Thanks RonNo, never tested. I am going by theory here.
But, for me, it is one of those things where it seems so intuitively obvious to me that I would not want reflective leather an inch behind my ears, that even if I could not prove the theory with A/B testing I still would be uncomfortable with it and have difficulty relaxing.
I think somewhere on this thread I showed a ray trace diagram that indicated very little reflection from a relatively narrow head rest .. your head does quite a bit of masking of the reflective surface and the seat is often rounded as well as soft so most reflections are away from your ear.
I have done tests myself and with pals and we detected no change of sound with height of back.
I could imagine your perception of the reverberent field may change in an exceptionally precise acoustic space but for most of us
The first reflections of walls, ceilings and floors would completly overwhelm these subtle differences.
As most agree acoustic music in a hall is the ultimate reference it is interesting to note that echograms taken in seating locations in halls show a sea of reflections from surronding seats and shiny noggins all around .. so its familiar territory
In any case I vote for comfort
Cheers
Phil