Recently purchased AXR4T, connected to the headphones and found that the sound is phase reversal, driver and firmware installed 1.22 and 2.20 have this bug!
Such a serious bug in the past few years no one found?
Well, what you mean with phase reversed? Is one side reversed?
Are both headphone jacks affected?
Yes, the sound on both headphone jacks is 180° out of phase.
Headphone jacks are stereo!
So again, what exactly is phase reversed?
The AXR4T hears vocals in phase inversion.
If one side of the headphone outputs would be phase reversed, it would sound very strange.
Again, what is phase reversed?
If you record vocals, what is the microphone?
Are you sure that the microphone is in phase? Is the phase reverse at the input engaged?
And how do you find out that it is phase reversed, and what is the reference in phase?
And to press the phase reverse button in IBP isn’t an evidence that the outputs are phase reversed.
The vocals I recorded with my apollo and RME soundcard are phase inverted when I listen to them in the AXR4T!
Maybe you can define what you mean with the term phase inverted.
Do you mean by chance that the left channel is coming through the right earpiece?
I only interject because I have seen no other posts describing such a problem. If it existed, many, many complaints would be on the forum, I figure.
I think the term “phase inverted” is pretty clear.
He states that the polarity of the output for one of the two earpieces is inverted. This means if you e.g. playback a (mono) sine on both earpieces, the moment the left side is in the “negative valley” of the sine the right side will be in the “positive valley”.
This results in a very diffuse sound and a noticable reduced base frequency recognition.
@x999x - have you double checked this? Have you tired to play back just a sine (e.g. with the Cubase Tone Generator)? Have you also checked with another audio interface to be sure that this is not an issue with e.g. your headphones?
No it’s not.
Polarity is not phase.
The headphone plug is a three pin TRS plug…
If the wires are connected incorrectly, all signals would be weird. Not only his vocals.
If left and right is switched, you will have switched panning, but no sound differences at all.
If only the vocals are phase inverted, I would like to know how it sounds?
And why is it related to the headphone output?
Yes, but a polarity change results in a phase shift of 180° which is often called phase inversion.
Not sure how to understand his post there. I took the statment that the vocals are phase inverted only as an example and I think he means that all is phase inverted. But that must be answered by him 
I understand it that way that his sound is fine if he plays it back over the “normal” outputs (line, AES3, …) but when listening with headphones he notices that the signal has a 180° phase shift between left and right side.
I just tested with my AXR4U under Windows10 - I cannot hear an unwanted phase inversion on my headphones.
Signal left, signal right, ground…
If the part of left and ground is switched, the other channel will not work at all. Inside the headphones, the ground wire gets split to both capsules.
A real phase shift on one side will affect the panning.
If there is something wrong in the unit with the connection, it is a warranty case. But as already mentioned from others, there is no general software bug, or a general problem with the headphone plugs. It is just this one unit.
Just to make it clear.
I agree that a switch of two wires of a TRS headphone jack cannot create a phase inversion. But it could also be that it is a bug on the digital side (in the firmware or drivers) or even on the PCB.
Or it could be inside his headphones where the two cables are interchanged directly on the moving coil on one side.
If it were a general bug, it would be in your unit as well.
I have RME UFX+ and Apollo x8, I recorded vocals dry with them and played them back on the AXR4T and they sounded phase inverted, then I recorded vocals on the AXR4T and they sounded phase inverted when I listened to them on the AXR4T but when I played them back on other audio interfaces they sounded normal.
I listen to it with AKG k240s and Fostex th900mk2 and both are phase inverted, same result on mac os 13.5.2 and windows 11.
as asked,
The main question is, how do phase inverted vocals sound?
It is not audible if only the vocals are phase inverted.