Melody Generator PlusPlus

[hexagon5un]

Hi all!

I was playing around with the 4015 dual 4-stage shift register chip last night (thanks for the tipoff to the part, Synaesthesia) and was thinking "what do I drive with this thing?"

I know that a bunch of folks use shift regs as taps for feeding 4051 switches, so I hooked up a slacker/voks style melody generator fed by three taps off of one of the shift registers.

But I still had another register sitting there unused. That won't do!

So after playing around with dual melody generators (fun, btw) I thought, "what happens if we divide-down the melody generator output again to get octaves with a 4040?" Select which tap off the 4040 gets fed through to the speaker with another 4051, running off the second half of the 4015.

The two different tempos, resulting from the different shift-register clocks, give it this crazy syncopated feel. I used one single osc for the data input to both registers, but of course you can use one for each.

Doubt this could be original, but it was cool enough that I shot some quick video (youtube) just to save it for posterity before I pull out the wires from the breadboard.

What I really like about this circuit is a ton of complexity from just one audio input source. (And three tempo-rate oscillators.) But not so much complexity that it loses the harmonic-ness. I certainly feel like the short length of the 4015's registers fit just perfectly.

TLDR: 4017 divides down an oscillator to make a pitch, 4040 divides it down again to make octaves, 4051s all around modulate these, and they're run off of a pair of non-synchronized shift registers (4015).

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[synaesthesia]

Finally, the video is up... This circuit definitely was worth saving for posterity. I like the syncopation and the use of a octave divider. A bit chaotic, but still musical indeed.

[hexagon5un]

I couldn't leave the circuit alone last night. I added in a bass drum voice, again triggered off of a tap on the 4015 shift register.

Quick late-night youtubery.

I really like the way the phasing between the clock and data oscillators makes it hit once sometimes and then twice other times in an almost-syncopated rhythm.

I'm going to pull the plugs on this beastie soon, but it feels like a crime.

Shift-register driven drum machines are definitely up next on my list.

It's crazy to compare this circuit with Synaesthesia's Chip Tune Music Box circuits because they use essentially the same chips, just in a different configuration, and get totally different results.

Where the switches in this circuit run at tempo rate and just control the rhythm / melody, Syn's run at audio rate and control the timbre as well as pitch. Makes me think about combining the two approaches...