Digitech Bass Synth Wah
The Bass Synth Wah is Digitech's "bass brother" to the Synth Wah pedal, produced by well-known guitar and bass effects manufacturer, DigiTech. It is a pedal from their X-Series of stompboxes, which include pedals like the DigiTech Bass Driver Overdrive/Distortion, the Multi Chorus and the Bass Multi Chorus, a DigiDelay digital delay pedal, a DigiVerb digital reverb pedal, Turbo Flange, the Main Squeeze and Bass Squeeze compressor pedals, a Hot Rod distortion box and a Hyper Phase phaser pedal, to name a few.
In terms of controls, the Bass Synth Wah and the regular Synth Wah are almost exactly the same. Both have four knobs; The "Sens" knob which controls the sensitivity of the pedal, the "Control" knob, the "Range" knob, controlling the frequency range and the "Type" knob, which sweeps between the 7 synth sounds included in the pedals. Where the pedals do differ though is the synth sounds themselves. The Bass Synth Wah includes the following seven sounds: Envelope Filter, Sub Envelope Filter (which adds another octave to the filter sound), two Synth sounds, two Filter sounds and an OctaSub sound. The pedal features two outputs, meaning two signals can be routed through the pedal; one wet and one dry, with no effect processing.
Chris Wolstenholme uses the DigiTech Bass Synth Wah in his rig ever since the Absolution era but is unknown which song(s) he's using it on.