Hello! Pandemic Lunetta.

[kanebri]

Hi Everyone,

I'm a LONG TIME lurker, but first time poster. Inspired by so many of the amazing circuits and designs on this forum, I decided to make my first lunetta as a way to keep occupied during the pandemic. I started back in the summer and just installed the final panel last week.

I owe ALOT to all of the collective wisdom here, but a special shout out goes to Phobos. I followed his example of using screws and alligator clips. I also included his brilliant flicker LED oscillators and gated 4093 oscillators. Thank you, Phobos! (Insert worshipful thank you emoji here!)

Most of the modules are pretty straightforward--dividers, mux, multiplier, shift register. But there are two that I'd like to share with the forum, so I can feel like I gave a little something back.

1. The irregulator. I wanted to get more irregularity and randomness out of my synth, so I made a circuit that cranks out unevenly spaced pulses. The heart of it is a transitor configured to produce white noise (by reverse biasing one of its diodes). Then that stream of noise is run through an op-amp comparator to filter it down a bit (connected to the knobs on the front) and a divider, to slow it all down even more and make it more into a pulse stream than just a blast of noise.

It works pretty well, and it is nice when connected to the multiplier circuit. I can toggle the switches on the multipler and to control the overall rate of the irregular pulse stream. It also seems to be affected by the amount of current being used across the whole synth--so sometimes it just goes a little bit weird all by itself. I guess that's a bug but I like to consider it a feature!

2. This one might be cheating, but...I also found that I wanted to be able to trigger a wider variety of pitches to use in things like the Melody Generator and other circuits. So I made a circuit that uses an Arduino nano to drive an old AY38910 (one of those chiptune style sound chips). I can trigger new pitches, or change various ways in which the pitches are made (chromatic, scalar, random, etc.) with CMOS level signals. The AY has three voices available: I'm using two for pitches and one for noise. I also the little mini usb port of the nano right to the front of the lunetta so I can reprogram it as needed, or even send commands from the computer to change modes or whatnot while the lunetta is going crazy.

When the Irregulator is triggering the AY, I've been able to get some really nice melodic figures, chords, rhythms. I'll post some tests/examples if anyone is interested in hearing them.

Anyway. This is really just to say THANK YOU to this amazing forum. I've learned so much here and found so much inspiration.

--Brian

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[wakyct]

Wow those look great, if you have time to post some samples that'd be super. I'm new to the forum and thinking about my own Lunetta project, thanks for the inspiration!

[blue hell]

Cool project! looks good

And Brian.

[dk]

Welcome and nice looking machine!

[PHOBoS]

that looks great! what did you use for the frontpanels ?
I need to look for those panel mount USB connectors, that seems a lot easier to work with than having to
position the arduino behing a large hole. I have been thinking about making a simple module with just an
arduino but I am not sure yet what kind of hardware to add. (switches/LEDS/pots/inputs/outputs)

[kanebri]

Thanks for the comments. I'll try to post a little bit of audio too.

Phobos, for the front panels I used plastic sheets that are intended for laser engraving. I found them on Amazon and figured I'd give them a try. I printed out the panel designs on toner transfer paper, and ran the panels and transfer paper through a laminator to do the actual transfer. It's similar to what you'd do to make your own toner-transfer PCBs. They are stiff enough to work well for the front panels but also easy to drill.

The usb port is, I think, meant for boats or other places where you need a little usb extension. I'll toss in the link below. They come with a super cheap plastic hex nut that broke in about 2 seconds flat. They also have a weird cap that you can use to protect the usb port when not it use. I ended up drilling the top off that cap and using it to mount the whole thing. Worked out all right...

But I gotta say, I like having the arduino accessible and being able to reprogram it on the fly.

Here are the links on Amazon to the stuff mentioned above:

https://www.amazon.com/gp/product/B07HQSKMN4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B082J1BL6H/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

[NOISEBOB]

wow.. what a pretty little thing!!!

