I'm trying to do a cutoff fade that goes all the way to 20khz but using the Zxx sounds weird cuz it goes until 5k and then off so the high range doesn't fade in smoothly.
Is there any other way of doing this cutoff fade effect?
The Impulse Tracker resonant filter indeed only goes to about 5kHz (or 10kHz with extended filter). If you want more control, you need to use a filter plugin.
Oh alright, thanks a lot for the info ^^