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Adrian B · Post by **Adrian B** » Sat Aug 02, 2014 12:02 am

DIVA : LFO becomes chaotic at high rate of negative self-modulation

An interesting behaviour. It could be a bug or a fun tool to exploit, depending on your point of view. Here's a patch https://s3.amazonaws.com/kvr/Chaotic+LFO.h2p.

Edit: hold down a single note for a long time and hear the irregular rhythm.

Adrian B · Post by **Adrian B** » Thu Aug 07, 2014 9:58 pm

In case nobody else has the same thing, here's an audio file, in this I'm only holding down one note and then change the "rate mod" knob in LFO2 only. (Towards -5.00)

https://soundcloud.com/adrian-does-digi ... o-rate-mod

Sendy · Post by **Sendy** » Thu Aug 07, 2014 10:49 pm

I noticed this problem a while back, I believe it's a bug and is hopefully scheduled for extermination. I personally don't like it as you can get chaos with the random LFO.

valhallasound · Post by **valhallasound** » Mon Aug 11, 2014 9:22 pm

As far as I know, ANY oscillator with self-modulated FM will go into a chaotic regime, assuming that the FM index is high enough. This was used to generate noise on the DX7.

Sean Costello

Sendy · Post by **Sendy** » Tue Aug 12, 2014 7:44 pm

As far as I know, it never used to happen in DIVA. You could use self-modulation to create exponential versions of the LFO's.

Either it was self-modulation, or cross-modulation between LFO's which got broken in an update. I reported it at the time, but can't remember the details. I'll have another look into it.

Gone soft · Post by **Gone soft** » Tue Aug 12, 2014 10:33 pm

valhallasound wrote:As far as I know, ANY oscillator with self-modulated FM will go into a chaotic regime, assuming that the FM index is high enough. This was used to generate noise on the DX7.

Sean Costello

Not with frequency modulation, only with phase modulation. Frequency modulation only stretches and compresses the waveform in a quite predictable manner. And also it's weird if it only happens with negative modulation. Disclaimer: I don't have Diva, I'm only posting based on what you good people have been reporting here.

Howard · Post by **Howard** » Tue Aug 12, 2014 11:36 pm

Sendy wrote:As far as I know, it never used to happen in DIVA. You could use self-modulation to create exponential versions of the LFO's.

Either it was self-modulation, or cross-modulation between LFO's which got broken in an update. I reported it at the time, but can't remember the details. I'll have another look into it.

Please do - and thanks in advance!

Sendy · Post by **Sendy** » Fri Aug 15, 2014 8:05 pm

Howard wrote:
Sendy wrote:As far as I know, it never used to happen in DIVA. You could use self-modulation to create exponential versions of the LFO's.

Either it was self-modulation, or cross-modulation between LFO's which got broken in an update. I reported it at the time, but can't remember the details. I'll have another look into it.
Please do - and thanks in advance!

It's pretty much as the OP described.

A bit more detail:

1 - It happens at high LFO rates (or at least, it's only plainly hearable at high rates)
2 - Whether negative or positive modulation causes the chaos depends upon which waveform you select: For Saw Down, negative modulation is chaotic and positive is stable. For Saw Up, it's the other way around.
3 - it only affects rate mod, not amp mod.