Forums > MaxMSP

signal to gate or envelope

October 25, 2013 | 1:36 pm

Hi
I have had a nosey around the forum and also through the Max examples, trying to find some pointers on envelope following. If there’s one lurking in the Max folder and I missed it – sorry!

I recall PM answering a similar or related topic here, but cannot find it either, despite searching, so again, apologies for not finding a pre-existent solution, as I know this type of question has appeared numerous times before.

I am trying to generate a simple attack-sustain-release envelope from signal input, that is, a monophonic guitar line, such that I can impose a variable envelope on each new note. You may have seen this on the MFOS youtube channel. I’ve had a stab at it myself, based on the Max simple-compressor example and it’s almost working, but it occasionally misses the onset of new notes very close to the end of a previous one; perhaps you can have a look and suggest a better way:

<code>

– Pasted Max Patch, click to expand. –

</code>

Brendan


October 26, 2013 | 2:40 am

FWIW

I found an envelope follower abstraction lurking in the m4l-patches folder; it seems to centre on the use of [slide~]. I’ll see if I can get this working better than my attempt. Next stage in my "digital subcommander" is a frequency-divider, for a big fat sub-octave and some RM/FM and LFOs.

Brendan


October 26, 2013 | 2:43 am

Wow! Had a poke around the wiki too:

http://cycling74.com/wiki/index.php?title=MSP_Dynamics_Tutorial_1:_Envelope_Following

"does exactly what it says on the tin"


October 26, 2013 | 3:29 pm

I like this one:

Average~ 100 rms
Slide~ 80-200 2000-4000

With gain, conversion to db as needed.

Works great on percussive attacks.


October 26, 2013 | 4:07 pm

Peter, thank you. I did fall foul of the difference in behaviours between [avg~] and [average~]. But [slide~] is pretty much the solution to this question. The [omx.peaklim~] advanced help tab is also invaluable. Tinkering with the slide values is where the craft lies!

Best
Brendan

(if there is any further interest, I’m cooking up a funky recreation of Ray Wilson’s MFOS subcommander in Max . . . )


October 27, 2013 | 8:54 am

Totally, and please consider contributing it to BEAP! There’s a style guide in the misc > Development folder.

BTW, regarding slide: the ms values are not how long it takes you to get there! (even though that’s what the documentation says)

Slide~ is a really efficient object, but the timing is a little trickier. It approaches the value in an asymptotic fashion. Chamberlin published a rule of thumb for it several decades ago; it’s more practical in envelopes where you have a target, but it’s basically: overshoot by 5% (not advisable here), and divide your time value by 3. (it gets something like 61% of the way to the destination in a given time interval)

(You can see this in my AnalogKick device)


October 28, 2013 | 9:16 am

So, I spent an afternoon or two applying new objects, skills etc and have a pre-alpha to share; it’s a short demo of a Max patch for envelope following, auto-filtering and pitch shifting, in the style of the MFOS subcommander guitar synth. I’m placing it here because it’s not a strictly share-ready or project page viable system yet.

todo:

add a VCA-like module;
fix sub/super octave settings;
add a live audio input module.

Feel free to share, like, twoot or whatever it is you kids do on the interweb these days.

Brendan

>n00b_meister; re-inventing wheels whenever unnecessary<


November 2, 2013 | 5:08 pm

Hi
if anyone wishes to see/hear stage 2 of this little project, I have added 2 further modules: a "freeze frame" section and a "drawbar" section. These allow the user to capture and freeze live input, and to blend in 8ves, 4ths and 5ths from the original source; in conjunction with the existing auto-wah and re-pitch modules, one can generate quite rich or dense textures from monophonic input. There are no show-stopping algorithms here, this has merely been a weekend project. And my GUI design is a yawn-fest :( Any tips?

I don’t want to clog up the forum with video again, so you can find it on youtube under "mfos homage" or "brendan mccloskey" if curious.

Bye

Brendan


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