rcrds

i’m currently on residency at STRUTS Gallery in Sackville, New Bruinswick, Canada.

from Call & Response Festival.
i played a live set for video-projector and 8.1 sound-system

this cut is from the very start:
http://vimeo.com/16731102
filmed on a phone by Vasco (thnx)

http://www.kwag.ca/en/exhibitions/sciencefictionsciencefair.asp

okay maybe that’s half true.

‘blogging’ at any rate started to suck, mainly because of spam and catastrophic sever hacks/crashes. comments might be possible, but registration? not sure at this point.

but anyway, in the meantime i managed to put a few of these things together:
…not a ‘circuit-bent’ commodore… i threw out the mother-board and built a new circuit which makes use of the keyboard’s inherent touch-sensitivity. this thing outputs 800×600 VGA signals, consequent audio, and provides for the mixing and manipulation of whatever else you plug into it.

this machine dubbed afterbirth, is a performance instrument for some ongoing projects. it’s older brother called the long slow death of nostalgia (for some reason) got one performance before its induction into the museum system.

here’s my first assembly language project in the works:

i started with the program from here: http://yusoft.kulichki.com/english/pic/my_proj.htm

it didn’t work until i added the 555 part of this circuit in order to get the V-synch pulse-width right.

this spurred a rewrite of the program. this synched without the extra PWM stuff…
i added an extra output to function as a gate to control a 4066 switch for proper RGB blanking.

everything worked fine in the middle of the screen,
but the top of the image was skewed:

rather than try to fix this,
i moved on to making an SVGA 800×600 @ 60Hz program based on the timing info found here: http://tinyvga.com/vga-timing/800×600@60Hz (and some other details elsewhere)
this runs on a 20MHz crystal which, if you do the math = exactly 100 instructions / visible line and nice round numbers for all the sync and blanking periods.

for fun i followed up with a 1024×768 @ 60Hz version:

happily this program actually worked first try, however, the skewed image thing returned.
with a lot of tuning to the Vsync areas i minimized the skew to just a small bump at the top, but i’m not sure how portable this thing would be with less forgiving monitors.
for this version i also added 75ohm terminating resisters to the RGB outputs.

i’m thinking that the ratios between vertical and horizontal sync times have a lot to do with the skewing thing. so far, this last version looks just the same whether the the processor clock is running at 18, 20, or 17.7344 MHz.
the 800×600 version has at least all the correct ratios. so next step is to use this as the core of a new AV synth.

here’s a valve based preamplifier in the works.

those little glass envelopes can sure be fun… takes loads and loads of testing and tweaking at high-volume… but thankfully the neighbour has been pounding on the wall when the sound gets to be just perfect. (thanks bob.)

much of this stuff here has been salvaged from old television set and a bit of mysterious military transceiver equipment.

there were some bad buzzes in there… on 1 channel but not the other oddly enough…
…dedicated powersupply with more current and cleaner power for the heaters was in fact the solution.
so now it’s 2 channels with the good kind of quiet. (and the nice wicked-loud i should mention)

only one mighty shock from the dc power so far… felt a bit like a pysio machine…
not so bad for 350 – 400 volts actually…
but do remember kids, involuntary muscle contractions can be dangerous… so play safe, etc.

today marks the official launch of a little webforum dedicated to hacking around with analogue video synthesis.

http://vidisynth.mediumrecords.com/forum/

it’s been there for a few days, but why not pick an official birthdate? today is the 43rd anniversary of the first broadcast of Doctor Who … a show which was well known for it’s creative visual effects on a tiny budget as well as its neato psychological/sci-fi soundtracks. that’s a good birthday to share.

this is my first completed video-synthesizer.

it adds the wave-forms of audio inputs onto the VGA output of a computer.
it can be patched in ways which turn it into a big, fast, and very noisy audio-visual glitch machine.

more over on project-page>>>>>>>>>>>>>>>

info on project-page>>>>>>

here’s just another little video file.

http://www.mediumrecords.com/video/vidisynthexp05b2.mov 18.2Mb 3:13

was experimenting with different resolutions and refresh rates to drive the synth’s sync with. the basic circuit handles 120Hz (as in this example) with no problem and also works with all the other rates like 85Hz, 75Hz etc. higher rates actually do look better but it will be interesting to see what’s involved with converting to SD video.

resolution works fine at 1024 pix wide, but higher than that causes the right side of the image to be brighter than the left for some reason.

(not sure who this music is from at the moment as it was just taped off the radio… will be a bit of work to figure out who it is, so, that soon)