Analog Console

[The_Doctor]

Great idea regarding the ILDA paterns as waves. It might save me a few sets of scanners!

On that subject, it could be worth getting a wavetable synthesiser, and loading it with ILDA frames. My own work (PhaseMod, an 'FM'/analog/wavetable hybrid) was recently changed with this in mind, but I'm not sure how practical the reverse is. Original wavetable synths only had 61 user-settable cycles per table, and probably not many samples per cycle either. And maybe only 8 bits per sample, too. PhaseMod won't be doing scan control (but will use the wavetables as usual for such a synth). I talked about that to Buffo, but the upshot was that while similar, needs for bandlimiting are sufficiently different in sound and scanning that it's best to make dedicated tools.

[Randomseed]

So cut the end off of one of the output cables and connect to the driver.....
No if I only knew a bit more about the driver boards...time to dig.

You guys are all over the two biggest loves in my life right now.....just the fact this conversation is happening makes me one happy camper.

Thinking about it a little.....the ilda connection is analogue so it should be pretty easy to wire up a modular to ilda interface board with input plugs for the important modulations (color, x/y).

[Galvonaut]

Gosh - a few things are coming back to me from my amateur radio days (more of a pirate if the truth-be-told)! FM sounds like a fantastic idea especially creating harmonics. I wonder if it could sound good too?

What does a quadrature sine generator do? Is it like phase modulation?

[The_Doctor]

So cut the end off of one of the output cables and connect to the driver.....

Ouch! Dsub25's are cheap. Could do worse that cut an old printer cable in half and probe pins to find out which wire is which. I have never explored the ILDA cabling protocol, but I suspect it needs up to 12V for scanning signals. Likely differential too, same as a pro sound card. (On which subject, I recommend Layla 24/96 with WDM driver for low jitter, rock solid repeatability in fast scans, and the +4DbU (as opposed to 'domestic' -10DbV) signal levels will gove you up to 13.5V with enough control to finely set that as you need, AND set sample rate in increments of 1Hz anywhere from 8KHz to 96KHz, which will neatly match any scanner ever built for laser shows. But when it comes to ILDA hardware and protocols I know nothing, Señor...

[The_Doctor]

Gosh - a few things are coming back to me from my amateur radio days (more of a pirate if the truth-be-told)! FM sounds like a fantastic idea especially creating harmonics. I wonder if it could sound good too?

What does a quadrature sine generator do? Is it like phase modulation?

Nope, not quite, just detuning, though it IS modulating the phase, in effect, but in reality, frequency is being modulated in detuning, just by a fixed offset. Actual phase modulation is basically taking a copy of the underlying beat, so the carrier stays tuned, it's like rubato, the copy is is advanced or retarded by the controlling signal and the result is phase modulation. Frequency modulation for real would change the underlying frequency and it stays changed (and is not stable for frequency, or so easy to process at speed digitally, hence 'FM' not really being FM in Yamaha synths.)

Pirate radio? Now that IS cool. When Classic FM started I used to listen because there were no ads, and it ran all night. I spoke on the phone at some length one night to Sally Peterson, and learned that she had been in the Flying Lizards and was into punk, which of course was no end of cool. Also that Nick Bailey used to be on Radio Caroline, and that he wasn't the only one there who had! We had some fun with my image of Nick bailey flying in by helicopter like the Man from Milk Tray (They'd stated running Milk Tray ads around then, in the daytime I think). Anyway, it gave me a strong sense of just how interesting radio is, behind the scenes.

[Randomseed]

I have a digital 4 osc PM (Phase Displacement Oscillator)that is indeed (basically) pure phase modulation. All oscs are kept at the same turning (digitally) with modulation control over each phase separately. Favorite use is the classic barber pole sound (infinite rise/fall). Can even set separate waves for each osc.

On the FM side musically its generally used for metallic sounds or bells. When the freq rations are correct anyways, often time in dance music we ignore proper ratios and just start tuning to taste...really easy to land in fart sound land but there are many sweet spots...all freq ratio related (rational ratios sound much better, whole number ratios give the tuned metallic sound). Serveral of my analog oscs have digital sections for controlling the Fm and a I even have a duel osc that has a mode to actually force the oscs to stay in proper ratios (or close to them anyways) even while pitch tracking. The dr is very correct in that once you start FMing you are changing the fundamental of the original osc (often DRASTICALLY) but you can re-tune after the fact to get things back into scales if thats what you are after.


So onto signal levels Im using eruorack mostly which is +-10v on the signals so some kind of voltage scaler would probably be required I'm guessing.

[Galvonaut]

ILDA is +-10v for X Y and +5v per colour channel.
Handy link for you Randomseed

I'm am pretty much working on the ground up here as I did electromechanical engineering when I was 14 to mid 20s and have been photographer since 24 (now almost 40) so most of what I learnt has been buried under that (plus military training). Great to bring all of my previous skills together on something completely new though

Laser and synths are awesome Randomseed. A friend also does projection mapping and that's pretty phenomenal too. I like brain bending stuff!

[laserist]

snip
What does a quadrature sine generator do? Is it like phase modulation?

A quadrature sine osc. outputs both a sine and a cosine waveform. Hook one up to the x and the other up to the you get a circle. If you sum several together you have the electronic equivalent of the old spirograph toy. Invert one of the signals you change from drawing that circle clockwise to counter. Toss in amplitude modulation, frequency modulation and you can go places…

[Galvonaut]

A quadrature sine osc. outputs both a sine and a cosine waveform. Hook one up to the x and the other up to the you get a circle. If you sum several together you have the electronic equivalent of the old spirograph toy. Invert one of the signals you change from drawing that circle clockwise to counter. Toss in amplitude modulation, frequency modulation and you can go places…

Nice. Thank you laserist.

[The_Doctor]

I have a digital 4 osc PM (Phase Displacement Oscillator)that is indeed (basically) pure phase modulation. All oscs are kept at the same turning (digitally) with modulation control over each phase separately. Favorite use is the classic barber pole sound (infinite rise/fall). Can even set separate waves for each osc.

Shepard tones. Forgot about those... (Always makes me think of Alan Shepard, in orbit, rising forever.. Wasn't him though, some other Shepard I think). They could be useful. Not sure what the scanning equivalent might be at best, but it's a great idea. FM is sorely underrated, incidentally. You're right about the usual perception, but there are at least two easy departures from form that head right into the best sorts of sound you'll ever hear from a synth. Try carrier 1 to modulator 1 or two as freq ratio for saw and square respectively, use full feedback for modulator to itself. Set 'feed forward' as opposed to output level of modulator into the carrier, slightly less than full, like 6 instead of 7. An SY99 will do this, a DX7 won't. Tweak modulator phase a bit, and you get awesome analog waves. Tweak fairly high output level right, and you'll get nice bandlimited analog waves, even with no level scaling to correct the mod index for pitch changes, which makes this even better an analog than Yamaha's own AN1X! Single parameter changes can change to saw/square as I mentioned, and another I forget, probably phase setting in carrier, can invert the waveform, so long as key sync is switched on. More widely usable is detune with pairs of equal stacks, using high mod index finely adjusted. very rich wavetable sounds. Bit off-topic now though because those waves, while stronger than most other sounds, are so rich in harmonics that they'll just mess up a scan pattern. fart-sound-land is where we get to if we don't strongly control that mod index. And I reckon that low mod indices are where it gets interesting for scanners.