Topics

1

preenfm2 and preenfm3 / Vosim & al.

« on: November 11, 2023, 02:02:21 PM »

Hi,
lately i tried to make some choir patch on the preemfm and quite failed at it
i guess it's not that easy to be done with fm, i had to find something else...

Fortunately, there is great informations on the internet !
https://electro-music.com/nm_classic/015_workshops/Clavia/NordModularWorkshops&Threads/WerkMap/WorkShops/Hordijk1999-2000/VOSIM.html
https://scsynth.org/t/fake-resonance-aka-windowed-sync/2720

so i tried to add new algo with windowed sync oscillators 

here is some quick snippets done with it :
http://sndup.net/tmfx
http://sndup.net/v7wy

Code start here :
https://github.com/pvig/preenfm3/blob/75144a2b58bacd852ae444163dde0cbc9ffc3432/firmware/Src/synth/Voice.cpp#L3621

There is a color code on the preen screen for synced osc.

I chose simple algos : 3 & 4 osc, based on Algo2, Algo 6.

Suggestions and comments welcome about that !

(firmware attached, built on top of 1.02)

2

preenfm2 and preenfm3 / Mixer select from midi

« on: June 06, 2023, 07:39:43 PM »

Hello Xavier,

lately I tried to recall Mixer files from midi,
but found it a bit tricky to do, because of the CC#0 & #32 to set before sending program change.

In my opinion, it would be much easier to use midi bank 127, and program change.
I don't think midi bank 127 is likely to be frequently reach anyway !

for now, I'm a bit lost in the code, i guess it should be done in MidiDecoder.cpp but i have a hard time figuring things out

i would be grateful for some help here

3

preenfm2 and preenfm3 / Fugue Machine

« on: June 05, 2023, 07:36:51 PM »

Today i found this video about the Fugue Machine on iOS :
https://www.youtube.com/watch?v=AZlOquELE_A&t=1s

imagine this on the preenfm3 sequencer 

4

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.

5

preenfm2 and preenfm3 / lfo shapes

« on: November 17, 2022, 10:24:08 PM »

as i found my preenfm lack of drifting, i added 3 new shapes for the lfos, to make it more "analog"

Brownian : lowpass filtered noise, discrete values
Wandering : interpolated noise, continuous values
Flow : lowpass filtered & interpolated noise, continuous values

audio demo : http://sndup.net/m8vs
(only changing the lfo shape, first the 5 known shapes modulate a filter, then the 3 new ones)

https://github.com/Ixox/preenfm3/pull/34

6

preenfm2 and preenfm3 / Reverb dry/wet modification

« on: November 05, 2022, 11:02:00 AM »

Hello,

i'm not totaly satisfied with the way the dry/wet work, sometimes a classic send is just what is needed.

So i propose another way :
- between 0 and 0.5, the dry/wet behave like a send : ie there is no volume loss from the dry signal.
- from 0.5 to 1, the dry fade out, we can hear only reverb signal at 1.

compiled firmware attached if anyone want to test.

@Xavier, i did a PR for that if you want to have a look : it's a very minor code modification.
+ There is also another PR for fixing a nasty bug

7

preenfm2 and preenfm3 / Envelope curve selection

« on: October 23, 2022, 09:47:58 PM »

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)

8

preenfm2 and preenfm3 / [available in v1.08] global fx attempt : REVERB

« on: April 23, 2021, 10:48:58 PM »

hi guys,
i lately did some code in the fx department,
it lead to something i quite like, so i thought i should share it.

First, there is a fx bus on Mix page 3, one can send each timbre to the bus with a send parameter.
Then the bus is send in a "harmonic tremolo" effect, which does soft modulation, hard to explain.
Then it goes in a comb filter, which has an envelope follower and a lfo.
These two filters can be tuned with 2 new Global pages in the Mix section.

it is quite inspired by the mighty fl-201, which do wonderful 3d things to a mix.
https://www.eventideaudio.com/products/legacy/fl-201-instant-flanger

i'm aware that it suffer from aliasing, but right now, the only cure i know for this is oversampling, which would use much more cpu and memory.

