Always consult the Owners Manuals and FAQs first.
FM3 information is being added as it becomes available, but it's preliminary and not final until release

Phaser block

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Phaser block.png

Available on which products

  • Axe-Fx III: 2 blocks
  • FM3: yes @@
  • Axe-Fx II: 2 blocks
  • AX8: 1 block
  • FX8: 2 blocks

Channels or X/Y switching

  • Axe-Fx III and FM3: 4 channels
  • Axe-Fx II: X/Y
  • AX8: X/Y
  • FX8: X/Y

Phaser types and effects

Script and Block

These types are based on the MXR Phase 90 and Phase 45, Script and Block versions.

The "Phase 45" type uses subtle two-stage phasing, while the "Phase 90" type uses more pronounced four-stage phasing.

The "Script" type has a more subdued sound with higher headroom and greater clarity. The "Block" type is more modern and relies on internal feedback to create light harmonic distortion and give the effect a more accentuated swoosh.

Forum member Guitarnerdswe created even closer digital replicas of the MXR Phase 90 (script and block) by attaching an LFO to the Start Frequency parameter. Read more


The Uni-Vibe effect is available as a special mode of the Phaser block. Engage the Vibe mode (or select the Classic Vibe type).

The default settings are modeled after the Fulltone Deja-Vibe. source

More settings:

Put the effect before the Amp block.

"You need it before the amp if you want the bump." source

Connect a pedal or switch to the Rate parameter to control speed.

More information:

Barber Pole

Like the "Shepard tone", this type creates the illusion of a never-ending upwards cycle. Works best when placed at the end of the chain.


Set the Phaser to 6 stages to emulate a Mutron Bi-Phase.

"For the double-phaser of the original, set it to 12-stage with LFO Phase at 0." source

Step Phaser

To simulate a stepped phaser, set Depth to 0, attach Frequency Start to the Sequencer, set Min and Max and adjust the Sequencer faders.

Mono or stereo Phaser

Phaser defaults to mono to prevent phase problems when used before an Amp block.

To make it stereo, change the LFO Phase setting and place it after Drive, Amp and Cab.

Thump when engaging the Phaser

Engaging some effects, like Wah or Phaser, can cause a "thump" in the sound. This may be caused by impedance switching. To solve this, change Input Impedance from "Auto" to "1M". The above doesn't apply to Fractal Audio processors with a fixed (not adjustable) input impedance. Read this: Input impedance


Parameters table

Parameter Axe-Fx III / FM3 Axe-Fx II AX8 / FX8
Type yes
Rate yes
Tempo yes
Depth yes
Feedback yes
Start Frequency yes
Phaser Mode yes
Order yes
Frequency Span yes
LFO Type yes
LFO Phase yes
Bulb Bias yes
Feedback Tap yes
Tone yes
LFO Reset on Bypass yes
Barberpole — Sweep Direction yes
Barberpole — Filter Q yes


"Phasers cause notches in the spectrum which can reduce the apparent volume. It depends on the frequency content. Overdriven sounds have more content and will be affected more. The Level knob allows you to compensate for this." source


Increase the Order parameter to simulate phasers such as the EHX Small stone and Mu-tron Bi-Phase.

Feedback Tap

"There is no feedback on a Script 90." source

LFO Bypass Reset

If LFO Bypass Reset is set to anything other than Off, LFO will be reset to the selected phase whenever the block is bypassed. This allows synchronizing the sweep to the engagement of the effect.

Start Frequency

"Another fun phaser trick is to set DEPTH to 0 and assign the Frequency Start to an expression pedal." source