preenfm Forum

PreenFM => preenfm2 and preenfm3 => Topic started by: pereshaped on August 29, 2016, 12:44:59 AM

Title: Feature Request. Increased LFO speed up to 100Hz
Post by: pereshaped on August 29, 2016, 12:44:59 AM

This is a firmware update request.

At 100+ Hz a random LFO wave permits a radically different type of FM synthesis not possible using the DX7 standard LFO. You can sculpt "sample like" realistic materials not possible otherwise.

It would allow the porting of a greater variety of timbres from the 4 operator series using DX Convert, the fabulous app by Martin Tarenskeen of the DX YAhoo groups.

I'd be happy to demonstrate.

all the best, P

Title: Re: Feature Request. Increased LFO speed up to 100Hz
Post by: lokki on August 29, 2016, 09:07:00 PM

i compiled a firmware with increades lfo speed, will try tomorrow if it works as expected and will then upload here...

Title: Re: Feature Request. Increased LFO speed up to 100Hz
Post by: Xavier on August 29, 2016, 10:02:00 PM

Quote from: pereshaped on August 29, 2016, 12:44:59 AM

I'd be happy to demonstrate.

I'd be happy to hear :)

Quote from: lokki on August 29, 2016, 09:07:00 PM

i compiled a firmware with increades lfo speed, will try tomorrow if it works as expected and will then upload here...

Don't hesitate to share  :D

Title: Re: Feature Request. Increased LFO speed up to 100Hz
Post by: lokki on August 30, 2016, 03:00:33 PM

ok, the firmware i compiled (with line 290 adjusted) does crash, i think it is because every time i go past 24.9 there is no access to frequency anymore. first midi, then the preenfm crashes (all leds on, display shows some numbers, unit freezes). so i think i first need to remap the midi-clock mapping from 24.5 to something like 120... xavier any hints, where the mapping takes place?

cheers

Title: Re: Feature Request. Increased LFO speed up to 100Hz
Post by: solipsvs on August 30, 2016, 05:16:18 PM

i was under the impression that xavier said previously that the cpu is maxed out and theres no possibility to make an LFO that speed

Title: Re: Feature Request. Increased LFO speed up to 100Hz
Post by: Xavier on August 30, 2016, 07:03:23 PM

100Hz is not a problem, it does not add any CPU overhead.
The LFO is updated every 32 samples. 100 Hz would make it updated 12 times per period.

A quick hack would be to modify LfoOsc.cpp line 167.
currentFreq = lfo->freq + this->matrix->getDestination(destination);

Change it to :
currentFreq = lfo->freq * 4.0f + this->matrix->getDestination(destination);
And you'll have the LFO frequencies 4 times the number you see on your display.

Title: Re: Feature Request. Increased LFO speed up to 100Hz
Post by: lokki on August 30, 2016, 09:10:57 PM

ok, i went for 5.0f just to be sure  8) , also i adjusted the stepsize of the display, to still get some slow values. it looks funny above 24, but it is not crashing  ;D

this basically just multiplies the lfo frequency by 5, so frequency of 10 is 50 frequency of 20 100 and so on...

since this is a beta firmware, there are also other changes in it, namely pitchbend works as expected and there is a fix for very fast low notes that triggered stuck notes (all fixes by xavier)

@pereshaped: can you try the attached firmware and let me know, if you can get the sounds that you imagine from it? what do you apply the lfo to? im?

cheers

Title: Re: Feature Request. Increased LFO speed up to 100Hz
Post by: Xavier on August 30, 2016, 10:11:36 PM

I changed the name of your firwmare so that there is no confusion with current beta.

If you change the number of steps, there's a chance the "midi sync" ratio freq does not work anymore.

Title: Re: Feature Request. Increased LFO speed up to 100Hz
Post by: lokki on August 30, 2016, 11:24:38 PM

here is 2.05b4 with increased lfo speed... i changed the number of steps back to 250, just in case...