Chorus block

The information on this page supplements the official manuals.

Chorus: supported by which Fractal Audio products?

• Axe-Fx II: yes.
• FX8: yes.
• AX8: yes.

X/Y switching in the Chorus block

• The Chorus block in the Axe-Fx II, AX8 and FX8 supports X/Y switching.

Position of the Chorus block

• It's a matter of personal preference where to put the Chorus block: before ("pedal") or after ("rack") the Amp block. When placed before the Amp, make sure the Chorus is set to mono (LFO Phase is 0).

Chorus and phase cancellation

• Some Chorus types (such as 80s and Triangle) invert the wet sound on one side. If you're collapsing the signal to mono, the wet side will cancel (Audio topics#Phase cancellation) and you'll hear no chorus at all.

Number of chorus voices

• Selecting more than 2 voices is useful only when LFO Phase is not zero. source
• Manual: "Whenever the number of voices is set to more than two, the LFO type will be changed automatically to “SINE.” If the number of voices is greater than two and the LFO type is changed to something other than “SINE,” the number of voices will be reset to two."

Vintage Tape chorus type

• This type in the Chorus block uses the tape delay algorithm which is used in the Delay block. This type sums the left and right block inputs into mono, so use caution as stereo cancellation may occur.

Dimension D chorus type

• This type in the Chorus blocks is based on Roland's SDD-320 Dimension D.
• Original Dimension D manual.
• Cliff's comments:
  • "The Dimension Mode parameter turns on "Dimension Processing". This can be turned on in any type. However I highly recommend using the Dimension Type as it sets the correct base algorithm, LFO type, delay time, phase, etc., etc. as well as turning on the Dimension Processing. The Dimension D is really just a typical chorus. At the output, however, some special processing occurs that gives that unique sound. Turning Dimension Mode to one of the three settings engages the various aspects of that processing." source
  • "A Dimension D is a fairly typical chorus with some added analog processing on the outputs. The analog processing has a "normal" mode and a "boost" mode. The unit itself has four switches. These switches set the rate and the depth as well as turn on the boost mode. The switches do the following: Slow rate (0.25 Hz), low depth. Slow rate, normal depth. Fast rate (0.5 Hz), normal depth. Fast rate, normal depth, "boost" on. The depth is actually reduced in modes 3 and 4 to compensate for the higher rate. In the Axe-Fx this is done automatically when Auto Depth is on. Therefore I've indicated the depth as "normal" in modes 3 and 4 as the amount of pitch shift is roughly the same as mode 2. There is also an EQ that is present in all the modes on the dry signal. The LFO is a triangle wave and is 180 degrees out of phase between channels. The Dimension Mode parameter has three settings: Low, Medium and High. Low: Dry EQ off, boost off. Med: Dry EQ on, boost off. High: Dry EQ on, boost on. The Low setting has no equivalent on an actual Dimension D since the dry EQ is always active. The Dimension Type sets the LFO type, phase, Auto Depth, Hi Cut, etc., etc. and sets the Dimension Mode to Medium. With the appropriate settings of Rate and Depth you can duplicate modes 1, 2 & 3 on the actual Dimension D. To duplicate mode 4 you simply set the Dimension Mode to High. The Rates are given above. I've found a Depth of around 25% to be a good starting point. Increase or decrease to taste. The Type does NOT preset the Rate or Depth." source
  • "Dimension 1 is the same as previous firmware and is "digital". Dimension 2 (firmware 17 and later) uses the new BBD algorithm." source

BBD algorithm

• The Chorus block in Axe-Fx II firmware 17 and later (including AX8) has a new algorithm based on the BBD algorithm developed for the Flanger block. All the “Analog” chorus types use this algorithm.

Creating a Vibrato effect with the Chorus block

• There's no dedicated Vibrato effect in the Axe-Fx II and AX8. You can create this efefct by using a 100% wet chorus.
• A classic "VB" pedal vibrato effect typically uses a TRIANGLE waveform for the LFO, but the classic "CE" vibrato uses SQUARE.
• Matt Picone: "A Vibrato effect causes pitch to vary periodically, creating a "warble." This can be created easily on the Axe-Fx using the Chorus block set for mono and the Mix at 100%. Vibrato depth and rate may be set as desired. You may wish to set chorus Auto Depth to "OFF" for more dramatic vibrato effects."
• Forum member Scarr: "The rumour is just the Boss VB-2 was a CE-2 without the dry signal mixed in (and pedal ramp on depth). A switch to disable the dry signal is a popular CE-2 mod."

Various Chorus tips

• Forum member and effects wizard Simeon provides a load of magnificent delay effects, including chorus.
• Javajunkie's recreation of the Boss CE-1 Chorus and Vibrato tones.
• Chorus in Wikipedia.
• Vibrato in Wikipedia.
• Recreating the Tri-Chorus.