How to wire ceiling speakers where each pair of speakers has only two wires total

Question

I bought a house which has 5 pairs of ceiling speakers (10 speakers total). The panel in the wall has 5 pairs of wires, (10 wires total). This is confusing to me, since I thought each speaker would require two wires for itself. When I try connecting my receiver to the panel, I find that a single pair (red/black) causes sound output in a PAIR of speakers. Does that mean I have to wire the whole house with mono sound? How are two speakers controlled by a single pair of wires? (Is there a splitter internally?)

Update: I connected my home receiver to 3 pairs of speakers in "All Channel Stereo" mode, and things sound pretty good. I still don't understand how this is working though.

Answer 1

You should put a meter on them and check the impedance. You could also pull a pair of speakers to see how they are wired.

Ceiling speakers are not an "audiophile stereo sound" setup, typically - they are designed to cover a large area so you can hear the sound all over the house (or area they cover.)

Two typical (hardly the only) ways you might get what you have are a pair of 4 ohm speakers wired in series to make 8 ohms, or a pair of 16 ohm speakers wired in parallel to make 8 ohms again, since many things like 8 ohms for speakers. At work I have a pair of 8's wired in series to make 16 on a system that is exposed to abuse, in an effort to help the speakers survive the abuse...

Other things you might see (particularly in ceiling speakers) would be a transformer and tap (reconnectable wire) on each speaker intended for a "70 volt" speaker distribution amplifier.