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Comparing the Axe-Fx II, AX8 and FX8

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List of effects per device

Effects list

Axe-Fx III versus Axe-Fx II XL+


Axe-Fx XL Plus front.png

”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 XL Plus front.png



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, SPDIF out, and an effects loop.

The differences are discussed in the AX8 Owner's Manual

"The XL+ front input circuit is identical to the AX-8 except the AX-8 doesn't have the variable impedance circuitry." source
"AX8 and Axe-Fx II share the same code base so any updates to the Axe-Fx II apply to the AX8." source
"Same grid as Axe-Fx II. 512 user cab slots, 512 preset slots. Same factory amps and cabs as Axe-Fx II. Same high-quality, low-noise design as Axe-Fx II XL+. True differential I/O to the converters, not the single-ended stuff used in consumer-grade gear. Silent Switch technology from the MFC-101 Mark III. Humbuster I/Os. Most importantly it has Quantum and the "Fractal Sound". source
"Layout grid is just like the Axe-Fx II." source
"The AX-8 is not an Axe-Fx II on the floor. If it was it would cost a heck of a lot more than it does. It uses the exact same modeling code as the Axe-Fx II. The overwhelming majority of people love the AX-8 and understand its place in the Fractal Audio model line-up. Putting an Axe-Fx II on the floor wasn't feasible due to the DSPs used in the Axe-Fx II requiring active cooling and being very expensive. The AX-8 was designed as a lower cost, simpler product that would address the needs of 99% of users. Power users will want an Axe-Fx II which is still the best modeler in the world." source
"The SHARC processors in the AX-8 support 40-bit word lengths and we use them just as we do in the Axe-Fx II." source
"The AX8 uses the same converters as the Axe-Fx II. We put the money where people can't see it but where they can hear it." source
"The Axe-Fx II can run multiple instances of amps, cabs and most effects. The AX8 cannot. The processors used in the AX8 are not nearly as powerful as the processors used in the Axe-Fx II. They are also significantly less expensive." source
"It does not have the vocoder and several of the other more esoteric effects. It does have the looper, synth and all the bread-and-butter effects. And it has the beautiful high-quality reverb from the Axe-Fx and FX8 (because I'm a reverb junkie). Most importantly, though, it sounds like an Axe-Fx." source
"They are very cool. They're not an Axe-Fx but they're close. Same amp and cab modeling. Stripped down effects section. Two 450 MHz DSPs; one for amp modeling the other for effects/housekeeping. Uses the same silent switch technology as the MFC-101 Mark III and FX8. Switches are assignable per patch via our new "Switch Assign Matrix" feature." source
"It's pretty much "Axe-Fx Lite". All the advanced parameters are available in the amp block, you access them via the traditional edit menu. The dedicated Bass, Mid, etc. knobs can be accessed at any time. And it sounds like an Axe-Fx, so there's that." source
"The AX8 was not designed for use with Global Block." source



  • 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, SPDIF, AES
  • AX8: only SPDIF 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

AX8.jpg FX8-mk2-top.jpg


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, SPDIF 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 SPDIF 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.

Fractal's comments on AX8 and FX8

"FX8 works very well in the FX LOOP of the AX8." source
"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
"Dimensions and weight are the same as the FX8." source
"The AX8 and FX8 uses the same converters (CS4272-CZZ) and op-amps. The circuit design in the FX8 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 AX8 has Humbuster outputs as well. It will do 4CM but probably not as good as an FX8 which was purpose-designed for 4CM. If we used the output topology of the FX8 in the AX8 the AX8 would cost a LOT more." source