What to do when the filter cutoff has no effect?

What to do when the filter cutoff has no effect?
« on: June 20, 2020, 03:18:04 PM »
I'm pretty sure this is all user error, but I keep getting myself into a state where turning the filter cutoff know has little to no effect. For example, if you load up the "P5 Bass" patch (F2 P19), where there are plenty of rich harmonics going that could be filtered out. Play C3 and turn the filter knob back and forth... I get no change in timbre. If you play C1 you can get a tiny bit of change. FWIW, the key amount is at 64.

Any idea what's going on? With every other synth I have, turning the filter cutoff to zero completely closes off the signal, unless There's some extreme envelope depth applied to it.

Thanks. :-)


Re: What to do when the filter cutoff has no effect?
« Reply #1 on: June 21, 2020, 02:25:44 AM »
I'm pretty sure this is all user error, but I keep getting myself into a state where turning the filter cutoff know has little to no effect. For example, if you load up the "P5 Bass" patch (F2 P19), where there are plenty of rich harmonics going that could be filtered out. Play C3 and turn the filter knob back and forth... I get no change in timbre. If you play C1 you can get a tiny bit of change. FWIW, the key amount is at 64.

Any idea what's going on? With every other synth I have, turning the filter cutoff to zero completely closes off the signal, unless There's some extreme envelope depth applied to it.

Thanks. :-)

I'll try the patch later (i've overwritten all patches with P08 patches).
The filter cutoff is the combination of all ways you can modulate the filter. So if you have 10 modulations going to the filter with an amount of 100% they all have 10% influence.

jg666

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Re: What to do when the filter cutoff has no effect?
« Reply #2 on: June 21, 2020, 07:20:50 AM »
The Env Amount is at 57 for this patch. If you turn that value down to zero then it might sound more like you’re used to?
DSI Prophet Rev2, DSI Pro 2, Moog Sub37, Korg Minilogue, Yamaha MOXF6, Yamaha MODX6, Yamaha Montage6

Re: What to do when the filter cutoff has no effect?
« Reply #3 on: June 21, 2020, 02:49:13 PM »
I checked that patch too... seems to have a good amount of audible cutoff variation available in its default patch state (from about 0-80 cutoff value)...   Beyond 80, you'll start eclipsing human audio hearing range, since there's cutoff coming from the key amount (+1 per key above C-4) and filter envelope (+57).    Crank up the resonance a bit and there's a ton of squelch.   

You might try running the Global Calibration Routine if you're having an issue on several patches.

The Rev2 uses a straight additive approach for determining cutoff, with Key Amount scaled up from MIDI note 0 (aka C-4).  (some other synths use different math - for example: velocity division of Filter Env Amount, or key amount center points that are different)

Rev2 cutoff math:
Cutoff + Key Amount + Filter Envelope Amount + Env Velocity Amount + Any other Mod/LFO designated to affect cutoff.

If you add all these elements up and they exceed the upper range of human hearing, then any further addition to the elements will have little to no effect... they will essentially be clipped at the upper range.   For instance, a total value of 156 cutoff on the Rev2 = about 8372hz.   For a more in depth look at filter cutoff performance, check out the Appendix F post I created here:   https://forum.sequential.com/index.php/topic,3203.0.html

So, yeah, as jg666 and onelittlefonzie recommended, try turning down filter env amount, velocity, or key amount if you're finding that you want the cutoff knob to have the largest audible range available.   The Rev2 is very flexible, and its possible to clip both the bottom end and top end of cutoff spectrum, which is nice.   


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Re: What to do when the filter cutoff has no effect?
« Reply #4 on: June 26, 2020, 06:44:43 PM »
Thanks to all for the helpful thoughts and suggestions. I think my issue may be with some fundamental understanding of how the Rev2 filter works. Maybe someone can confirm. Here's how I'm experiencing it:

The P5 Bass (F2 P19) factory filter settings are as follows:

  • Env amount: 57
  • Vel amount: 0
  • Key amount: 64
  • Env delay: 0
  • Env attack: 10
  • Env decay: 70
  • Env sustain: 23
  • Env release: 0
  • Cutoff: 12
  • Resonance:9
  • Mode: 4 pole


Based on the suggestions above I change the envelope amount to zero, with the intent of removing any affect the envelope might have on the cutoff value. The cutoff is already quite low, and turning it all the way to zero basically has no audible effect (to my ears); still lots of crunchy harmonics.

