You may or may not experience hum & noise pickup problems from running a long unbalanced interconnect. I've read of others doing so with no problems at all; it depends upon the impedances at source & load in addition to the particular cable in use. The only way to know for sure is to try it. You may be able to borrow some long interconnects (& speaker cables) of your preference from Cable Company (www.fatwyre.com). For this testing, they need not be exactly the length you need permenently (just move some things around if necessary). Incidentally, Cable Co's nominal cable rental fees are applicable to any future purchases of anything that they sell. Theoretically you're better off with shorter speaker cables & longer interconnects, although as always YMMV. I've always been forced to use longer speaker cables due to room-architecture; frankly I don't worry about it & these speaker runs are even a bit longer than yours are. I much prefer a networked speaker cable design for my longer runs, MIT T2, T3 or T4 would be good for your theater application. At that 4 to 5 meter length I wouldn't expect a great deal of difference one way or the other though. You'd have to try it out yourself to find out, but remember that these are only the surrounds anyway so not worth significant expenditure IMO. In any case be sure to use a decent quality cable; if you have only zip cord etc. then definitely do something about that right away.
