Hello,
I tried in all the ways to change parameters of Wah effect on a performance but nothing happens.
How is possible to accelerate the Wah effect? I just found three kinds of Wah but no one let me change the speed of the effect.
Thanks for helping me!

Hi Fabio, you are correct in only one thing... There are three kinds of Wah Effects in your MODX... these are the VCM (Virtual Circuitry Modeling) Effects.
VCM PEDAL WAH
VCM TOUCH WAH
VCM AUTO WAH

Each does its thing a little differently. On the off chance you don’t know how a Wah-Wah pedal works — it is a foot controlled device that is a frequency Filter with a moveable Cutoff Frequency and a Resonance parameter. The Filter will allow certain audio frequencies to pass while it blocks others; the Resonance represents an amplitude increase (level) at the Cutoff Frequency - it emphasizes that frequency giving the Wah-Wah a distinctive sound. In an actual Wah-Wah pedal, the movement of the Filter Cutoff Frequency is determined by the position of the foot Pedal. The Pedal can perform a filter sweep...

What the VCM Wah Effects offer is three different methods of generating Wah-Wah.

Just looking at the names of the three Wah-Wah Effect types listed here, you can begin to understand that only one of them would respond to a change in acceleration thus changing the “speed of the effect”. The speed of an actual guitar player’s Wah-Wah would be determined by the muscles in the player’s leg and the action of their ankle... as the speed is up to the person applying movement to the Pedal.

The “VCM Pedal Wah” would be the one that requires you actually have an FC7 pedal plugged in to the MODX, and assigned control this effect, so you can manually control the Speed of the Filter Cutoff Frequency change. Thus the name “pedal”

The “VCM Touch Wah” works the Cutoff Frequency speed by your playing style... the act of touching the key would cause the change. The more energy you put into playing causes a greater response in this movement and therefore the effect. Thus the name “touch”.

“VCM Auto Wah” you can automate the movement of the Cutoff Frequency. This one is different from the other two, because the Cutoff Frequency moves with or without your influence. In the Pedal Wah you must move the filter manually, in the VCM Touch it is sensitive to your interaction with the keys. Here in the Auto Wah an LFO (Low Frequency Oscillator) is applied to move the Cutoff Frequency automatically. Thus the name “auto”.

This means the Cutoff Frequency is constantly in motion... even when you are not touching the Keys, or the FC7... instead as you play the Filter is applied to the sound. Obviously you can not hear the modulation in Frequency until you run audio signal through the system... the movement then manifests itself on the resulting sound.

Now let’s review your question. What are you looking to change? Speed
Well according to the descriptions only one of the three types will even have a SPEED Control or an LFO - and of course that is the VCM AUTO WAH.

Extra Credit:
How to look this up... Find your MODX Data List booklet (pdf). If you didn’t download this document, be sure to go to the Official MODX Download Page and get a copy. Search for EFFECT PARAMETER LIST ... on page 153 you’ll find the three Wah Types. Of course, you can see the parameters in the MODX, but the Data List booklet lets you see and easily compare the differences between the three Wah Effect Types. (Hint: when new Effect Types or new features are added via firmware updates, typically a new Data List booklet is made available adding the new features and their parameters).

VCM Auto Wah the first parameter is “Speed” and it has an LFO parameter to automate that speed of movement.
VCM Touch Wah has “Sensitivity” in place of Speed because the movement is determined by you striking a Key.
VCM Pedal Wah has “Pedal Control” in place of Speed, or Sensitivity, because you are manually going to move the Cutoff Frequency with a foot pedal (FC7).

So looking for a parameter that will influence the Wah-Wah is the first parameter in each listing. Once you know what a Wah-Wah actually does it is a no-brain er (hopefully) to adjust the Speed of the Wah-Wah — you just need to be looking at the right Effect Type.

Thanks for the question. Hope that helps.

Additional reading — Links For Reference:
How to assign Wah

More on the VCM Wah Effect