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Predator CC1 to Cutoff Modulation Anomaly

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Moderators: Meffy, Concretefx, Rob Papen

14 posts since 20 Feb, 2012

Postby rtz; Mon Feb 20, 2012 1:23 pm Predator CC1 to Cutoff Modulation Anomaly


I'm finding the following unexpected behavior in Predator v1.5 running on PT (RTAS) as well as v1.6 on Logic (AU): when the modwheel is set to modulate cutoff in the Free Modulation section (in this case, modulation slot #1) and under the conditions described below, the filter takes on a bit of a "wah" effect as though it were being modulated with an envelope with a slightly slow attack. This occurs even when there's no envelope-->cutoff modulation. However, when CC#1 is assigned directly to the cutoff control, this "wah" effect doesn't occur.


1) start with a completely zero'd patch with no modulations of any kind save for Amp envelope set to "gate" (zero attack, full sustain, zero release). Enable one oscillator, sawtooth, no spread. ECS cleared. Filter response = 12 LP

2) set Cutoff to 410 Hz or thereabouts

3) Free Modulation #1: assign modwheel --> filter frequency, depth zero. Move the modwheel to ensure that no modulations are taking place.

4) now set the Free Mod #1 amount to 50% and move the modwheel slowly up to mid position, playing as you do this. You'll hear a soft "wha" sound as the note attacks.


5) clear Free Mod #1 by setting the source to "none" or setting the modulation amount to zero. Then assign CC#1 to the Cutoff control directly

6) move the modwheel slowly upward as you play and you'll hear that the attack is sharp and clean (as expected) with no "wha"

Wondering if the sound produced in steps 1 - 4 is normal behavior and part of the character of Predator, or if something's not quite right.


Peter Schwartz
3563 posts since 6 Feb, 2003, from UK

Postby Concretefx; Tue Feb 21, 2012 2:59 am

Hi there

This might be down to how the modulation are set and their rate, but we haven't had other reports. I'll need to investigate.


14 posts since 20 Feb, 2012

Postby rtz; Tue Feb 21, 2012 10:06 am

Hi Jon,

Thanks for your reply!

I'll be curious to know if you find the same behavior and if a fix is possible. Case in point as to why this is problematic:

On the track I'm currently producing, I have Mod Wheel --> Cutoff (as described above in the Free Mod section) to open and close the filter during a fast 16th note sequence/pattern created with Predator's arpeggiator. The sonic character of the notes gets "mushy" when I open the filter because of the wah effect I described. This didn't happen when I assign the modwheel to the filter directly (the notes' attacks were sharp, perfect, as expected). So that's my workaround for now, but it's not a convenient solution for many reasons, including the fact that I can't set a static value for filter cutoff (as it's always under CC control).


3563 posts since 6 Feb, 2003, from UK

Postby Concretefx; Wed Feb 22, 2012 12:06 am

As in the other this is something I will be able to investigate after Blade is out.



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