Wiring – How to figure out the surround sound system left behind by the previous owners

data-wiringhome-theater

I have a basement with what appears to be surround-sound infrastructure. At 4 points in the ceiling (let's call them locations C0…C3), there are a pair of speaker wires. At one location near the floor (call it point F), there are two pairs of speaker wires (probably where the audio controller was located). Nearby there is also a coax cable exiting the wall.

I used a multimeter to test the resistance between the wires at point F and points C0…C3 and each time it reads infinite, suggesting that the wires are not actually connected. However, before I moved in, I definitely noticed that the previous owners had speakers in their ceiling.

I don't know anything about home theatre systems, so what are the possible explanations? Is there some kind of variable-resistance component hiding somewhere in the walls (perhaps some kind of junction that only conducts in the presence of a signal? There are 4 pairs of output wires for only 2 pairs of input wires, after all)? Could they have somehow disconnected the wires upon moving out and, if so, how and why?

Best Answer

If you simply used the ohm meter to check between the wire pair at each of the three terminus points then it is very likely that you would read infinite. The reason being is that the other ends of the pair are laying open someplace else.

To check for the wire routing you would need to check for continuity from one wire at say point C0 to one of the wires at point F.

The two pairs of wires at point F may have been connected to speakers located at or near that point. If that is the case then it is likely that all six of your speaker wires terminate at some location that you have not yet located. Some systems that people install put all the equipment out of site in a closet or adjacent room. This is particularly true for cases where the equipment is almost totally controlled through a user interface on the video screen.

You may have wire pairs looking something like this coming from a closet someplace:

enter image description here

You could investigate trying to trace the wire routing. There are tools that you can purchase that inject a signal into a wire from a battery operated transmitter. Then there is a separate receiver unit with a probe that you slide along the wall. The receiver module will produce a sound that chirps and varies in intensity depending upon how close to the driven wire it is located the probe. I own several of these units and have good to mixed results with them. Here is a link to the unit that I have had reasonable success using.

enter image description here

You can find this unit at better hardware stores, big box locations or online. The price showing at the link above is decidedly better than what I paid for the same unit about 10 years ago.