Where the original Blue Box gave a preset two-octaves drop in pitch, alongside a simple control set of output and blend knobs, the Poly Blue offers a comprehensive set of controls.
For a start, the clue is in the name, as the Poly Blue is polyphonic (although it can also be switched to work in monophonic mode). The pitch effects within the pedal have been separated out, with dedicated level controls for sub-octave one and two, as well as two additional controls for blending in one and two octaves above the note you’re playing - that’s a four-octave range in total!
Once you have the blend of octaves you’re looking for, you can feed the whole lot through the Poly Blue’s modulation circuit to add some synth-like movement and texture.
Of course, we mentioned earlier that the Blue Box was an octave/fuzz pedal, and the Poly Blue also includes a switchable fuzz circuit too. There’s a ‘dry’ control that allows you to blend your un-effected signal in, plus it doubles as a volume level control for the fuzz circuit when combined with a held-press of the fuzz toggle switch.
As well as the sound-sculpting options, MXR has equipped the Poly Blue with an expression pedal socket which can unlock some sophisticated control options.
For example, connecting a TRS cable from an expression pedal into the Poly Blue’s Expression jack lets you crossfade between two different pedal configurations in the heel-toe positions. This means you could jump between octave down and two octaves up - or any other combination of the controls - without having to change any settings.
Similarly, if you want handsfree control of the fuzz toggle switch, you can connect a regular tap switch into the expression socket and use it to switch the fuzz circuit on and off, or change from polyphonic to monophonic mode.
We’re expecting the MXR Poly Blue to be priced at £199/$199, with retailers already accepting pre-orders.