For another opinion read here:
http://www.martinloganowners.com/forum/showthread.php?15238-Speaker-jumper-cables-diagonal-wiring-worth-trying&highlight=jumpers
(my comments are included in the attached link)
http://www.martinloganowners.com/forum/showthread.php?15238-Speaker-jumper-cables-diagonal-wiring-worth-trying&highlight=jumpers
(my comments are included in the attached link)