Tuner

Available on which products

• Axe-Fx III, FM9, FM3: yes
• Axe-Fx II, AX8, FX8: yes

Tuner types

Needle and strobe tuner

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[1] The strobe tuner and bar tuner use different algorithms. The bar tuner measures the average period of the waveform. The strobe tuner works like, well, a strobe tuner. It "demodulates" the signal with a quadrature oscillator. This effectively measures the fundamental ONLY. The frequency of the fundamental will not necessarily match that of the overall waveform.

So it's like having two tuners, a traditional tuner and a strobe tuner running simultaneously and, just as with separate physical tuners, the results may not necessarily be the same.

A guitar string is not perfect. The resonances of the overtones aren't always perfect integer multiples of the fundamental. This is exacerbated by the pickups which pull on the strings and cause the overtones to be off (in extreme cases causing the dreaded "stratitis").

Which measurement is correct? That's up to you decide. Some people prefer the sound of the strings being tuned to the frequency of the overall waveform. Others prefer the results of a strobe tuner.

[2] The needle is a correlation tuner. The strobe tuner downconverts the signal to baseband and then displays the I/Q vectors as a strobe tuner simulation. Zero-crossing tuners are inaccurate.

If your strings are old the needle tuner will differ from the strobe tuner because the strobe tuner only displays the fundamental. When your strings get old the harmonics become out-of-tune with the fundamental.

[3] The needle tuner is not designed to tune that high. It's designed to tune open strings. Use the strobe tuner for intonation.

[4] The tuner was optimized for open strings. It was never intended for use as an intonation tool. For that you should always use a high-quality, dedicated strobe tuner.

[5] The strobe tuner in the Axe-Fx uses a different algorithm and is limited only by the accuracy of the crystal oscillator. So even if 0.6 cents is somehow not accurate enough you can use the strobe tuner.

Mini tuners

The Axe-Fx III, FM9 and FM3 also display mini-tuners at several places.

Parameters

Flats and sharps

The Display Mode parameter lets you switch between displaying all flats, all sharps or a mixture of sharps/flats for the displayed note name.

Tuner source

Axe-Fx III, FM9, FM3 

Let you choose the input to which the Tuner listens and you can also select all inputs.

Axe-Fx II 

Detects signals at the front input of the Axe-Fx II, at Input 1 at the rear and in the SPDIF signal. This cannot be changed. If Input 1 Mode is set to Left Only in the I/O menu, the Tuner picks up the source signal at the rear left input only. If it is set to Sum L+R, the Tuner picks up the source signal at the left and right rear input.

AX8 

Detects signals at the front input.

FX8 

Detects signals at the PRE input. You can change the Global Detector to POST input, which you'll want to do when using the FX8 in a POST-only setup.

Muted tuning

The signal can be muted when the Tuner is engaged.

You can choose between muting the input or output. Muting the input allows delay and reverb trails to ring out when engaging the Tuner.

Firmware 24.04 for the Axe-Fx III:

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Changed Tuner mute logic so that only selected source is muted when Mute is set to INPUT.

Display the Tuner on heel down

The Axe-Fx III, FM9 and FM3 can automatically display the tuner when an expression pedal is at the heel down position, i.e. the value is less than 5%. The best use is to combine this with the pedal as a volume pedal, because, when you set your expression pedal to the heel down position, the tuner will automatically display.

Tuning

How to tune

Use the neck pickup, hit the string with your thump, turn down Tone. This will decrease the impact of transients and harmonics.

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[6] With any tuner the rule of thumb is to use the neck pickup. The "fullest volume" is not necessary.

Downtuned guitars

The Downtune parameter allows simplified tuning when tuning down one to four semitones. The display will read the natural name of the note, i.e. if tuning down one semitone an Eb will read E. In addition any blocks that utilize pitch information will also be transposed accordingly.

Sweetened tuning

Use the offsets below in the Tuner configuration for Peterson GTR Sweetened tuning, from the Gear Page's Strobostomp users: Do you tune your Guitar in EQU mode or GTR sweetened tuning ? discussion:

Note	Cent offset
E1	-2.3
B2	-2.1
G3	-0.4
D4	0
A5	0
E6	-2.3

Remote control

FC-6 and FC-12 foot controllers

Fractal Audio's FC-6 and FC-12 foot controllers provide a dedicated Tuner action and screen.

Footswitch

Scroll to the Tuner CC in the I/O menu and hit Enter. Click the switch on the footswitch that you want to assign the Tuner to. Or configure it manually by assigning the Tuner MIDI CC to a switch on a MIDI controller. An external switch can also engage the Tuner.

MIDI CC

The default MIDI CC for the Tuner is 15 on the Axe-Fx II, AX8 and FX8. Keep it like this to avoid issues.

The Axe-Fx III, FM9 and FM3 let you set the Tuner CC manually in the I/O menu.

3rd-party MIDI controllers

Certain MIDI foot controllers, like the Gordius, RJM and Liquid-Foot, can show a graphical tuner display that syncs with the Fractal Audio device. This requires that you:

1. Enable real-time MIDI SysEx communication on the Axe-Fx II (I/O > MIDI) by setting it to Tuner or All.
2. Use a suitable cable connection which allows full bi-directional MIDI communications.

To work with the Axe-Fx III, FM9 or FM3, these controllers must either implement Fractal Audio's proprietary communications protocol for those devices and act as a client, or use real-time MIDI SysEx communication (PDF).

MFC-101

The MFC-101 MIDI foot controller has a dedicated Tuner command for the Axe-Fx II, when it's running in Axe-Fx Mode.

You can also program the MFC-101 to turn on the Tuner by pressing a preset switch:

1. In Edit > MIDI, set IntCC00 to CC15.
2. In Edit > Preset, scroll to the designated preset and set IntCC01 to On.

Troubleshooting

Flickering Axe-Fx II display

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[7] Display flickering on the tuner is normal. Some do it more than other. It's just the nature of the display. The display uses a ping-pong buffer. One page is updated while the other is displayed. Then the pages are switched. Some flickering can occur during the page switch. The reason it is noticeable more on the tuner is that the display is updated more frequently.

Wrong tuner information when sample rate is not 48kHz

If the device is connected to a DAW which is not set to a 48kHz clock (Sample rate), the tuner settings may be off.

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[8] The Axe-Fx requires a 48 kHz clock. Anything else will screw up the calculations.

Tuner won't appear or Waiting for tuner... message

If the tuner won't appear after pressing the Tuner switch, verify that the Tuner menu is set to display the first tab page.

Also, for third-party MIDI controllers, SEND REALTIME SYSEX must be enabled in the I/O menu, and the Axe-Fx II, AX8 or FX8 MIDI CC must be set to its default.