Incorrect behavior of Random waveform from LFOs

Incorrect behavior of Random waveform from LFOs
« on: December 11, 2017, 06:37:10 AM »
For the last hour I've been trying hard to replicate a rather simple patch from an Oberheim 8V, as can be heard on Rush's Camera Eye song.

It's seven notes played, on which the filter cutoff (with moderate resonance level) is gradually being modulated by an LFO with Random S&H.

The problem is that the random values from the LFO are different for each voice's filters. Resulting in a mish-mash of filter modulation, instead of the typical unified Random S&H changing values, that can be heard with all other waveforms of the LFO.

The Behringer DeepMind 12 had the same "problem" when it first came out, but after mentioning this to the developers, they quickly corrected the behavior, in a firmware update, as to reflect all other LFO waveforms, and output the same random value for all voices for each clock step of the LFO.

I don't suppose DSI developers would be open to do the same for the REV2 ?
Oberheim OB-X8, Minimoog D (vintage), OB6 (Desktop), Oberheim Matrix-6 (MIDI Controller for OB6), VC340

Re: Incorrect behavior of Random waveform from LFOs
« Reply #1 on: December 11, 2017, 06:41:12 AM »
Rather than chat here, you should reach out directly to DSI via their support channel.

Razmo

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Re: Incorrect behavior of Random waveform from LFOs
« Reply #2 on: December 11, 2017, 06:49:54 AM »
This seems like being related to what others have been asking about the LFO's... that they can be set up to be "global" for all voices... many have requested that feature, but it's ultimately up to DSI to hear the peoples wishes and do something about it.... at the same time, the REV2 LFO's have bugs that DSI have fixed to a certain degree... they have also decided to look more into these bugs, so all you can do is wait, and hope that they will add a global sync mode for the LFO's between voices.... and it certainly will be adviceable to write your wishes directly to support as well... the more who ask for it, the bigger the chance we'll see it happen.
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Re: Incorrect behavior of Random waveform from LFOs
« Reply #3 on: December 11, 2017, 06:53:32 AM »
Morganspaziergang and Razmo,

Good point. It's been done now, thanks.

« Last Edit: December 11, 2017, 07:01:03 AM by AlainHubert »
Oberheim OB-X8, Minimoog D (vintage), OB6 (Desktop), Oberheim Matrix-6 (MIDI Controller for OB6), VC340

Re: Incorrect behavior of Random waveform from LFOs
« Reply #4 on: December 11, 2017, 09:38:18 PM »
Got a reply from Carson Day of DSI Support today about it:

"Hi Alain,

Thank you for your inquiry, I would be happy to assist you. The LFOs in the Prophet REV2 are per voice and not global. This is why the LFOs track differently per voice. This is how most of our polyphonic synthesizers behave except for the Prophet 6 and OB-6.

That said, I would be happy to add your suggestion for a global LFO mode to our feature request list. I, however, have no information regarding when/whether this would be implementable.

I hope this helps! Thank you for supporting DSI and have a nice day!

Thank you,

Carson
Dave Smith Instruments"

So let's hope that they'll consider this request and add it in a future firmware update... Fingers crossed.

After all, the Prophet 5 that started this whole family of Prophets had a single global LFO, much like all the other synths that followed in that era.
 
« Last Edit: December 11, 2017, 09:39:50 PM by AlainHubert »
Oberheim OB-X8, Minimoog D (vintage), OB6 (Desktop), Oberheim Matrix-6 (MIDI Controller for OB6), VC340

Re: Incorrect behavior of Random waveform from LFOs
« Reply #5 on: December 12, 2017, 03:02:46 PM »
Yeah this is a pretty basic function in most synths, even the Behringer DeepMind had the same issue than Fixed it, come on DSI you are better than Behringer!