Always consult the Owners Manuals first

Comparing the Axe-Fx II, AX8 and FX8

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Axe-Fx XL Plus front.png

AX8.jpg   FX8-mk2-top.jpg  

List of blocks per device

Comparing the available effects in each device

Axe-Fx III versus Axe-Fx II XL+

”Everything sounds better. I think a big part of it is the quality of the I/O. The I/O measures flatter and less distortion than my $2000 interface.” source
"It actually does sound a little better. The extra DSP horsepower means that we didn't have to make compromises in some of the algorithms. The amp modeling algorithm is very similar but there's a few places on the II where we had to make compromises to get the algorithm to run within the allotted time. Also the III has a higher internal oversampling rate and a higher bit depth on some calculations (64-bit vs. 40-bit)." source
"Better algorithms, higher upsampling, better analog I/O design."

Comparing aliasing performance

Axe-Fx II XL+ versus AX8


Axe-Fx II XL+ – provides effects in a 4x12 grid, including Quantum amp/cab modeling, and extensive routing options in a 19" rack device. It features multiple outputs, an effects loop and various digital I/O. The MFC-101 foot controller is connected through FASLINK. It has all Fractal Audio effect algorithms and supports Tone Matching and IR Capture.

AX8 – all-in-one floor version of the Axe-Fx II, designed for the gigging musician. It provides Quantum amp modeling and UltraRes speaker cab sims, plus hundreds of effects and the familiar 4x12 grid, with the same quality as the Axe-Fx II. It differs from the Axe-Fx in that it offers only one instance per preset of amp, cab, and some effects blocks (e.g. Reverb, Flanger, etc.). Also, certain esoteric effects found on the Axe-Fx are not included in the AX8 (Vocoder, Megatap, etc.) It has multiple outputs offering Humbuster technology, S/PDIF out, and an effects loop.

The differences are discussed in the AX8 Owner's Manual



  • Axe-FX II: two TigerSHARC DSPs.
  • AX8: two dual-core 450 MHz ADSP-21469s DSPs and two microcontrollers.
  • The devices use the same converters and op-amps.


  • Axe-Fx II: 19" rack device.
  • AX8: floor device.

Expression pedals and switches:

  • Axe-Fx II XL+: two PEDAL inputs.
  • AX8: four connections for expression pedals and switches.

Analog I/O:

Digital I/O:

  • Axe-Fx II: USB audio, S/PDIF, AES.
  • AX8: only S/PDIF out.

Hardware interface:

  • Axe-Fx II: for remote switching you need a separate foot controller such as the MFC-101. No dedicated physical amp controls (menu only).
  • AX8: 8 numbered assignable switches and 3 assignable F-switches. More information. Dedicated physical amp controls on top of the unit with LED-rings.


  • Axe-Fx II: headphones output.
  • AX8: no headphones output.


  • Axe-Fx II XL+: hardware-separated MIDI IN, OUT and THRU connections. MIDI can be used for editing.
  • AX8: MIDI IN and shared MIDI OUT/THRU connections. MIDI can't be used for editing.


  • Axe-Fx II: no USB host, needs driver on computer for editing and data transfers.
  • AX8: USB host, no driver needed.

Effects and parameters

Axe-Fx II:

  • Full set of all effect algorithms. Many of the effects are available in more than one instance (two Amp blocks etc.). Compared to the AX8 (and FX8), there are a few differences in X/Y switching.
  • Global Blocks.
  • Adjustable Input Impedance.
  • Tremolo in the Amp block.
  • Room ambience, De-Phase, mic modeling, Motor Drive and channel strip modeling in the Cab block.
  • Tone Matching.
  • IR Capture.


  • Selection of the effect algorithms (listed here.) Compared to the Axe-Fx II there are a few differences in blocks supporting X/Y switching. There is one instance available of each effect, for example a single Compressor block, Amp, Cab, Pitch etc, with some exceptions. All "types" within a specific effect (all amp models, all compressor types etc.) are included.
  • Less CPU power. It'll disable blocks automatically when the CPU usage (preset size) gets too high.
  • MORE Looper time than the Axe-Fx II.
  • No Global Blocks, no adjustable Input Impedance, no Tremolo in the Amp block, no Room ambience / De-Phase / mic modeling / Motoro Drive / channel strip modeling in the Cab block, no Tone Matching, no IR Capture.

User interface

Axe-Fx II:

  • Boots to the RECALL screen.
  • Press LAYOUT to see the grid.
  • There are four NAV buttons, PAGE buttons, ENTER and EXIT and a dedicated VALUE knob to navigate.
  • Dedicated X/Y buttons.


