Ableton AAS Analog Synth Filter Envelope

Analog is a good synth, I use it a lot. I pulled out several killer sounds from this little beast (and a couple of effects). Analog filters are nicely aggressive and the management of filters' envelopes is very powerful. 
Although generally I love to program sounds by ear, under some circumstances it's good to know more 'scientifically' what the fuck is going on.
For me one of the greatest mysteries of the twenty-first century was: why the hell the filter envelope range in Analog is (-16,  +16)? 

Analog Filter Env Parameter. (-16, +16) range.
Ok, a 16-based value opens the filter relative to the starting point, set with the Freq control up there, and if you input a negative value the filter Q will swing in the opposite direction (nice stuff). But what does -16 and 16 mean in terms of frequency in Hz? Analog manual is pretty useless in this regard.
Until some time ago I stumbled across this great article by Andrew Mylko. Really worth reading: there are mentioned many important concepts the author has studied/discovered trying to make Welsh's Synthesizer Cookbook patches with Analog. But that's another story.
In short, the Env values represent the multiplier of the starting frequency, in exponential flavor, through which the end (frequency point) of the filter Q swing is calculated. Look here (click to enlarge):

So, if I want the filter to start at 50Hz, and open up to 3.2kHz, I have to calculate the right multiplier, the ratio between 3200/50 = 64. Then applying the above chart put a good 6 in the Env field. Below a lin-log graph with all possible values.

x linear, y logarithmic
Seems difficult, and indeed it is! However, to facilitate the task of doing the calculations, I created a maxforlive midi device with the worst name ever: AnalogFiltEnvCalc.
Use 'Q to Env' if you want to calculate the correct Env value, also useful to copy some patch from other synths to Analog. Use 'Env to Q' if you want to calculate the frequency end point (Q End), also useful to copy some Analog patch to other synths.
Watch this short video and you'll understand everything [No audio. Just look at the spectrum with filter Q perfectly swinging to 10k with Env set @7.97]:

A side note. The funniest part was rediscovering this logarithm property: loga(x) = (logb(x)/logb(a)) where the emphasised letters represent the base of the logarithm. Prof mi sei venuto in mente.


  1. Great job and great article. I still disagree with Analog being good though.

  2. Thanks. Ok, it's not U-He Diva but is good enough for me in most situations, and has a practical interface. :-)