Saturday, July 28, 2018

Getting swing/shuffle from a Maths (alone)

My friend/colleague Ben Casey asked a question on Facebook about getting a little swing out of his Maths. At first, I thought that it would need some external switching and stuff, then I realized that it could all be done internal to one Maths.

We will be doing a little wiring:

We'll be using both envelopes of the Maths to pull this off, with the EOC output of the channel 4 (the second envelope) providing the swinging clock source we need. Here's the walk-through (starting off un-wired):

1. Turn on the Cycle mode of channel 4 to ON (cycling), and use the EOC output to trigger something that you can hear.

2. Set the Rise time of channel 4 to zero, and use the fall time to set the interval for your trigger output. Find something that ticks along at a speed that you like.

3. Turn off the Cycle mode of channel 1 (if it happened to be on...).

4. Take the unity output of the channel 4 envelope and run it to the trigger input of channel 1. Channel 1 should now be ticking along in parallel with channel 4.

4. Set channel 1's fall time to zero, and set the rise time to be longer than one of the channel 4 cycles. You should see the channel 1 output LED blinking at half the rate of channel 4 (i.e., every other cycle).

5. Patch the channel 1's EOR output into the channel 4 fall CV input. You shouldn't hear much difference.

6. Now slowly bring up the channel 1 fall time control until you start hearing some swing. You might need to play around with channel 1's rise time to get things just right - but if you've got it together, you should here it start loping along...

Here you can hear me go from straight time, to swung time - to something even odder...

How does this work? We are using the fact that a Maths won't recycle during the rise period to act as a clock divider, so we treat every other cycle differently. We then take advantage of the pulse-wave-like output of the EOR output of channel one to make one of the clock ticks have a long fall time, and the other have a shorter fall time. With a little tweaking, it can give us all kinds of different timing functions (for example, in the audio above, I start extending the channel 1 rise time until it is dividing the clock by 3, 4 and more - then tweaking the channel 1 fall time until I get something interesting).

Hope you find this useful!


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