I live in an apartment that is wired for surround sound. One of the jacks works, but the other doesnt. I have changed the wire from the receiver to the wall and the wall to the speaker, tried different speakers and I also pluged the speaker into the wire that goes from the receiver to the wall into the speaker to see if i had it connected properly to the receiver and it worked. so this leads me to beleive there is a problem with the wiring in the walls. the apartment said it was on my end. how can i test to see if the wire inside the wall is carrying the signal besides what I have already done?