At this point I'm confused, because on my other synths if I set the envelope amount to zero (and there's no modulation), and the cutoff value to zero, the filter should be completely closed. So what's left? Key amount is set to 64 (the middle) because I want unity key tracking, and I'd expect to hear some cutoff at C3. I'd expect all the envelope settings to be ineffective because envelope amount is zero. But let's set them all to zero anyway. Might as well turn off resonance. So this leaves me with the following, and still no discernible cutoff:

  • Env amount: 0
  • Vel amount: 0
  • Key amount: 64
  • Env delay: 0
  • Env attack: 0
  • Env decay: 0
  • Env sustain: 0
  • Env release: 0
  • Cutoff: 0
  • Resonance: 0
  • Mode: 4 pole

So we're left with key amount. Turning that down does indeed sweep the filter, just like I would have expected the cutoff knob to do. But I want the key tracking to be just that--˝ or more means C3 gets the LPF as set--not an additional attenuator.

I suspect some of you will be thinking "stop looking at the numbers and just turn the knobs until it sounds right", but for me, I expect to be able to set a nominal filter value, and then modulate that with envelope or key tracking as I refine the sound. With this setup I'm at a loss as to why I have to sacrifice key tracking just to get the filter to engage.

What am I missing?

Re: What to do when the filter cutoff has no effect?
« Reply #5 on: January 15, 2021, 12:40:58 PM »
Hi, is this issue solved? I have the same problem. Checked with init preset ( up + down + hold). The cutoff knob has no effect.
Regards

jok3r

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Re: What to do when the filter cutoff has no effect?
« Reply #6 on: January 15, 2021, 03:30:44 PM »
Hi, is this issue solved? I have the same problem. Checked with init preset ( up + down + hold). The cutoff knob has no effect.
Regards

If this problem occurs with the init patch, I don't think it has something to do with the above issue. In an init patch there are no modulations set, that could cause this effect like in the P5 bass patch.

Do you have connected a foot controller or any other gear that will modulate cutoff from extern? I don't have a foot controller here right now, but I would guess if you set a foot controller to control cutoff per globals menue, and have it lying on the floor fully open, that it will "overwrite" your cutoff knob, since all modulations add up.
Prophet Rev2, Moog Matriarch, Novation Peak, Arturia DrumBrute Impact, Korg Kronos 2 88, Kurzweil PC 361, Yamaha S90ES

Re: What to do when the filter cutoff has no effect?
« Reply #7 on: January 16, 2021, 05:19:37 AM »
Hi jok3r,

thanks for your quick reply. In short: it works again now!

Explainations:
I connected a foot controller to sustain input, thats true. And I also disconnected it, to exclude issues like this. But the problem was still there.

Next I checked was:
- creating an init patch (up+down+hold) so nothing is assigned. In this state, the cutoff knob did not work.
- then tried to do a simple lfo modulation: press and hold LFO 1 and turned the cutoff knob. On full clockwise the display said, that cutoff was assigned. This means to me, that the knob is still working.
- Then increased amount and lowering frequency of lfo 1 modulation. And, ok, now the pure init saw was modulated. So this means to me, the filter is working. But the cutoff knob does still has no effect.

Then I was looking for settings in global menue and misc menue, that effect the pedal, sustain and arp/seq. But I could not find anything.

I decided to do a midi dump to save my presets and after that to do a global reset of the globals.

So I turned on MIDI-OX (on Win 10 connected over USB) and did a manual dump from rev2 to MIDI-OX. After this, I checked the received data and send them back to rev2. This took a while and I could see, that the the presets were triggering ones after the other.

And now, surprise, the cutoff knob is working again like before. Also with the pedal to sustain connected.

So this is not an explaination of the causes, especially because the midi sysex dump should only replace the preset data and not the globals or something else. But ok, maybe a workaround for other people with this issue.

have a nice weekend
earthroom



Re: What to do when the filter cutoff has no effect?
« Reply #8 on: January 16, 2021, 10:13:32 PM »
I have had the same filter issue a few times, and there have been two things that have caused it for me. it happened when I was controlling the Rev 2 via MIDI and an external keyboard. it also happened when I had the expression pedal set to control filter cutoff in the global menu with the pedal set to the maximum setting. keep in mind that when you change programs on an external midi keyboard, even if program change messages are disabled, as long as control change messages are enabled they can affect parameters such as cutoff on the Rev 2. I wish there was a way to filter out specific control change messages on the Rev 2 so this wouldn't be an issue. I had to create a workaround on my other keyboard to resolve the midi issue with the filter.