Ignore the above advice and use the unequal length cables. According to the logic of the above posts the unequal lengths can possibly result in a slight image shift towards the speaker with the shorter cable. If this is true, then it can be easily corrected with the use of a balance control.
Does unequal speaker wire length matter?
My amp is not located centrally between my speakers. Due to the layout of my listening area, the amp is about 10 feet from one speaker, and adjacent to the other - and this will not change. I am currently using two 4-meter cables, but one of them need only be about 1 meter. I am looking to upgrade my cables, could I get away with unequal lengths and save a good bit of money?