Patch Tips #1 - Maths Slope Control

First in a new series of tips and tricks, recapping some of the ideas I've covered in Patch of the Day.

It should be fairly obvious by now that I'm an envelope junkie. Of the eight different EGs I have or have had in my system, one of my favourites remains Doepfer's A-143-1 for its natural, rounded 'sound'. It's not the fastest transient generator in my rack, but it twangs a low pass gate like no other. Part of the reason for this is its logarithmic rise and exponential fall:



The only problem with the A-143-1 is that it's large, lacks voltage control and, to be honest, I rarely gang its four envelopes to form one complex CV. I'm running out of space so I wanted to see if I could get the same response out of Make Noise's Maths which, on the surface only offers control over the contour of both rise and fall simultaneously:



With some creative patching, however, it is possible to gain independent control of Maths rise and fall curves, without the need for other modules. Much like the Bananalogue/ Serge VCS, all that's called for is a little feedback:

Set Maths' response knob to linear/ noon. Take two mults of the envelope output and patch one to Maths' channel 2, the other to channel 3. Set channel 2's output to about two o'clock (+) and patch it to the rise CV-in, set channel 3 to ca. ten o'clock (-) and patch to the fall CV. This will give you a logarithmic rise and exponential fall:



Increasing the amount of positive or negative feedback will increase the severity of the response, flipping the polarity to the CV-ins will yield an exponential rise and logarithmic fall. If you want to go really mad, use Doepfer's A-133 Dual Polarizer instead of Maths' 'attenuverters' to gain voltage control over these parameters.