MXR Bass Auto Q

The MXR Bass Auto Q is fundamentally an auto-wah effect - with a twist. It runs on a wall-wart (not supplied) or a PP9 battery, and the controls are neatly, if unfortunately, arranged in a scowl. Volume is joined by Range (how low the effect goes) and Q (wah intensity), and on the right there's Decay (how long the wah effect lasts relative to note sustain). The remaining controls relate to the Auto Q's secret weapon - a variable ‘shimmer' effect akin to tremolo. Blend controls the mix of wah and trem (left for wah only, right for trem only) and Rate handles the intensity.
Isolate the wah effect and it's space funk all the way. Rotating Q clockwise adds a snappier edge to the wobble while Decay dictates how quickly the gurgle kicks in and peaks: the best area is central or on the anti-clockwise side. The shimmer/tremolo comes in slowly so it's best suited to held notes, chords and pauses in phrasing. If you shred, you don't really notice it - but with held notes and especially harmonics in either scenario, it adds an interesting colour to the tonal palette with a nice three-dimensional quality.

The Auto Q is a little pricey, but what it delivers just about justifies it. The shimmer element is cool, if a little limited, but the auto wah delivers a huge variety of gurgling, snappy sounds that'll keep diehard Parliamentarians happy for a lifetime. Geezer Butler would love this pedal, too.