I wonder is there any way of solving this problem except resoldering the wiring? Or would the issue be audible?
Its not an audible issue. I am not even going to bother myself (probably a few minutes job).
It can be solved in 2 ways:
1: open it up and wire correctly to the connector.
This requires popping out the ring on the back that holds the rear plate (pry open with your nail, be careful NOT to break it) and you can access the connector and wires. Simply swap the wires on the connector. It is easy to see why the driver is wired in counter phase... the wiring is 'logical'
2: Make a custom cable and wire the 2x 3.5mm plugs in reverse (so sleeve on tip and tip on sleeve)
You can then only use that cable on the HE400SE.
personally I am not bothered by it and only notices after I measured it otherwise, like all other HE400SE owners and reviewers would never have known.
It's a non-issue in practice.