  • Boots to the FS (Footswitch) Page.
  • Instead of a LAYOUT button, the grid is accessed as the second page of the main menu. When on the grid, press EXIT to return to the Footswitch page.
  • Instead of NAV buttons, you will primarily use the E/NAV knob to get around menu pages. Instead of a VALUE knob you’ll use A,B,C,D, and E knobs.
  • Instead of dedicated X/Y buttons, you’ll press and hold a footswitch to toggle X/Y for an effect, or if no footswitch is assigned, select or edit the effect and double-tap EDIT.

Editing shortcuts are different because of the hardware design.

Grid, presets and scenes

The AX8 and Axe-Fx II both support the 4x12 grid and scene switching. The AX8 lets you specify the default scene which is loaded after switching presets.

The Axe-Fx II and AX8 cannot share presets. But you can transfer individual block settings from one product to another using the software editors. It's also possible to convert presets with 3rd-party software: FracTool.

The AX8 doesn't provide the Mixer block and Feedback Send/Return blocks.

When using the FXL block to create an AUX output, the FXL block must be placed in parallel rather than series. (Unlike the Axe-Fx II, the AX8 does not detect when a plug has been inserted into INPUT 2.)

AX8 versus FX8


FX8 – provides effects for the gigging musician who uses his own amp(s) and cabinet(s), including specific "no tone suck" support for 4CM (Four Cable Method). It provides dedicated relays for amp channel switching and other amp functions.

AX8 – provides effects, including amp/cab modeling, for the gigging musician who doesn't use a traditional amplifier. It has multiple outputs, S/PDIF out and an effects loop.

  • The interfaces (knobs and buttons, I/O, preset layout) are different which makes operation and navigation different. The AX8 provides physical amp controls.
  • The AX8 uses a 4x12 layout grid, the FX8 doesn't. This means that series or parallel routing of effects is also different.
  • The AX8 uses a flexible architecture that does NOT designate separate PRE and POST chains. It is still possible to use a 4CM hookup, but this needs to be set up manually in each preset using the FX Loop block to insert the preamp.
  • Unlike the FX8, the AX8 is NOT specifically designed for unity gain, but when you’re using it “direct” this really should not be a concern.
  • The effects in both devices mostly the same with a few differences. See Effects list.
  • The AX8 has no RELAYS to switch other gear. Instead, it has four jacks for external switches or pedals.
  • The AX8 has a S/PDIF digital output.
  • The FX8 has a global looper. The AX8 Looper is not “global”, meaning it needs to be inserted as a block on the grid for every preset where you want to use the Looper.
  • The FX8 and AX8 cannot share presets, but you can transfer individual block settings from one product to another using Fracta'l Audio's editors.
  • The numbering of switches on the AX8 and original FX8 is different. The layout of the switches on the FX8 Mk II is the same as on the AX8.
  • The FX8 has additional MIDI blocks. The AX8 has additional Control Switch blocks.
  • The FX8 supports True Bypass, the AX8 does not.

AX8 and FX8 working together

"FX8 works very well in the FX LOOP of the AX8." source

Fractal's comments on the differences between the AX8 and FX8

"The AX8 is not "way more powerful" than the FX-8. The AX8 has one additional DSP that is DEDICATED to amp modeling. If you don't use the amp modeling the AX8 has the same power as the FX-8. The AX8 will not work as well as the FX-8 in 4CM. It is not designed for that. It will do 4CM, as will most digital processors but the FX-8 is the only processor of which I'm aware that is truly optimized for 4CM. That optimization requires a lot of expensive circuitry. The op-amps used are very expensive and there's dozens of them just to support the 4CM stuff. Add to that relays for true bypass, metal film capacitors, etc., etc., and you end up with an expensive design. The FX-8 and AX8 are built on the same code base. There is a single folder that is used to build the common elements for both products. Enhancements to one automatically enhance the other. All this work we've been doing for the AX8 will improve the FX-8. The AX8 will be much more popular than the FX-8. That should be obvious. Most people want the amp modeling. If you don't care about the amp modeling then the FX-8 is the better product and the whole reason for having two different products." source
"The AX8 and FX-8 uses the same converters (CS4272-CZZ) and op-amps. The circuit design in the FX-8 is necessarily much more complex to support true-bypass switching (without pops and clicks) and to optimize the outputs for use in 4CM. The AX8 removes the dedicated true bypass switching circuitry and simplifies the output design to save money. The cost savings is used towards an extra DSP." source
"The XL+ does not offer True Bypass, nor does it offer additional relay outputs for amp channel switching. The FX8 has additional circuitry optimized for 4CM. The True Bypass can be applied to the Pre stage, Post stage, or Both. Giving more flexibility when using 4CM." source