Author Topic: LFO frequency >100Hz. Greater timbral possibilities.  (Read 3935 times)

pereshaped

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LFO frequency >100Hz. Greater timbral possibilities.
« on: November 01, 2015, 03:19:11 PM »
Hello I was just reading the manual and wondered how hard would it be to increase the LFO frequency to >100Hz. Is there a way for users to modify the firmware in order to mod this? This would allow for timbres such as those created on the classic 4 operator FM synths such as the FB01. It afford the possibility of creating a "noise halo" around the operators and gives textures which range from reverberation, authentic wood sounds. This is something the DX could not do.

I can send a demo of the types of sounds this mod would afford users.

all the best, P

Xavier

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Re: LFO frequency >100Hz. Greater timbral possibilities.
« Reply #1 on: November 02, 2015, 09:47:30 AM »
I never tried that.
If you manage to compile the firmware (which is very easy) you can try modifying lin 290 here :
https://github.com/Ixox/preenFM2/blob/master/src/synth/SynthState.cpp
Current values define : min 0.0Hz, max 24.9Hz, number of values 250.

You have to keep in mind that LFO are calculated every 32 audio samples.
So the LFOs refresh at around  1200Hz.
Don't expect to have nice LFO waveform when you increase its frequency.
But that maybe worth giving a try.

Xavier
« Last Edit: November 02, 2015, 09:49:20 AM by Xavier »

SirPrimalform

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Re: LFO frequency >100Hz. Greater timbral possibilities.
« Reply #2 on: November 02, 2015, 03:33:14 PM »
Ahh, so with the low LFO sample rate you'll quickly get aliasing with audio rate modulation of geometric waveforms. Sine LFO should be ok though?

Xavier

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Re: LFO frequency >100Hz. Greater timbral possibilities.
« Reply #3 on: November 23, 2015, 09:34:14 AM »

The problem is that i hacked frequency 24.5 => 24.9 and change them in to midi clock synced frequency.
So that makes the change more complicated if i want to keep the compatibility.

Compiling the firmware is really easy... perfect small project for people who don't care about compatibility with previous patch they have that have LFO synced to midi clock.