Always consult the official Owners Manuals first


From Fractal Audio Wiki
Jump to navigation Jump to search

Available on which products

  • Axe-Fx III, FM3, FM9: yes
  • Axe-Fx II, MFC-101, AX8, FX8: no

About channels

Most of the effect blocks in current firmware have 4 channels. Channels can be regarded as mini-presets in each block. Each channel provides a unique set of parameter values. Switching between channels is instantaneous and pretty seamless and can be done manually (on the hardware or with a foot controller) or automatically when changing scenes. Channels can also be switched via MIDI for applications requiring automation.

Channels provide quick and easy switching between sounds without the unwanted side-effects of preset changes (due to grid reordering). For example, set the Amp block so that Channel A is a DELUXE VERB model, Channel B is a PLEXI, Channel C is a RECTO and Channel D is FAS MODERN. Then, change channels (sounds) almost instantly at the touch of a button.

Channel-switching is the successor of X/Y switching, a feature of the Axe-Fx II, AX8, FX8 and MFC-101.

The differences between presets, scenes and channels can described in another way:

A preset is like your entire traditional pedalboar.
Scenes are like your entire traditional pedalboard at a particular moment, with effects set on or off and channels set to a specific sounds.
Channels are like a pedal on that pedalboard with its controls set in a specific way. There are four channels in most blocks, so there are four different sets of settings.

See the Owner's manuals for more information.


[1] Channels are the cat's sphincter. Many blocks, including the amp block, have four channels. Channels switch instantly.

[2] Channels save all settings for a block. A channel is like a preset within a block.

[3] To recap:

  • Channels can be thought of as a preset for an individual block. For example, you can think of the Delay block as being a stand-alone delay pedal (or rackmount processor) with four presets.
  • Scenes store the bypass state and channel for each block.

By using scenes and channels you can use a single preset for an entire song, an entire set or even the entire show. Since the routing doesn't need to change things switch fast and smooth. When switching presets the processor has to assume the routing might have changed and therefore has to clear all the buffers, mute the audio, etc. which takes time and interrupts the audio.

[4] The Axe-Fx III was designed so that single preset can be thought of as an entire rack full of processors. Each virtual processor has up to four presets. So if you were trying to do spillover in a rack you would use two reverb processors.

Which effect blocks have channels

The effect blocks on the FM3 and FM9 have the same number of channels as on the Axe-Fx III.

There's a single exception: the Multiplexer has 6 channels on the Axe-Fx III and FM9, and 4 channels on the FM3.

The Controllers block also has 4 channels. [5]

Read this:

How to switch between channels

To switch between the channels of an effect block, use:

  • the hardware GUI
  • the software editor
  • presets
  • scenes
  • FC-6 or FC-12 controller
  • MIDI: assign a MIDI CC in the MIDI/Remote menu (Axe-Fx III, FM3, FM9 only), and specify a value to select a specific channel, where:
0 = A
1 = B
2 = C
3 = D

Gapless changes

Prior to firmware 23 for the Axe-Fx III (and corresponding FM3 and FM9 firmware), switching channels on an Amp block and some other effect blocks would cause a short gap in the sound. There's none now, depending on the global parameter Gapless Changes.

Even with the global parameter disabled, channel switching speed has been improved in firmware 23 and later (and corresponding FM3 and FM9 firmware), in particular Amp and Cabinet block channel switching times.

Also read:


[6] There are caveats:

  1. If presets are using a lot of CPU then the gapless switching may not work as there is not enough CPU available.
  2. If presets are "stale" (saved under an older revision) then gapless switching may not work until the presets are saved. This is because the preset is being updated during the switchover.
  3. If you switch presets rapidly you may get a gap because a lot of stuff goes on in the background after switching presets to get ready for the next preset change. If you switch before these background tasks are completed then you'll get a gap. It can take a few seconds for the tasks to complete.

Channels and CPU usage

CPU usage is calculated based on the currently selected channel of an effect. When switching channels, CPU usage may change.

Channels and Scene Ignore

The Scene Ignore parameter makes sure that the current block channel is carried over to the next scene. Read this: Scene Ignore

Channels and modifiers

If an internal or external controller is assigned as a source to a parameter, you can choose between applying it to all channels of that block, or to just a single channel. Read this: Controllers and modifiers

Note that a parameter allows only one modifier, not multiple.

Copy or swap channels

On the hardware, channel settings can be copied-and-pasted within the same block (Layout > Tools), or swapped.

To copy channels between blocks and to/from other presets, use the software editor.

Reset a single channel or all channels

Resetting a block defaults the parameters of the current channel. It does not change the settings of other channels.

To reset all channels of the block, switch to the other channels and repeat the process, or use the software editor to reset the entire block in one go.

Read Reset a block for more information.

Tips, tricks and troubleshooting

Use channels to compare sounds and settings

Channels offer an easy way to compare sounds when tweaking. They also allow you to quickly detect non-default settings by resetting one channel to default settings and then comparing the channels.