Tuner issues - tuners disagree from each other

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jbjhjm

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Hey everybody,

in my band we're currently suffering from tuning deviations.
I started to investigate what happens and right now I'm kinda stuck cause I have no idea what's going on.

I compared single strings (of same instrument) tuned according to
  • My setup (Axe Fx III mk2)
  • Other guitarists setup (FM3)
  • a TC Polytune 3

I verified that for both axe tuners, no micro offsets are enabled and both are calibrated to 440 Hz.
I am confident my picking is causing max ~2 cents of deviation.
(We use drop D tuning so I'll name tone/string "low D" below)

I tune the low D according to the FM3 until it reports to be within +-1cent range.
Then I plug into my own setup and the III reports that low D is tuned around 10 cents too low.
I tune according to my III then.
Both FM3 and the Polytune will now report it is tuned too high ~10 cents.
Comparison by ear, to a guitar tuned according to the FM3, is clearly dissonant.
FM3 and Polytune seem to tune identically, so I think it is my III which is off.
:flushed:⁉️

what could cause such behavior? Did anyone experience similar tuning problems?
On higher strings, the problem exists too, but deviation seems a bit less extreme (but still too much), in range of 5-8 cents.
As a temporary fix, I offset my tuner to 438.5 Hz and the overall tonality between instruments improved.
But that's no true solution.
I'm happy for any ideas, assumptions or speculation of what could cause this.
 
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At least over here my Turbo Tuner ST-300 and Axe-Fx 3 strobe tuner behave pretty much the same, the Turbo is maybe a bit faster responding but that's all.

No idea what could cause that big a discrepancy between Polytune/FM3 vs Axe-Fx 3. Are all of these setups just guitar -> device doing tuning or is there something else in between? Does turning the guitar tone pot down to zero and using the neck pickup improve the situation in any way?
 
Just for testing purposes I've used a keyboard and checked different tuners and have found some pretty surprising variances. I have a preset loaded with a synth block which would be a solid tone for checking tuners. Strings are hard to get a solid tone. Just a thought....
 
FWIW, I'm on the FM9 but noticed this the other day while tuning up with a Boss TU-12. My tuning was quite a bit flat on the FM9. I honestly thought it was operator error at the time. But now that I'm reading through this thread, I need to verify later. I'll check it with my TU-2 and TU-3 also.
 
There are only two possibilities:
1. The on-board clock oscillator is out of spec. Highly unlikely.
2. The unit is using an external clock source that is the wrong frequency.
 
Thanks for all your comments, pretty interesting to hear the other stories.

Clock: Both devices are controlled by built in clock, no digital connections.
Input path: Both setups are using a Stageclix V4 wireless system.

My guitar's onboard electronics are stripped down to just one PU + volume control, so I wont be able to test different settings here.

Summing up the ideas found in the thread, I'll check this out on next "debug session":

  • Reproduce on a guitar with neck PU and highs cut
  • eliminate wireless transmitter, just directly into the device
  • verify general tuner accuracy by feeding it a 440 hz sine wave
  • check accuracy of Drop D vs standard E
 
fractalz said:
Feed the oscillator back to the input and see if it is in tune?
Click to expand...
If frequency detection is off, oscillator may be off as well coming from the same device?! .. better check using an external oscillator, keyboard, DAW vst instrument / tone generator or similar
 
jbjhjm said:
If frequency detection is off, oscillator may be off as well coming from the same device?! .. better check using an external oscillator, keyboard, DAW vst instrument / tone generator or similar
Click to expand...
if the tuner shows that the oscillator is out of tune, there is a bug in the tuner.
 
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