Analog Console

[absolom7691]

I also wouldn't go above 1500hz either. You don't want to fry your galvos.

[The_Doctor]

I think I can add a bit here. been experimenting along those lines a few years ago.. First, spot on about the frequency. About 1.5K is a good upper limit. 1K for WideMoves.Maybe 3 for CT scanners, but watch the scan angle, drop right back on speed before going wide. With scanners with spindly shafts like WideMoves, you get early warning of excess, in rough redraws, erratic broadening of scanned line. I'm not sure what warning you get with good scanners like CT6215, maybe not a lot, before risk of harm.

One thing a synthesiser might seem to have in favour is bandwidth limiting, but it's at way too high a frequency to be helpful here. I don't even know exactly how it works yet (but will, I need to for my synthesiser coding). You might use the filter of a synth, but the scanned line weight will likely be affected noticeably, and response may suffer too. Best idea is a slew rate 'generator' if the synth has one. Simple linear slew rate is a good protection for many things that don't like hard transitions. You may be able to add one based on an op-amp on the output of the synth. Some monosynths have slew rate generators on their LFO's, and are good candidates for analog scan control. Doeper's modules are especially worth a look. As is his 'Pocket Electronics' if you're using MIDI and designing your own control deck.

PS. Galvonaut, I thought I was the only Brit here to regularly keep these insane hours.

[CountFunkula]

I also wouldn't go above 1500hz either. You don't want to fry your galvos.

If you can hear your galvos "screaming", listen to what they're telling you

[Galvonaut]

Be sure to test on a vector scope before connecting scanners as you can kill them pretty quick using standard synths.

Thanks, I'll have in invest in a scope or two I think.

[Galvonaut]

I think I can add a bit here. been experimenting along those lines a few years ago.. First, spot on about the frequency. About 1.5K is a good upper limit. 1K for WideMoves.Maybe 3 for CT scanners, but watch the scan angle, drop right back on speed before going wide. With scanners with spindly shafts like WideMoves, you get early warning of excess, in rough redraws, erratic broadening of scanned line. I'm not sure what warning you get with good scanners like CT6215, maybe not a lot, before risk of harm.

One thing a synthesiser might seem to have in favour is bandwidth limiting, but it's at way too high a frequency to be helpful here. I don't even know exactly how it works yet (but will, I need to for my synthesiser coding). You might use the filter of a synth, but the scanned line weight will likely be affected noticeably, and response may suffer too. Best idea is a slew rate 'generator' if the synth has one. Simple linear slew rate is a good protection for many things that don't like hard transitions. You may be able to add one based on an op-amp on the output of the synth. Some monosynths have slew rate generators on their LFO's, and are good candidates for analog scan control. Doeper's modules are especially worth a look. As is his 'Pocket Electronics' if you're using MIDI and designing your own control deck.

PS. Galvonaut, I thought I was the only Brit here to regularly keep these insane hours.

I might have to practice on some cheap scanners! The bass is incredible on the Montron Delay, especially when you crank the VCF cut-off right down with plenty of delay, so should get some interesting outputs. I have a huge amount to learn about the intricacies of galvanometer operation before I experiment with this but it's definitely one for a rainy day/week/winter.

re. insane hours, I've had chronic/neuropathic pain for quite a while and often need meds to sleep and as I like lasers/rum/debauchery of an evening, often fail to take meds early enough!

[The_Doctor]

Ah, that makes sense. Anyway, whoever said the 'normal' life was the best use of time? It's actually pretty lousy for most things, and apparently archeologists are debunking a lot of notions about how people lived, or were 'supposed' to live...

To topic... Can't beat a good analog synth for solid broadband sound easily had ('FM' will definitely get you there but it's hard work without descovering how first). The two main tricks you're using to get that big sound might be a major hazard to scanners though. Resonance, and delay. With resonance up, the filter will VERY easily put the scanners at instant risk of going the way of the Norwegian Blue. As in VOOM, with or without the 50,000 volts. Keep it right down when scanning, that way it will keep it safe, the filter will help then instead of threatening harm. Likewise the delay can reinforce certain frequencies hugely, and it's very hard to predict what, when and how much, because much of the time the relations of the numbers will be irrational, so keep the feedback low on the delay. Very low, even, but cautious exploration of delay is well worth a go. Same goes for feedback on effects not so obviously related to dela (and many are!), like modulated flanging, which with high feedback can make stunning sounds even with only a tiny noise signal as input to it, but is a scanner killer for sure, because almost explosive changes in signal strength can happen at arbitrary swept frequencies. One fast way to get ideas for safe sounds might be to get some ILDA frames and standard beam scans rendered as waves, and listen to those.. Once you sense the character required, exploring a synth might get rewarding fast.

EDIT:
Try a program called GoldWave. I think it's free, or at least cheap, and has an oscilloscope screen window. At the speeds you'll need, that will work well. What it probably doesn't do is let you put two channels into X and Y at same time, and that's the best use of all for a scope and a synth with scanning in mind.

[Galvonaut]

Yes, I've noticed this thing can self-oscillate pretty effectively too but it is quite easy to set the resonance to a level where the feedback is stable. As you say, it can be very unpredictable and a lot of my time is spent tweaking settings to keep a stable and enjoyable sound. Even then, a frequency can emerge seemingly from nowhere, which I am sure would hammer a set of scanners!

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

[Randomseed]

Now I want to know what a quadrature sine generator would 'look like'.
I'm guessing its beautiful.

Seriously guys how are you actually interfacing between the modular and the ilda connection?

[The_Doctor]

Sounds like you'll get it. Your description sounds like you're listening in the right way. Sounds like you've noticed how a resonance turned low can still hit hard if you tickle it with a a frequency closely related (Natural harmonic series, integer relations..) Which reminds me, you may get some fun pout of trying tuning scales, beating between oscillators. Specially if you can get pure tunings. Most synths can't though, will likely all be equal temperament. An FM synth will get you pure tunings, but only with sine waves unless you get into it a bit. Sine waves are good though, I've been considering that FM might be the basis for a great scan controller because with level scaling in sinewave modulation it can be inherently bandwidth limiting, so the potential exists for complex scan control safely even without a filter of any kind. Whether it actually looks any good I have no idea. Yet. I might try this if the urge gets strong enough.

[The_Doctor]

Now I want to know what a quadrature sine generator would 'look like'.
I'm guessing its beautiful.

Lissajous figures. Actually: A circle. But start gently detuning them...

About the ILDA, can't answer for others, my experiments were limited to plotting things in PCM wave data and focussing on sample rate, dwell time, etc. All put out of a DC coupled sound card straight to differential analog input on a driver board.