwm modulated high power drivers (up to appr. 100W) based on 
   power MOSFET's.

 - made a physical modeling "waveguide" module running (real time for 
   e.g. 128 nodes) on a 100 MHz Pentium, featuring any number 
   (tried up to 8k, then sampling noise becomes too prevailent, 
   no wonder for a 16000 pole filter..) of 
   2 pole coupled harmonic oscilator modules, with ring feedback or 
   suspended on both ends with filtered end points, 
   programmable initial state, and prepare to contain non-linearities 
   in the transfer and oscillating functions (at the expense of speed).
   Experimental, but already producing (32 word width intermediate, 
   16 bit output) samples.

I've experiene with the following computer languages:
Basic, (UNIX and PC based) C, Objectie C, C++, Pascal, Z80 and 68000
code (assembly), Lisp, Tcl/Tk, Java, Html,

and programming and extensively using the following synthesizer
DX7 and TX802, Roland HP3000s piano, REV-7 reverb, RX-15, Bit-one 
and DW8000 analog/digital synths, Poly 800, TG500, used and 
programmed various samplers and all types of music software

I've written an extensive DX7 patch librarian with graphical interface, 
extensive and fast sound search and comparison facilities, MIDI 
processing, including graphically editable velocity curve transform,
remote control, and a "uniqifying" library maintenance system. It has 
been commercialized and generated appraising professional users.

It has been a long standing desire of mine to work in a US (preferably 
Silicon Valey) based environment.

I would like to again point to my internet pages for some additional

and will be happy to provide additional information.


   Theo Verelst.