Audio Systems: Weak Midrange, internal crossover, series speakers

Question
I own a pair of JBL E90 series speakers and I've recently noticed that my left
speaker sounds a little bit just a little bit lower in midrange than the other
one. This only happens only in some of the songs that I play. Besides, I use a
PS3 as my player which does a better job for me than my regular DVD player.
Now, would help me and guide me if there is a problem with my midrange or
this comes from the certain songs that I listen to? Please provide me with the
solution!

Regards,
Ali

Answer
You must physically switch your speakers. Meaning that whatever channel is driving the left speaker must instead drive the right speaker and vice versa. If speaker with a weaker lower midrange remains on the same channel then it is not a speaker issue. If it moves to the other channel then it is probably the midrange speaker driver or internal crossover.