paraphonic effects

[Toltekradiation]

Still a work in progress...
I attached on the first post of this thread a new fw version, with 2 more fx :
- ping pong delay : very short one, but may be of some use
- Karplus Strong : 2 plucked voices on top of the instrument
 

[ElVicente]

Hi toltekradiation.

I did a quick test with the fx and they are really a great addition to the machine imo. Choruses and flanger are great once modulated with an lfo, but it obviously would be quicker that lfo was included already in the fx.
The widener sounds definitely great to my ears, I like less the harmoniser. I'll do more testing...

Did I read correctly that you could add some oversampling filter. Would that mean that it could lower the aliasing of the synth ? That would be awesome !

[Toltekradiation]

Hi ElVicente,

yes, oversampling is definitively doable, but i'm sure it would be so useful :
it would be good to make a very clean filter, but the aliasing already there is not easily removable.
however, i have to do some tests.

I agree about the harmonizer : as it does not use the scala tuning and not even regular tuning, it's difficult to have a usefull result, works best on drums  . I will try to change that.
I did tuned delay line with the pluck algorithm, it may be usable in the harmonizer.

About the chorus and flanger, i agree it is not ideal, but i'm not sure how to do it : one may like using multiple lfo and other modulation source.

[ElVicente]

Ah so the aliasing would have to be taken off at Oscillators levels I guess, (sorry I know very little about dsp!)
The aliasing in the filter don't bother me as much as the oscillator ones, especially when sliding those high notes...
So I was hoping it could got better with thoses oversampling ideas... 
Anyway, thanks for your work on these effects, they already open quite a bit new sonic possibillities!
Looking forward to what it becomes.

[Toltekradiation]

I wish there were a way to cure aliasing but i fear we must live with it.
The usual way to lower aliasing is by using the note scaling in the modulation matrix, with modulation index as destination.
For example, full modulation at C4 up to pure sine at C8 (only the carrier left, no more modulation).

[Toltekradiation]

Hi,
after some bugfix & enhancements, here is a quite mature version of these fx.
I removed the karplus strong fx, it was not so useful as an effect. Instead, there is a diffuser, to blur transients or add a light reverb "touch" to the sound.
There was improvements in some fx : the pitch shiters were simplified to lower cpu usage, it allowed to add some Eq ing in these to retrieve the lost bass, same for Bode filter.

@Xavier : pull request done in github.

[matrix12x]

@Toltekradiation thanks for the great work!! I'll probably install the update tomorrow. Did you add menu options for the new FX yet? or do we still use them via MIDI CC?

[Toltekradiation]

yes, the menu option is unlocked, no need for CC access.

[Xavier]

Oh nice that's a PR against the rebased version

I'll seriously have a look at this after the vacations in 10 days i think.
Thanks a lot !

[superfake]

Hi Toltekradiation!
Thank you so much for the excellent work done!
I noticed that some delay effects (Delc, Ping, Diff) have a high -frequency whistle around 12 kHz, regardless of feedback, which complicates their use somewhat. Attached the screen.
The rest is wonderful effects. ))

Do you plan the effects of delay with longer time values, if possible?

[Toltekradiation]

Hi superfake,

The delay fx could be done with a sample rate reduction trick, which is x4 factor, so yes, the 12khz noise is awaited..
I did put some lowpass to soften this, but it's far from perfect, let's say it's a feature and call it vintage delay ^^
Though i will try some notch filtering to minimize the noise.

about the delay length, there is not so much ram left... better keep it for other features.

[Toltekradiation]

Hello @superfake,
thank you for your detailled report, i previously did not use spectrum analysers, only my ears, which has now some hf loss i fear.
So here is a version with more lp + notch filtering around 12khz on those fx, i hope it will make it usable, though it remains some aliasing.
Please, let me know if that's ok for you.

While i was at it, i added an optimisation i found lately on all the pitch shifter fx, which save quite some precious cycles !

[superfake]

Hello @toltekradiation
Wow! This is incredible! Now it works perfect for me. ))
Thank you for these effects now Preenfm3 has become much more self-sufficient. ))

[Xavier]

Any git commit i can cherry pick ? 
I really have to merge that in master i know
The biggest work is done with the last rebase. I'll do that in the coming days.

[Toltekradiation]

Sure, here is the commit :
https://github.com/pvig/preenfm3/commit/dbab9d26872e675900df2eb76705185d585e0cde