Unsound,
I think speakers are generally voiced to sound a particular way with certain kinds of amps and vice versa. I suspect tweaking the impedance load in any given case would change the sound and present a better opportunity for the right amp to now deliver better sound. I doubt that in practice though this would always necessarily be the end result. Its all about amp/speaker synergy which can be achieved via many combos, warts and all. Providing a technically better playing field as a higher impedance likely does does not necessarily assure better results.
I think speakers are generally voiced to sound a particular way with certain kinds of amps and vice versa. I suspect tweaking the impedance load in any given case would change the sound and present a better opportunity for the right amp to now deliver better sound. I doubt that in practice though this would always necessarily be the end result. Its all about amp/speaker synergy which can be achieved via many combos, warts and all. Providing a technically better playing field as a higher impedance likely does does not necessarily assure better results.