Messages

91

preenfm2 and preenfm3 / Re: paraphonic effects

« on: April 23, 2023, 05:20:55 PM »

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.

92

preenfm2 and preenfm3 / Re: FM3 MIDI CC list?

« on: April 18, 2023, 11:03:58 PM »

there is also CC_MIXER_SEND ( CC#11 ) for reverb dry/web, for each timbre

93

preenfm2 and preenfm3 / Re: Envelope curve selection

« on: April 15, 2023, 08:56:50 PM »

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 !

94

preenfm2 and preenfm3 / Re: Envelope curve selection

« on: April 03, 2023, 06:52:17 PM »

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 !

95

preenfm2 and preenfm3 / Re: paraphonic effects

« on: March 09, 2023, 09:37:35 PM »

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).

96

preenfm2 and preenfm3 / Re: paraphonic effects

« on: March 06, 2023, 08:07:00 AM »

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.

97

preenfm2 and preenfm3 / Re: paraphonic effects

« on: March 04, 2023, 11:55:53 AM »

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
 

98

preenfm2 and preenfm3 / Re: paraphonic effects

« on: February 26, 2023, 11:42:55 AM »

Hi Xavier,

these fx can be found in the FILTER_TYPE list, so on the Filter page. (after unlocking access with CC70 = 54 for example)
the code is in Timbre.cpp, is starts here :
https://github.com/pvig/preenfm3/blob/532fcac3ccb117e609c812c4b0ef09173416787e/firmware/Src/synth/Timbre.cpp#L759

the bigger cpu impact is up to 5.6 % for the Harmonizer and the Widener algo (both are double pitch shifters),
the least is for the delay which is like 2%.

Attached file is  a fw iteration of this :
- delay has now some highpass in the feedback path (more feedback, more hp)
- the Bode fx sounds more like it should on pure sine (bug fix). It's also a bit less harsh when feedback : did put some lowpass in there.

About the Bode fx, the frequency shift may be up or down : for values above or below 0.5
Same behaviour for the pitch shifting algo : The pitch is one octave below for value 0.25, one octave above for val = 1.

99

preenfm2 and preenfm3 / Re: paraphonic effects

« on: February 24, 2023, 09:25:09 PM »

hi Cluso,
thanks for the appreciation !

100

preenfm2 and preenfm3 / Re: paraphonic effects

« on: February 21, 2023, 07:26:37 AM »

hmm, yes it may be the way to do it, i will try it.
Anyway, the cutting should be very low, like cutting below 100Hz or so.

101

preenfm2 and preenfm3 / Re: paraphonic effects

« on: February 20, 2023, 10:50:52 PM »

Great !
i'm finetuning the delay : lower frequencies tend to saturate too much when feedback dialed up, need some highpass.

102

preenfm2 and preenfm3 / Re: paraphonic effects

« on: February 20, 2023, 08:29:43 PM »

uh, sorry for that, i hope it works now as expected  !

103

preenfm2 and preenfm3 / Re: paraphonic effects

« on: February 19, 2023, 01:54:25 PM »

better audio demo for the chorus (slightly ):
http://sndup.net/ndbp

triphase chorus then dim chorus.

For the triphase chorus, it work best with a double lfo modulation, as on the solina chorus : one slow (freq 1~2), one faster (freq 4~6)

There is room for improvements, please let me know if you have any comment about it.

104

preenfm2 and preenfm3 / Re: paraphonic effects

« on: February 19, 2023, 09:57:05 AM »

Something worth noting : as the new effects are outside the current effect list, those can be reached only with external CC 70.

105

preenfm2 and preenfm3 / paraphonic effects

« on: February 18, 2023, 01:06:45 PM »

hi,
lately i did some research about the opportunity to add some fx to the pfm3,
the goal was to add some time domain fx in the timbre layer, instead of in the voices, to save cpu and allow some ram to be used.

So, with 2kb per timbre, interesting things can be done, like flangers, chorus, pitch shifter, frequency shifter...,
Even a delay can be done by dividing the sample rate by 4 : this give a 170ms lofi delay which may be quite usable with enough lowpass.

A small trick had to be done to do all of this, one must calculate the modulation matrix of the last played note, even after the note ended :
https://github.com/pvig/preenfm3/blob/fe19cdc612f00cf5129821376742faefc2a53d3f/firmware/Src/synth/Timbre.cpp#L775

Something different from the existing filters is the behaviour of the filter gain param : with these new effects, it work like a dry / wet, which is better suited for this kind of effects.

Some raw audio snippets :

flanger, various kind of chorus, then the double pitch shifter fx (like on the eventide h3000) :
http://sndup.net/g5mj

frequency shifter, then the crunchy delay, then the pitch shifter :
http://sndup.net/wqhj

Current effect list is :
Flanger, triphase chorus, dim d chorus, pitch shifter, harmonizer (double pitch shifter for large intervals), frequency shifter, widener (double pitch shifter suited for small intervals), lofi delay.


Further effects may be done, like oversampled filters, but for now i'm happy with this set 

Edit :
I forgot to add the fact that i found a memory optimisation in the reverb section : by halving the sample rate of the predelay, 8 kb of ram can be saved.
It's barely noticable as the reverb input diffuser wash a bit that part of the signal anyway.

(fw bin attached)

Edit 2 :
i talked about kilobyte above, when i should have say kilo-float which is 4 time more kilo bytes.