Tuesday, 23 August 2016

Mini Oramics at Fort Process Festival

The next chance to get your hands on and play with Mini Oramics will be at Fort Process audio festival on the 3rd september. I hope to see you there.


Feature in The Wire

Mini-Oramics and an interview with me feature in the September 2016 issue of The Wire

Mini Oramics on BBC Radio 4

Thanks to the Goldsmiths press team, a BBC feature producer, Chris Vallance, became interested in my research, and he made a small web feature and a short piece for the World at Onewhich featured myself, James Bulley and Dr Jo Thomas all talking about Daphne Oram, Oramics and Mini-Oramics. I was able to point Chris to an old BBC sound recording of Oram herself talking about Oramics on the World at One in 1972, which made a lovely link into the piece. The audio of Oram talking about her work on the BBC is available at the Daphne Oram Archive and is audio archive number DO236.

I think the radio link has expired but you can see the web feature here.

Mini Oramics at Brighton Modular Meet

Another demo was at Brighton Modular Meet, University of Sussex.

Photo courtesy of Eden Grey

Mini Oramics at Seeing Sound

The first public outing of the Mini-Oramics system happened at the Seeing Sound Conference at Bath Spa University in April 2016.

As I had still not had time to write any music for it, I used John Lely's score roll to demonstrate the machine. Unknown to me he had craftily put a phrase from Kraftwerk's We Are The Robots at the end which finished off the demo nicely!

Demonstrating the machine at Seeing Sound, photo courtesy of Nuno Correia

Some Musicians Finally Get Their Hands On Mini-Oramics

The next week I brought the new machine into Goldsmiths for some artists to start working with.

John Lely started off proceedings and also helped me get it in tune properly! John was amazing and really expolored the boundaries and parameters of the device and will hopefully be working with Mini-Oramics again soon. Unfortunately I don't have a film of his initial work.

I then also had some short visits from some other musicians and made this short video:

Mini-Oramics early trials from Tom Richards on Vimeo.

I also worked with Ain Bailey, Jo Thomas and James Bulley and made this slightly longer video which started to appear on various other websites and blogs (mainly thanks to the Sarah and Phoenix at the Goldsmiths press team). James programmed a short version of Messiaen's Oraison which features at the end of the video. The work which was originally written for Ondes Martenot really suited Mini-Oramics.

Mini-Oramics Medley from Tom Richards on Vimeo.

First Tests

Mini-Oramics in my studio shortly after final assembly:

Once it was all finally assembled and connected I had to test and calibrate the unit.

It was pretty nerve racking, and even though I had tested all the circuits individually, it started out not working at all. As I was adjusting/calibrating all the graphic input comparators - which initially detect the pen strokes, it seemed as though there was a lot of interference. As I adjusted one input (of 72 in total) another one would go out of adjustment and 'detect' nothing at all. It was incredibly frustrating. It was very late at night by this point and also I had been accepted to demonstrate the unit at the Seeing Sound Conference only about a week later so I had a very tight deadline. I had also scheduled for some composers to come in and start using it in the Goldsmiths Electronic Music Studios the very next week. I had to give up and go home and sleep off the disappointment. Luckily however, the morning I had a slight hunch as to what might be causing the problem. It turned out the interference was optical rather than electronic, and I just had to move the IR LEDs closer to the sensors. It then started to function as intended. By the end of that day after some further adjustments, I managed to post this slightly amateurish demo video:

MINI-ORAMICS WORKING! from Tom Richards on Vimeo.

The final push - putting it all together.

In March 2016 I started the final assembly. I designed a front panel for the sound generator section in a standard 3u subrack type enclosure.

Also had to make some slight changes to the main framework of the machine to be able to fit a front panel to that.

Here are some pictures of that process:

Front panel made using Schaeffer AG front panel designer:

Assembling the final array of IR phototransistors:

Drilling out the other front panel:

Assembling the rear panel of the sound generator sub-rack unit. PSU / VCFs /and VCAs visible:

Starting to rebuild the programmer with circuitry inside:

The row of blue preset pots here control the 12 different volume levels available on each of the three envelope sections, the other circuit board is the motor and lightbox control circuitry:

Starting to install the graphic input modules:

Most of the circuitry connected together:

Some Initial Demos

Once I had built most of the circuits I did a couple of video demonstrations with the kit set up in an improvised fashion. This was around February 2016.