[kanebri]

I finally got around to uploading some audio samples of the Lunetta.

In #1 you can hear the irregulator cranking out some irregularly spaced pulses and triggering pitches on the arduino/AY38910.

In #2 there's some heterophony generated from two voices on the AY38910 driving the classic melody generator patch.

In #3 I'm playing with switching between different pulse streams on the irregulator to generate some melodies. I'm also switching between various "modes" for choosing pitches on the AY38910 (chromatic, diatonic, random, etc.)

#4 has lots of fast, chromatic, Lunetta insanity.

It's been super fun to work with it. Long live Lunettas!

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[L´Andratté]

Kanebri very nice work and nice play!
#1 and #4 have (tiny) musical rests what makes the sound extra interesting!

[Ruebezahl]

That's really good looking and sounding machine! Inspiring!

Also i never really came across the 4089! multiplier sounds intriguing, although it actually seems to be rather a Divider, kind of like logic controlled 4040, in spite of a better description. Although where the 4040 puts out frequencies only divided by halfs, this chip can also do odd divisions. Although if i look at the logic table, it seems rather than even divided waves, it looks like the output wave omits certain steps, so if for example at the inputs we have 1101, and the clock is let's say 16 steps per second, then we would not get a wave with 13 even pulses, but rather a wave with 16 steps, and three of them are just missing, right? So for getting pitches it's probably not that great? Rather for cool rythmic divisions. kind of like an euclidean sequencer, when i think of it!

Sorry just getting excited and hijacking this thread talking to myself Feel free to explain what you usually use this chip for, though, i am eager to learn more

[kanebri]

Ruebezahl, you're absolutely right, the 4089 works just the way you described it. It's not great for getting pitches, for the reasons you mentioned. I use it as a way to filter a stream of faster pulses. If I take the output of from the Irregulator, I can feed it into the 4089, and by selecting different bites get different degrees of density (pulses per second, etc.). I can thin out a dense stream of pulse by only allowing 1 pulse per 16 out, and so forth. Also, because the irregulator makes an irregular pulse stream, the 4089 tends to keep that irregularity audible, so the streams aren't totally predictable.

I put switches and bolts on each of the bits, so I can either manually control it (set it for, say, 1101, or whatever) or just hook it up to oscillators or counters and let the Lunetta set it. If I hook the most significant bit to a really slow pulse, say from a divider, you can get big shifts in texture. If I feed the output of the 4089 into the clock of that divider, and then let the divider select the inputs, you can get some really crazy results.

In general, I like having ways of controlling overall density and other global level phenomena with the Lunetta. It's one of those lessons learned from reading Xenakis' writings: work with chaos at a global level and let the details take care of themselves.

I'll try to post some audio of the 4089 in action so you can hear what it does.

[Ruebezahl]

Thanks for the explanation, sounds quite cool! I will definitely start playing around with this chip too!

Also curious for any recordings!

ah, btw. how do you power this whole thing? Just a regular DC wallwart? 9V? And is it meant to be modular in a way that you could swap modules? e.g. the power supply to each module is with clips and you only need to unscrew the modules. Or everzthing is soldered together? I am also thinking about making kind of a Lunetta Modular, and let it slowly grow, just still thinking about these basic design questions. Do you have any pics from inside?

[Steveg]

With a slow clock speed the 4089 can give you rhythm patterns by itself.
For tone division start with a much higher oscillator rate (say x16 or x32) run it through the 4089 and then run that through a 4040 or similar to get a less jittery output. Note that you can cascade 4089s to give higher precision divisions. Unfortunately they are a bit hard to get now but they were the mainstay of clock projects in the 80's.

[kanebri]

Ruebezahl,

Thanks for keeping the thread going! It's fun to share all this stuff...

Re: power and modules. The whole thing is powered from a 12V wall wart. It could run at 9V or other values. The RCA plugs in the back are actually being used for power. (It's what I had around!) You swap modules in and out by unscrewing them from the front and plugging them into the stack of RCA jacks. It is a huge rat's nest back there!

