Axe-Fx III - Constant hiss in monitors and headphones - Solved

jbeattie246

New Member
I have a pair of Mackie HR824 Mk1 studio monitors plugged into OUT 1 via the balanced XLR ports on the back of the Axe-Fx III. When the unit is powered on, I hear a constant hissing noise, the best way to describe it is white noise with most of the low and mid frequencies cut out. I don't see any movement on the III's Meters page.

Noise persists at same volume even when:
  • An empty preset is loaded
  • All physical inputs are unplugged (including USB)
  • All input levels are set at a minimum through the I/O page
  • Using a shorter cable run, 1/4" TRS rather than XLR
  • OUT 1 knob is turned all the way up or down
  • AXE-FX III is plugged into different power sources
  • Using OUT 2 instead of OUT 1
Additional note: Even with nothing plugged into the monitors, there is barely audible noise; however, upon powering on the Axe-Fx, the noise doesn't get any louder until the loading screen goes and switches to the home page (which is an empty preset). I'd also like to mention it is audible with low-impedance headphones - I can hear it through a pair of Apple EarPods, but not through my Sennheiser HD600. I have compared with my Scarlett 4i4 3rd Generation audio interface and there is no noise through the same monitors and headphones.

I am stumped. Is there anything I should try next? This noise drives me crazy because I can't even sit at my desk with the monitors and AXE-FX III powered on without getting ear fatigue.
 
I have a pair of Mackie HR824 Mk1 studio monitors plugged into OUT 1 via the balanced XLR ports on the back of the Axe-Fx III. When the unit is powered on, I hear a constant hissing noise, the best way to describe it is white noise with most of the low and mid frequencies cut out. I don't see any movement on the III's Meters page.

Noise persists at same volume even when:
  • An empty preset is loaded
  • All physical inputs are unplugged (including USB)
  • All input levels are set at a minimum through the I/O page
  • Using a shorter cable run, 1/4" TRS rather than XLR
  • OUT 1 knob is turned all the way up or down
  • AXE-FX III is plugged into different power sources
  • Using OUT 2 instead of OUT 1
Additional note: Even with nothing plugged into the monitors, there is barely audible noise; however, upon powering on the Axe-Fx, the noise doesn't get any louder until the loading screen goes and switches to the home page (which is an empty preset). I'd also like to mention it is audible with low-impedance headphones - I can hear it through a pair of Apple EarPods, but not through my Sennheiser HD600. I have compared with my Scarlett 4i4 3rd Generation audio interface and there is no noise through the same monitors and headphones.

I am stumped. Is there anything I should try next? This noise drives me crazy because I can't even sit at my desk with the monitors and AXE-FX III powered on without getting ear fatigue.
Have you tried to plug your axe into another outlet or room ?
 
Do you have the AFX Out 1 set low or high? I could see a situation where you have the AFX Out 1 set fairly low. Unless you’re attenuating your powered monitors, that could cause hiss because you’re amplifying the noise floor. If that’s your configuration, I’d recommend diming the AFX Out 1 all the way up and rolling back the monitors. If you don’t have an attenuator for that kind of monitor control, there are fairly inexpensive passive balanced line attenuators you could buy. That’s what I use between my UA x8p and Pro Co Switch Witch monitor selector.
 
Do you have the AFX Out 1 set low or high? I could see a situation where you have the AFX Out 1 set fairly low. Unless you’re attenuating your powered monitors, that could cause hiss because you’re amplifying the noise floor. If that’s your configuration, I’d recommend diming the AFX Out 1 all the way up and rolling back the monitors.
Is Output 1 set to -10 or +4? Try -10...
Thank you for the responses, I set the input sensitivity on the backs of my monitors to -10 dB and set the Output 1 level to -10dBV and there is no longer any audible noise. I think the issue was that the monitors were way too sensitive and the AFX's output was too hot which raised the noise floor. Before doing this only 7-8 o'clock on the Out 1 level knob was too loud.
Now I can go back to enjoying firmware version 21 again :)
 
Thank you for the responses, I set the input sensitivity on the backs of my monitors to -10 dB and set the Output 1 level to -10dBV and there is no longer any audible noise. I think the issue was that the monitors were way too sensitive and the AFX's output was too hot which raised the noise floor. Before doing this only 7-8 o'clock on the Out 1 level knob was too loud.
Now I can go back to enjoying firmware version 21 again :)
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I own the same as yours but mk2, I use them for tv, vinyl listening and gaming now 😅. They are super great studio monitors . I have recorded a few albums with them but the problem is that when you mix with them , as they accept a lot of basses, you have surprises in others audio systems.

I have tried them with the axe, they sound great .
But I have another pair of krk , and I don’t know why as they cost way less, I prefer doing music mix with them . Maybe one day I will use them back in my « studio » who knows ☺️
 
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