I visit my father's house a few times each year. When he built the place, he had it wired for sound using in-wall systems, but (it seems) not by professionals. He blew out a receiver/amp, so I asked him to examine the wiring and he says it has all 8 speakers in parallel, patched together down in the basement!
(See this question for the way it should have been done)
I would like to use my multimeter to find the impedance of his setup next time I visit him. I don't need to be super-accurate so I would like to avoid sine-wave generators and speaker disassembly.
My plan is to introduce a resistor in series (maybe 200W and 1-4Ω) sufficient to make the system safe against accidental volume knob twists. Sound quality and max volume are not terribly important in his case.
If I simply hook my multimeter -- a low-end Fluke -- up to the (single) speaker wire coming from the wall, and then use it to test resistance, am I likely to get a reasonable estimate of the total speaker impedance seen by the amplifier?
Edit: To be clear, the impedance of each of the individual in-wall speakers is presently unknown and would be tricky to obtain (they are actually mounted in the ceilings).
Outcome: Following the advice from Dwayne Reid I purchased a resistor (20W, just to be sure). I found a free tone-generator program for my laptop, and played a couple different frequencies through the system. It took quite a bit of wattage and volume to get near 1V (my father went to find his earplugs), but I got close enough that I felt measurements were OK. Based on that, I obtained 8-9 Ohms of impedance in the system, so the installers apparently had done the job properly!