Author Topic: Feature Request. Increased LFO speed up to 100Hz  (Read 5361 times)

pereshaped

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Feature Request. Increased LFO speed up to 100Hz
« 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


lokki

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Re: Feature Request. Increased LFO speed up to 100Hz
« Reply #1 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...

Xavier

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Re: Feature Request. Increased LFO speed up to 100Hz
« Reply #2 on: August 29, 2016, 10:02:00 PM »
I'd be happy to demonstrate.

I'd be happy to hear :)

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

lokki

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Re: Feature Request. Increased LFO speed up to 100Hz
« Reply #3 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
« Last Edit: August 30, 2016, 03:33:49 PM by lokki »

solipsvs

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Re: Feature Request. Increased LFO speed up to 100Hz
« Reply #4 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

Xavier

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Re: Feature Request. Increased LFO speed up to 100Hz
« Reply #5 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.




lokki

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Re: Feature Request. Increased LFO speed up to 100Hz
« Reply #6 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

« Last Edit: August 30, 2016, 10:09:41 PM by Xavier »

Xavier

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Re: Feature Request. Increased LFO speed up to 100Hz
« Reply #7 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.

lokki

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Re: Feature Request. Increased LFO speed up to 100Hz
« Reply #8 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...