Much improved waveshaper with 16 steps and improved anti aliasing:
wave shape demo from Tom Richards on Vimeo.

System set up in improvised fashion and able to control pitch and waveshape only:
Mini Oramics Demo from Tom Richards on Vimeo.

Finalizing the other circuits

I still needed to transfer all the test circuits into soldered permanent circuit boards, and also design and construct some simple utility circuits for combining CV and audio signals.

These were:

  • Main VCO
  • 2x Multiplexer/Waveshaper Circuits
  • 2x Voltage Controlled Filter
  • 3 Channel Motor Speed Control (Drive / Wind / Rewind)
  • DC Mixer for combining the Pitch/Octave/Vibrato control voltages
  • VCAs and simple audio mixer for combining the two different waveforms and allowing for the spring reverb send/return. (I completely cheated on the spring reverb and just used a Doepfer modular unit. I had totally run out of money and time, and I already had this unit in my studio.)

Most of these I made on stripboard, except the waveshapers which I designed PCBs for. Some images below give the general gist.

Twin VCF circuit based on an R.A. Penfold design:

Multiplexer based 16/32 step waveshaper board:

Slider PCB for waveshapers:

3 channel stepper motor control for transport mechanism:

Monday, 22 August 2016

Turning drawings into control voltages

This part of the design took months and months. Turning felt tip pen drawings into digital logic is unfeasibly difficult! I went through about three or four prototypes on breadboard with varying degrees of success. I had a lot of very generous free assistance from Robin Iddon and Roger Dealtry, who coached me on the necessary logic and prioritisation circuitry through these experiments, and I got very close, but not quite close enough. I was trying out different types of flip-flop circuits: SR, JK, and D-type. Essentially I needed a circuit which would read and latch onto the last read input, but that would also reliably reset all the other inputs so that only one input would be 'read' at any one time. From there I could use analogue switches and resistor ladders to select and output control voltages, which would then be used to control pitch and volume etc. In the end I had to go back to the drawing board and old fashioned logic timeline graphs to analyse what was going wrong, and then what needed to happen instead, and finally the penny dropped and the optical reading circuits were born. I wanted them to be simpler with a reduced gate count, but as I had finally something working properly I just went with it rather than trying to make it less complex first. Once the circuit was working I took the time to design proper PCBs, as I would need seven of them for the final machine. This was by far the most complex circuit I had ever designed and also by far the most complex PCB design I had made, so I had my fingers firmly crossed as I switched on the PCB version for the first time. I had about three hours of exasperation as it just would not cooperate, and then I realised I had not soldered one tiny resistor which was essential for the start up process (a simple RC sub-circuit to overcome start-up glitches and to make sure the machine came on silent awaiting the first instruction). After fixing that, and a doing a bit of calibration on the optical inputs it finally worked. I made some small adjustments to the layout and then ordered one PCB for each of the input parameters of my Mini-Oramics machine.

The first optical reader PCB. The multipin header sockets connect to the phototransistor readers and also the indicator LEDs which allow you to monitor if the drawn inputs are being read correctly:

Last of the breadboard prototypes:

Improved Transport Mechanism

After I built Legoramics, and after building a few unsuccessful test logic circuits, I decided that I should prioritise building the final transport mechanism in order to be sure that any further circuitry I built would be made for the actual mechanical framework I was to finish up using. So I enlisted the generous help of Christian Nyampeta, as I am useless at CAD and technical drawing. Together we came up with the framework for the final machine, in which Christian's drawings were later transformed into laser cut perspex. The design was to use standard OHP cellophane rolls. I tried to design the machine to be mechanically simple, and capable of both 'reel to reel' and closed loop operation.

This is what we came up with:

Mini Oramics Transport Mechanism - first test from Tom Richards on Vimeo.

Transport prototype and initial light reading circuits

I then needed a way to test some initial light reading circuitry designs. I had yet to build the transport mechanism so I built a small lego prototype with four LED/ light-sensor pairs to test my initial logic circuits. I named this Mini-Mini-Oramics prototype Legoramics.

Legoramics from Tom Richards on Vimeo.