Wah block

Wah block

Axe-Fx III: 2 blocks, 4 channels
FM3: 2 blocks, 4 channels
FM9: 2 blocks, 4 channels
VP4: 4 blocks, 4 channels

Axe-Fx II: 2 blocks, X/Y
AX8: 1 block, X/Y
FX8: 2 blocks, X/Y

Wah types

1. Clyde – Original Vox Clyde McCoy wah.
2. Color-Tone – Sola Colorsound wah.
3. Cry Babe – Dunlop Cry Baby.
4. FAS Wah – Fractal Audio's custom Wah model.
5. Funk Wah – Sound from the “Shaft” movie.
6. Mortal – Morley wah/volume pedal.
7. Paragon – Tycobrahe Parapedal.
8. VX485 – Vox V845.
9. VX846 – Vox V846-HW handwired wah (Stevie Ray Vaughan).

The sound of other Wah pedals can be reproduced by copying data from the manufacturer's data and entering these values in the appropriate Wah model. See these discussions in the forum for more information:

• Petrucci and Cantrell Wah
• Anyone dialed in a good Budda Bud Wah block?

And look up values on Sweetwater's website.

Position 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 the expression pedal

You need an expression pedal. Always connect the expression pedal with a TRS to TRS stereo jack cable. Read Expression pedals and external switches for more information. The Owners Manuals have a tutorial on setting up a Wah pedal in the Modifier section.

Always CALIBRATE the pedal on the hardware. This makes sure that the full sweep of the pedal is being used. To do this, make sure you're using the correct menu. This depends on the physical connection of the pedal:

• Axe-Fx, FM3, FM9 and VP4: use the PEDAL section in the Setup menu.
• FC controller: use the FC Controllers section in the Setup menu.
• MIDI controller: use the calibration function on that controller.

If you want the expression pedal to perform more tasks than a Wah only, read Expression pedals and external switches to learn more.

Auto-engage the Wah

Similar to an optical Wah pedal, you can engage the Wah block automatically when moving the pedal. This is especially handy when using a spring-loaded pedal. To accomplish this, set Auto-Engage in the CONTROL parameter's modifier menu in the Wah block to either a SPEED or POSITION-controlled setting.

To turn off the Wah at toe down position, instead of heel-down, set OFF VALUE to 95%.

In current firmware, the Wah engages and bypasses with a gentle fade instead of an abrupt on/off.

Parameters

Control and Taper

CONTROL controls the sweep.

TAPER selects the curve of the sweep. The taper number, 5, 10, 15, 20, 30, is the percentage at the halfway point; LOG 20A means that the resistance is 20% at the halfway point in the travel. So if you put the knob at noon, it would be 20% of maximum.

Maximum Frequency

Lowering this allows a high gain Wah tone to cut through the mix better.

Inductor Bias (Coil Bias)

Adjust the DC offset of the virtual inductor.

FRACTAL AUDIO QUOTES

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[1] Over time the inductors build up some slight permanent magnetism due to finite DC current through them. This causes asymmetric distortion.

Fat

FAT is a mix control. It adds dry signal. You can't ever get 100% dry, at max FAT it's 50/50.

FRACTAL AUDIO QUOTES

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[2] If you like Wah with a Mix, just use the FILTER block. You have the option of LPF or BPF, adjustable Q, plus a ready-to-use Mix control. You'll need to set MIN and MAX in the Modifier rather than with knobs, but that's not hard.

Q Tracking

FRACTAL AUDIO QUOTES

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[3] 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.

Graphic EQ

8-band Graphic EQ.

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.

FRACTAL AUDIO QUOTES

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[4] The levels were matched to the actual pedals.

[5] 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.

[6] A Wah boosts the volume at the center frequency. The cleaner the amp the less compression. A real amp would do the same thing. The easiest solution is to simply turn the level down in the wah block.

Tips, tricks and troubleshooting

Factory presets

Many Factory presets have a Wah block.

Auto Wah

See "Filter block".

Touch Wah

See "Filter block".

Seek Wah

The Seek Wah is a pedal by ZVEX, which uses a sequenced filter pattern. For an equivalent effect, assign the Sequencer controller to the Wah's CONTROL parameter. For a more pronounced effect, add a Formant block, attached to the same controller.

Try this factory preset: S/HIP AHOY.

Fixed Wah

To create the sound of a fixed Wah position, such as in Money For Nothing by Dire Straits, set the CONTROL parameter to a fixed value.

Try the MONEY FOR SOMETHING factory preset.

Slow sweeping Wah

Attach the LFO internal controller to the CONTROL parameter in the Wah block to create a slow evolving filter effect.

Try the VELVET SUN factory preset.

Input impedance

Variable Input Impedance in the Input block can cause a low-frequency thump when engaging the Wah. Read Input impedance for more information.

Alternative to Auto-Engage

For an alternative approach to Auto-Engage, load Devin Townsend's preset from the Fractal Audio Gift of Tone series or try the HEVY DEVY factory preset.