The mixer module also has the power supply, filter caps, etc., and you can plug the wall wart in through the front panel. That's the one module that isn't swappable.

Re: 4089. I've recorded some samples of how I like to work with it. A lot of these aren't much to listen to but they might be illuminating.

1. Irregulator Solo. The first one is just my "irregulator" module kicking out a stream of irregularly spaced pulses.

2. Irregulator to 4089. I'm clocking the 4089 with the irregulator, and then changing the divisions. You can hear the overall rate of the irregular pulses go from slow to fast as I change the divisions.

3.Irregulator to 4089 to Arduino. Now I'm taking the 4089 output and triggering pitches from the built in arduino/AY38910 sound chip. Now we're getting somewhere!

More soon in another post...

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[kanebri]

Ruebezahl,

On the topic of the 4089 and modularity, I swapped in another module recently.

I wanted something that would drive the 4 bits on the 4089, so I came up with this weird thing. One half of it is a phase locked loop, for getting laser sounds and whatnot. The other is three flip flops with some mods. They can all be synced to a single clock, and they have the option of getting their data from a flicker LED (inspired by Phobos, and his flicker LED oscillators). The idea was for each flip flop to have a source of random data, so that I could generate random binary words. I've only got three flip flops going so it can only make 3 bit words out of it, but I use those to drive the 4089 and get different subdivisions of a pulse.

There's probably a clearer way to say that...need more coffee...

Pictures and sounds are worth a thousand words so here goes...

1. A sample of random words going to the 4089.
2. That same configuration now triggering both voices on the Arduino/AY38910 sound chip module.

Cheers!

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[kanebri]

[Ruebezahl]

Thanks a bunch for the detailed information and the sound samples, didn't expect so much so quick! Your delivery is quicker than amazon prime

Cool idea with the RCA-distribution. Oh so you screw those panels right on the wood, i thought some metal rail would be necessary. Won't the screwholes get loose when swapping the modules too often?

Is your mixer also lunetta style, or did you go for op amps there?

And i am super curious about those flicker LED oscillators, but i couldn't find anything through the search. Is there a thread or something where phobos is explaining how those work?

[kanebri]

Quicker than Amazon Prime, but less evil!

Here's the link to Phobos's awesome lunetta. The flicker LED oscillators are described on the first page (I think). Anyway, the whole thread is a treasure trove. (Thank you Phobos)



https://electro-music.com/forum/topic-55465.html

I ended up buying a few different brands of flicker-LEDs and auditioned them. I found some recently that make different patterns from the ones I currently have installed, so I need to do some desoldering...

The mixer uses op-amps. It's similar (again) to Phobos' mixer, on the same thread as above.

I am screwing the modules right into the wood. So far its been okay swapping out panels, but I don't do it all that often. I probably should have installed some rails. I can always retrofit a new case, I suppose, and do it right. Hmmm.

[PHOBoS]

[kanebri]

Inspired by the comments on this thread, I've been playing around with the 4089, feeding it clock pulses in different ways, while also sending it random binary words (from the flicker led -> flip flop unit described above).

I've been especially enjoying sending it really slow pulses. For instance, I've been sending another flicker LED into a 4040 divider, and using the slowest pulses as the source clock for the 4089. What I like about it is that I'm able to get some really slow, really irregular, pulses that can trigger events or change states.

Here's an example. I grabbed about 5 minutes raw audio, letting the lunetta run, popping out little sound events punctuated by silences. Then I went back and overdubbed another take to get a little duet. No other editing. The tracks are hard panned left and right. I'm digging the weird "dialog" that emerges, and like the mix of silence, long held tones, and weirdness--with a bit of a serial music aesthetic.

So, thanks for the 4089 questions and comments!

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[PHOBoS]

nice one
love the glitchyness!