Oops, removing headphone cable crosstalk might improve imaging but not increase width (aka. separation as seen on the left-right axis, but by improving imaging alone it might improve separation along the depth or radial direction(s)).
I just found this tidbit from aeons ago in the Changstar forum:
(Capacitive crosstalk = internal, due to the amp design, regardless of output connector and cable structure.)
I always thought any crosstalk automatically narrows the stage, but I forgot intentionally inverted crossfeed (aiming for crosstalk cancellation) is used in some DSP effects to widen the stage, and never dreamed that unintentional crosstalk in something as simple as a couple of wires in a headphone cable introduces not only substantial phase shift but phase inversion. 