October 2024: Fractal Audio's VP4 Virtual Pedalboard has been added to the wiki.
Wah block
Contents
Available on which products
- Axe-Fx III: 2 blocks
- FM3: 2 blocks
- Axe-Fx II: 2 blocks
- AX8: 1 block
- FX8: 2 blocks
Channels or X/Y switching
- Axe-Fx III and MF3: 4 channels
- Axe-Fx II: X/Y
- AX8: X/Y
- FX8: X/Y
Wah types
- FAS Standard – equivalent to the “Bandpass” setting in earlier firmware
- Clyde – based on an original Vox Clyde McCoy wah
- Cry Babe – based on a Dunlop Cry Baby
- VX846 – based on a Vox V846-HW handwired wah
- Color-Tone – based on a Colorsound wah
- Funk – based on the “Shaft” sound
- Mortal – based on a Morley wah/volume pedal
- VX485 – based on a Vox V845
Pictures of the real pedals, by MDProd
Other Wah pedals can be emulated by copying frequency range settings from the manufacturer's data:
Position of the Wah block on the grid
Just like actual Wah pedals, the Wah block is usually placed before the amp.
Unless you want to sound like Tom Morello, in which case it should be placed after the Amp block.
Set up a Wah pedal
Read this: Remote control, pedals and switches
Make sure to calibrate the pedal on the hardware!
Auto-engage the Wah
Similar to an optical Wah pedal, you can engage the Wah block automatically when moving the assigned expression pedal. Especially handy when using a spring-loaded pedal. To accomplish this, set Auto-Engage in the modifier menu of the CONTROL parameter in the Wah block to either a speed or position controlled setting. More information
Parameters
Parameters table
| Parameter | Axe-Fx III / FM3 | Axe-Fx II |
|---|---|---|
| Type | yes | yes |
| Wah Control | yes | yes |
| Control Taper | yes | yes |
| Resonance Q | yes | yes |
| Q Tracking | yes | yes |
| Low Cut Frequency | yes | yes |
| Minimum and Maximum Frequency | yes | yes |
| Fat | yes | yes |
| Drive | yes | yes |
| Inductor Bias / Coil Bias | yes | yes |
| Graphic EQ | yes | no |
Tracking
"Tracking controls how much the Q changes with the Control knob. The Q in a wah is not constant. The amount of Q change varies from brand-to-brand and model-to-model. It even varies between identical models due to component tolerances." source
Fat
"FAT is actually a mix control. It adds dry signal so you can't ever get 100% dry. At max FAT it's 50/50." source
Max Freq
Decreasing the maximum frequency allows a high gain Wah tone to cut better through the mix.
Coil Bias / Inductor Bias
This allows the user to adjust the DC offset of the virtual inductor.
"Over time the inductors build up some slight permanent magnetism due to finite DC current through them. This causes asymmetric distortion." source
EQ
8-band Graphic EQ (firmware Ares).
Output Level
When changing the Wah type, the output level is adjusted automatically because the output of the models has been matched to the original pedals. source
"A typical wah has a gain of around 16 dB but it's a bandpass (sort of) response. If your amp is set clean then the output of the amp block will increase by 16 dB when the wah is engaged. Most amps have a response that rises with frequency response. So if the output of the amp block without the wah engaged was, say, 12 dB below full-scale at the high frequencies, it will be 4 dB over full-scale when the wah is engaged." source
Tips and tricks
Seek Wah
The Seek Wah is a pedal by ZVEX, which is based on a sequenced filter pattern. For an equivalent effect, assign the Sequencer internal controller to the Wah Control parameter. For a more pronounced effect, add a Formant block, attached to the same controller.
Auto Wah
Read this: Filter block
Fixed Wah
Simulate a fixed Wah position (think "Money For Nothing" by Dire Straits) by setting the Wah Control parameter to a fixed value.
Slow filter
Attach the LFO internal controller to the Wah Control parameter in the Wah block to create a slow evolving filter effect.
Solving the thump when engaging the Wah
Engaging the Wah can cause a low frequency thump. This is related to Input impedance.
"The thump isn't the wah, it's the Input Impedance changing. If your preset is set to Auto for the Input Z, when you engage the wah the impedance switches. This causes a slight thump if you are playing since the load on your guitar changes. If you want to avoid this, turn Input Impedance to 1M OHM." source
"Set the Input-Z on the preset to 1M rather than Auto. The reason the Wah engages abruptly is because it switches the input impedance. Setting Input-Z to 1M overrides the impedance switch (and, frankly, sounds better IMO)." source
The above doesn't apply to Fractal Audio processors with a fixed (not adjustable) input impedance.
