Envelope curve selection

[Toltekradiation]

Hello fellow preenfm lovers,

after hearing in various places on the internet about virtues of envelope curve selection, as done in many vst and synth, i tried something for the preenfm 3 :

i added a new page for the Oper/Env menu entry. From there, one can select the curve style of any stages of the envelopes.
While i was at it, i added some custom envelope curves (screenshot attached), so selection options are Exp / Lin / Log / Usr1 / Usr2 / Usr3 / Usr4.

The curve change is usualy quite subtile, but there is some use cases:
Exp shape on short attack is a little bit punchier than linear.
Log shape on attack may be good for woodwind instruments. It may also be useful on release part, to add more sustain to the sound.
Some of the custom curves sounds quite noisy on short envelopes, which may be used for adding noise burst on the attack, for example.

Please, let me know if this sounds useful for you or not so, or if all of this is complete nonsense .

(latest firmware, modified, attached below)

[ericd]

This does sound useful! Having these envelope options is a great idea, especially for extra clicky-ness on percussion sounds; thanks!

[Toltekradiation]

Thanks for the appreciation !
This keep me going on : next step is to handle the user curves the same way oscillators shapes are : with user files.
Then a puredata patch to generate the files and we're good to go for experiment

[Xavier]

Nice mod !!! 
That's interesting
I'll give a try to see/hear how the Exp/Lin/Log makes a sound difference on the attack.

[Toltekradiation]

Some progress on that project :
i now have a version which load user envelopes files from sd card,
it does not allow saving ; it needs a lot of testing before that anyway !

joined are four curve files to be stored in pfm3/envcurve
(some of those have extra clickyness)
But if you want more, the puredata patch is here for generating new usr files.

Code is on that branch : https://github.com/pvig/preenfm3/tree/env-curve

[Toltekradiation]

Sorry for anyone who did a test to that firmware : it did not work properly (it worked only once after installing )
The previous post is now updated with a working version.

That's what happen when you post a firmware and then go away on vacation without much testing !

[Toltekradiation]

ok, it seems i'm done with that feature : here is a firmware which can save and load patch with envelope curve selection (Works with mixer and patches)
It's not a game changer feature, but i like it for what it is , and i think it's quite versatile with the user's curves

@Xavier, here is another PR, containing 2 of the previous ones (bugfix + reverb send mod)
https://github.com/Ixox/preenfm3/pull/33

(firmware below)

[Xavier]

Thanks a lot.
I'll take a look at the code before merging.
The fact it's in a "second env" menu makes it interesting as it does not make anything different untill you want to change the env shape.
 

[matrix12x]

This is a great idea. I also like the idea of the second env menu.

[Xavier]

I'll hopefully have some time at the end of the month to look at that. 

[truth teller]

this is DEFINITELY a game changer!  where do you get the idea its not?

will this be added to the aux envelopes?  to be able to modulate stuff in the matrix would be way more of a game changer.

[Toltekradiation]

I reckon it would be nice to add this feature to the aux env,
but these envelopes do not works the same way as the osc ones, and it's not an easy task to adapt the code

Maybe one day, but don't hold your breath !

[truth teller]

its not as much of a game changer as it could be then.  im very glad to have it but to route it to many destinations would be the game changer.  thanks for the awesome work!

is the lfo able to be a one shot?  that could be a way to get interesting envelope in the matrix, since there are user shapes now.

[Toltekradiation]

no, there is no one cycle mode for lfos, but its worth saying that you can do cool things with the matrix : the mtx1-4 destination let you modulate the level of anything in the matrix slot 1 to 4,
so a lfo can last a few cycles when modulated by an envelope for example.
The preenfm matrix is already quite powerful !

[truth teller]

no doubt!  im a big fan.  ill try that out.

you seem to be responsible for a ton of good features!  you have extended the application of this synth design way beyond its original state.  please keep going!  im not sure if a comb filter would fit if you can think of a way, maybe as a filter?  how about a phase inverter filter?  how about a clipper filter?  how about another filter section in place of reverb, like you would be able to choose, reverb or 2nd filter...  i understand if thats not possible as i have no idea what is

i would say that if you are distorting the output from the synth engine, curved envelopes make it possible to get very interesting results.  they also make it good for percussive sounds in the case of a logarithmic envelope shape.  the value of these envelopes will become clear the more you use them i think.