Ian Jackson wrote:

When listening to mono on headphones, I usually prefer to connect the
earpieces in antiphase. When they are in-phase (which is, of course, the
normal condition) the audio image is dead in the centre of your head.
This is very 'unreal', and soon becomes rather tiring. When in
antiphase, the image is spread throughout your head, and is much more
pleasant to listen to. I think that the same reasoning could be applied
to loudspeakers.

Do you have a special pair for mono with one driver reversed or an
adapter plug?

--
Eiron.