So, yes, it is what it is : a crude digital attempt for an instant phlanger, but i found it quite nice if carrefully tuned

for more details, here is the readme :
https://github.com/pvig/preenfm3

find the .bin as attachment : it is build over the 0.107 code.
(edit : found bug, updated .bin)

9

preenfm2 and preenfm3 / compile preenfm3 sources

« on: February 12, 2021, 06:46:12 PM »

Hello Xavier,
i'm trying to figure out how to compile the preenfm3 firmware..
so far, i compiled preenfm3.bin without errors but the debug version is a 65ko file ,34ko for the release one, far from the ~430ko of the latest version.
I don't understand what i'm missing, maybe you can point out my errors please?

the way i did it :

Git clone the project
then in STM32CudeIDE, i create a new STM32 Project from an existing STM32CubeMx configuration .IOC : so here i use preenfm3/firmware/preenfm3.ioc
i press the build button and that's it.

obviously, not the good way.

10

preenfm2 and preenfm3 / dfu mode issue

« on: January 11, 2021, 10:48:34 PM »

hello,
i have been struggling with the preefm3 build for some time, due to a weird issue :
the dfu mode did not set up when i linked BootD and DFU pins : it seems that the DFU pin does not hold any voltage (on naked board, nothing plugged except usb )
Finally, i linked 3,3v with bootD and could then enter DFU mode and flash the firmware.
It start, the screen seems to work ok, but not the sd card (error #6)
And now, the control board does not act as it should : complete mismatch of buttons and actions.
the 5v pin on left of main board has no voltage as well, there may have some sort of short somewhere, but i can't figure out where  :
the soldering inspection did not give any result (joined two photos of the board, with some voltage values.)

surprisingly, I can play notes and even edit the patch with USB!

Any hints is appreciated...

11

preenfm2 and preenfm3 / some food for your preenfm

« on: June 18, 2020, 03:15:28 PM »

lately, Nintorac Audio made something great with AI & the dx7 patch archives floating around in the web !
https://www.thisdx7cartdoesnotexist.com/

12

preenfm2 and preenfm3 / Some new hacks

« on: May 07, 2020, 11:08:19 PM »

hello,
here is a firmware with two new things :

1. modulators envelopes are now loopable
with a small trick : set release to level 1 and duration to zero, the env will loop A,D,S part of the envelope.
you can emulate a delay fx with this trick

2. start point of the two seq is now usable as destination in the matrix (sq1S and sq2S)
a useful use of this :
set a seq tempo to zero and use a linear note scaling as modulation source of the start point, the seq is now 16 keyboard segment !
i use this to make drum kits..

please find the attached firmware and and drumkit patch example.
cheers !

13

preenfm2 and preenfm3 / poly glide

« on: March 23, 2020, 09:36:36 PM »

hi all,
i hope you're all well in this strange times

with this extra isolation, i did play a little more with a poly glide attempt (fw attached)
i think it is now quite playable but need to be played to find bugs and improvements
as a bonus, some filters are back and have been reworked
and then there is 3 new matrix destination :
G.hd : glide hold (if >0)
G.rt : glide rate
G.sk : glide skew (different glide speed for ascending or descending intervals)

(edit: file updated)

14

preenfm2 and preenfm3 / more matrix sources

« on: January 06, 2020, 08:38:42 PM »

hi,
as suggested by @maki, i tried to add some sources in the matrix :

rndK (random on new Key) :
 new random value with each new note

notD (note Difference) :
 difference between current note value and previous one.

velD (velocity Difference) :
 difference between current velocity and previous one.

actv (actives voices) :
% of voices played in current timbre

rpt (repeat) :
at each new note, value increased by by 1/16 if note = previous note, else decrease (min 0, max 1).

dvrg (divergence) :
 value increased by by 1/16 if note different from previous note, else decrease.

that's what i could get with very few code modification and cpu impact.

here is the git commit for those interested :
https://github.com/pvig/preenfm2/commit/fa29cf8748360fbe0865c30cb072e355fef81082

and then the built file if you want to check it out.

15

preenfm2 and preenfm3 / New filters

« on: August 11, 2019, 12:57:50 AM »

hi,
I finally dared to dig the preenfm code, and, it was worth it 
here is a firmware attached, that include some more filters :
- lp2 : lp with double filtering
- same for hp2 and bp2
- tilt : adaptation of this : https://www.musicdsp.org/en/latest/Filters/267-simple-tilt-equalizer.html
- allpass : simple allpass filter, need some more work, not sure what to do with this one...
- saturation : this : https://www.musicdsp.org/en/latest/Effects/42-soft-saturation.html
- sigmoid : a classic tanh distortion : https://www.musicdsp.org/en/latest/Other/178-reasonably-accurate-fastish-tanh-approximation.html

I hope you like it!

your ideas and bug report are welcome.

If you want to see the code, here it is : https://github.com/pvig/preenfm2

(edit 2019-09-11 12:45:37 PM : updated attachement)