shielded vs. non-shielded in longer runs of cable

I'm in the process of rearranging my listening area so I can get as much equipment out of the middle of the speakers as I possibly can. The plan is to use longer single ended interconnects (ten feet) and locate the amp between the speakers. I've become attracted to the sound of minimally to non shielded interconnects but am concerned that going from one meter to three meter wires will create problems with hum, rfi, etc. I've not had any problems at all with the shorter unshielded length. (Our home is in a suburban environment without any obvious sources of electrical noise pollution.) Do any readers here that used non-shielded interconnects have experience with longer lengths?