The Official Sequential/DSI Forum

Strange distortion with the state variable filter in paraphonic mode

kyps

Hi everyone,

Just got the pro3 yesterday and itís really amazing !!!
Iíve just encountered a trouble with mine,

Is that normal to get some abnormal distortion when you turn on to the maximum the resonance, 50% the filter cutoff in state variable filter (ob6 filter) when you play some chords ?
My master volume is around 25% and they didnít affect the behaviour

Iíve tried with an initial patch 3 saw at normal volume. Without any effect

Also, itís more happening when paraphonic mode is on

Someone have the same issues please ?

Thanks
« Last Edit: July 22, 2020, 06:51:45 AM by Sacred Synthesis »

Itís normal to get distortion when the oscillator levels are high, i.e. past noon or so. Itís not really an issue itís just normal gain staging behavior. But many synths limit volume at certain stages to prevent distortion. Dave just lets her rip.

kyps

Sorry as I said,
The master volume is to 25% so pretty quiet
Then the oscillators are around 60/70% of the maximum volume

Sorry as I said,
The master volume is to 25% so pretty quiet
Then the oscillators are around 60/70% of the maximum volume

I see distortion in the filter from high signal levels as well, it has taken me some time to learn to recognize and fix it.

The master volume is only the output from the instrument, it is not the oscillator level into the filter. The high oscillator levels into the filter is likely what is causing the distortion you see, not the master volume level. So also turn the individual oscillator levels down to 20-30% and see if the clipping goes away. 60-70% is way above the 12 o'clock (i.e. 50%) maximum being suggested.

As mentioned above by @guyaguy... this is a gain staging exercise. 

You can probably just turn down the Individual Osc mix levels further... I've got several paraphonic patches where I'm down near 50-60% volume for Osc 1/2/3 mix levels.   I have noticed that in paraphonic patches I almost always turn down osc mix levels... (I'm guessing that in standard mode / non-paraphonic mode, there might be a little bit of attenuation added to the other oscillators when you turn up others... and this attenuation is not present in paraphonic mode) - not sure if that's correct, but I wouldn't be surprised if that's the case.   

Also check your other sources going into the filter.   If Ext In is turned up that will be adding natural feedback that can overdrive the filter.   And of course check Filter Drive, Tuned Feedback and Distortion to make sure you're not unexpectedly getting those gain sources in your mix. 

Some synths do all the gain staging work for you by attenuating parts of the mix based on parameters set, but this unit really gives you extensive control over the signal path and gain staging...   for more advanced sound programming this type of setup is preferred because you can purposely push levels with various different methods... allowing for a wide variety of more aggressive tones, or just hitting the filter a bit hot for a slight overdrive.   

Sequential Pro 3 and Rev 2 - Sound Sets and Patch Banks - Now Available on Sellfy: https://sellfy.com/sounddesign/

kyps

Thanks a lot that works !!!!! Love this synth !!!!

Moho

Also watch your Amp Amount as it can cause distortion in the FX, and not the nice kind.