Alexander Pedals Colour Theory Spectrum Sequencer Pedal

Written by

Ben Greener

The Colour Theory.  Each step in its sequence is a new pathway to adventure, each new colour is part of a palette of mystery.  Every moment brings a new surprise, as the patterns cycle and interact.

The Colour Theory combines a versatile eight-step sequencer with a powerful effects processor, creating rhythmic combinations seldom heard outside of a rack of synths.  It’s small but mighty, utilizing our Neo Series technology in a completely new way.

Alexander Pedals - NAMM 2018

What is a Step Sequencer?

Imagine a drum machine that plays different sounds on each beat - kick, snare, kick, snare.  Now replace those drum sounds with pedal settings, and you’re getting close.

The Colour Theory allows you to preset different values for its effects - each step of the sequence may be set to any values you like, so as the sequence plays the effect changes automatically.  You can set the Colour Theory to play a series of tones in OSC mode, or to open and close a filter in FLT mode.  The only limit is your own imagination.

Neo Series:

The sonic scientists at Alexander Pedals have been working overtime to cram the most pedal into the smallest box, and we now present the Neo Series!  Each Neo Series pedal incorporates an advanced 32-bit microcontroller adding presets, expression, and MIDI capability.

The Neo Series pedals are small but mighty!  Imagine having a single pedal on your board that can access up to 4 separate preset tones with a touch of your toe.  Connect an expression pedal to "morph" between two distinct settings for each preset for dynamic real-time effects.  Or connect the Neo Footswitch to enable your choice of preset select, tap tempo, or start / stop the sequence in real time.


All Neo Series pedals feature a simple yet powerful preset functionality.  Hold the bypass footswitch to move the pedal to the next available preset, and the pedal will reconfigure itself on the fly.  All knob values and the effect mode settings are recalled, allowing you to set up to four unique tones.  Want more presets?  Simply connect a MIDI controller to the EXP port on the side of the Neo Series pedal and access up to 16 presets total.

To load a preset, hold the bypass footswitch down or send a MIDI program change from 0-15.

To save a preset, hold the Select button down and then hold the bypass footswitch.  The pedal will save the current settings to the current preset.

Any changes you make to the pedal settings will be lost when switching to a new preset unless you save the current preset first, so be careful!

Expression and MIDI:

The EXP port on the left side of the pedal can function as an expression pedal, foot switch input, or a MIDI input.

Expression Pedal:  Set the expression pedal to the heel down position, then adjust the knobs to your preferred setting.  Sweep the pedal to the toe position and set the knobs to a different setting.  The Colour Theory allows the user to sweep the Rate, Steps, Mix, and Lag controls with the expression pedal or ramp footswitch.

Foot Switch:  The Neo Footswitch (sold separately) allows for preset select, tap tempo, or sequence start / stop control - all with LED indication.  The Colour Theory will also work with a standard tap tempo footswitch.

MIDI:  The Neo Series pedals can connect to a compatible MIDI controller to control all of the pedal functions plus access 12 extra presets, for a total of 16.  The USB port may also be used as a MIDI interface to your computer or mobile device.


Controls in parentheses () are accessed by holding down the Select button and turning the indicated knob.

Rate:  Controls the speed of the step sequencer.  Step size ranges from two seconds to 50 milliseconds.  You can set the step size larger than two seconds by using the tap tempo footswit

(Ext Ctl):  Controls the value of the external control output, either MIDI or control voltage.  This parameter is sequenced.

Steps: Selects the number of steps the sequencer will use, from two up to eight.

(Value):  Controls the main parameter of the selected effect - pitch, delay time, filter frequency, tremolo rate, oscillator pitch, or PWM divider amount.  This parameter is sequenced.

Mix:  Controls the blend between the dry and effected signal.  Equal mix is at 12 o'clock.

(Amount):  Controls the mix of each sequenced step.  The Mix and Amount controls allow the user to set up a sequence with any Amount of effect, and then fade the sequence in with the master Mix control. This parameter is sequenced.

(Level):  Controls the overall output level of the pedal, from -20dB to +10dB.  Unity gain is near 1 o'clock.

Lag:  Adjusts the smoothness of the steps for the sequencer.  Higher lag settings cause the effect parameters to "glide" between values, lower settings produce a more jagged or "stepped" effect.  Please note that the Lag control has no effect on the Value parameter for the PWM mode.  Just saying.

(Tweak):  Adjusts the secondary parameter of the selected effect - tone control, delay feedback, filter resonance, tremolo wave shape, oscillator waveshape, or PWM modulation.  This parameter is sequenced.

Select Button - tap to choose a new effect mode:

PIT - Sequenced pitch shifter.  This effect can create harmonies or pitch shifts, with any interval from 1 octave down to 1 octave up.  The pitch and tone of the effect signal may both be sequenced.

MOD - Sequenced digital time modulation.  The delay time ranges from 0 milliseconds to 300 milliseconds, and both the delay time and feedback may be sequenced.  Try the delay effect with two steps and a high lag to create a very lush chorus or vibrato.

FLT - Sequenced resonant filter.  This is a low-pass filter that can have high levels of resonance, to the point of oscillation.  Be careful, this thing can get wild at extreme settings.  Filter frequency and resonance may both be sequenced.

TRM - Sequenced tremolo.  Create rhythmic patterns or insane stutter modulation with this one.  The tremolo rate and waveshape may both be sequenced.

OSC - Sequenced synth oscillator.  This is useful for making melodies or whacked-out siren sounds.  The pitch range is a couple of octaves, and even "in-between" notes outside the normal tempered scale are available.  Value controls the pitch and Tweak blends between sine and square wave shapes.  We promise your neighbors will hate this mode.

PWM - Synthesized octave effect.  Don't know why we thought this would be cool, but here you go.  This mode turns your guitar signal into a monophonic digital square wave, with the divider rate set by Value.  This will get DOWN, to subharmonic levels.  It's kind of nuts.  The Tweak knob controls a modulation effect on the synth wave.  Try this for making your neighbors hate you even more than OSC mode.

Bypass Switching:

The Colour Theory features a buffered bypass using a soft-touch footswitch.  The dry signal path is digital because computers. The bypass signal is 100% analog.


To configure, power on while holding the center Select button and release when the program LEDs start to flash.

Tap the Select button to choose Expression (upper LED green,) Foot Switch (upper LED orange,) or MIDI (upper LED red.)

Turn the Delay knob to select the function for the Neo Footswitch - Counterclockwise for sequence start / restart, center for preset select, clockwise for tap tempo.

Turn the Mix knob to select the Foot Switch Ramp speed - Lower LED green slow, lower LED orange medium, lower LED red fast.

Turn the Tweak knob to set the main LED brightness.

If you wish to assign the Colour Theory MIDI channel, simply send a program change message from your controller on the correct channel while the pedal is in configuration mode.  Hold the Select button to save the pedal settings.

The Colour Theory MIDI port requires the use of either a MIDI converter box such as the Disaster Area / Chase Bliss MIDIBox or a MIDI controller that supports 1/4" devices such as the Disaster Area Gen3 series.  The Colour Theorydefaults to using MIDI Channel 1.

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