CYGN-B

[Greg]

The 1/4" tape library has been completely brought over to the PC side, except for the walk in and walk out music that has no data.

I had the XT20 serviced a few months ago, so it is now ready to go for accessing the 8 track ADAT tape library.

A simple experiment I haven't done until now is to view the output signals of the ADAT player directly to an oscilloscope. The photo shows that great looking images are sitting right there. The distortion in the XY signals I observed last time I looked are obviously some problem in my code converting to 16 bit following transfer.

While listening to the voice track, there is frequent call for setting something called audiomod rotator. There are settings for this noted in the PIN files, excerpt shown. I don't see any reference to audiomod in the mark 6 main panel.pdf.

[lasermaster1977]

That looks terrific!

[laserist]

After my time, there was a mod to allow various rotations to be done a single axis at a time, and other weird things. Maybe it involved audio mod too. The controls were on the add on box the was above the console on the top left. That box went through several iterations by the way. I didn't use it - it was really dangerous in a performance sense for me. It wasn't remotely part of my muscle memory, so a screwed up setting was a disaster for long long seconds at a time in front of the audience. And honestly I didn't like the effects much.

[Greg]

Does the name Greg Weisman in the context of LII hardware development bring any recollections?

Unrelated, a minor gap in my understanding of the original system: where and when did signals from the oscillator banks get summed with the KQO?

[laserist]

I don't remember if I ever met Gregg Weissman. There's a Facebook post that says he was involved with Crystal Odyssey.

The upper/lower cage trilite switch signals were connected to summing amps on the cycloid rotator board. Right side of the schematic.

[Greg]

Thank you. I mention it because I detected a suggestion that that name is associated with contribution to the development of the Digital Offset Generator.


Summary for readers:
The DOG card, code ported earlier in this thread, for all it's weirdness and small memory map, was one of the many hearts of the 1980s era show systems. And by hearts, I mean 555s.

[Greg]

Thank you for posting those cycloid frequency ratios, Greg. Those are many of the same cycloidal harmonics that I store on my APC40 MIDI controller's preset buttons for each of the QOSC channels, then cross fade/mix between during live play/recording onto Reaper DAW's MIDI tracks.
I remember the basic octaves, from way back when, but your pics fill in many of the gaps in gray matter, plus more. Your generous sharing will save lots of explorations by tuning. Plus, you've given me the idea to add functionality for manually keying in relative harmonic frequencies, instead of only explicit frequencies from a Numkey pad.
You've also reminded me of the value of including AM offset sweeps, of which I'll need to add mappings & CV controls for.
Your awesome dev work, dedication, and end results are truly inspiring to behold, Sir.
Well done (as if it ever could be) & BR
Roj
😎

Thanks Roj. Here is one I found a few days ago: a 2d fishoid (term coined previously by Steve) swimming in a 3D space.

Update: Working on bringing the 8 track ADAT shows into my current system. Docs suggest the XY tracks enter through the ADIG. I see 352 frame bits 15,6 and 20,3 note something about the ADIG and Danube. My guess is that some combination of these bits would switch in the ADIG output into one of the Danube bus inputs, so the art from tape could enter the performance as an image source.

I don't know why the old docs refer to a "BUSS" rather than a BUS? Is it like how discussions of computer viruses used to pluralize with "virii" until everyone suddenly realized that made them look stupid instead of smart?

[lasermaster1977]

Either is correct. Buss is more common in the days of yore. (It's also a brand name)

[Greg]

I see am & pm, but not in the context of day & night. Of course, am = Amplitude Modulation. PWM = Pulse Width Modulation. So, am I correct in assuming that pm = Phase Modulation, as the associated image suggests?

Yes, by PM I mean phase modulation, or modulating the quadrature. Entirely a feature of whatever formula one computes points with. Nothing to do with LII. Also the Z here means 3d projection onto a 2d plane, not Z axis rotation.

[Greg]

Steve, that's so sad about your mom. Nothing in life is more valuable than having a great mom. And when they go away one loses a huge part of oneself. Lost mine in 2020.