Keep in mind the test leads on the DMM are not resistance-free and the DMM itself has a tolerance at different ohm readings, but usually don’t state or promise any tolerances when measuring below 500 ohms. Measurements in the milliohm ranges should be done by more precise instruments or at least a 4-wire Kelvin test (plenty of info on Google how to do that).
Speaker wire impedance? Speaker impedance?
I finally got into the owner’s manual for the speakers I bought last May (Revel M126Be) and under "SPEAKER CABLE" Revel is saying that, "High loop resistances that exceed 0.07 Ohms (for each wire run) will cause the loudspeaker’s filter network to be mis-terminated, resulting in considerable degradation of sound quality."
I ohmed out my (longer than I think is optimal) single run (the Revels are not bi-wireable) of (what I think I remember being) Kimber 8TC and I read 0.07. My B&Ws were shotgun bi-wired, so today I also doubled up my single runs with the other bi-wire cable (so two wires are terminating on one speaker post for + and - for both speakers) and rechecked the impedance and read 0.05 ohms which I assume is a variance going in the proper direction.
But I have a probably stupid and probably very basic question (as I make NO claims of having a tight grasp on this stuff). If a lower impedance run of speaker cable makes for an easier load for an amp to drive, why is it that a speaker with higher impedance is a easier load to drive? Can this be dumbed down for me?
I apologize because I am sure this has been asked before, but I cannot find the right combination of words for a search engine that is yielding an answer.
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@gs5556 , basically you are saying that measurements I took with my meter set to ohms are probably not accurate? |
Impedance and resistance are not the same thing. Resistance is a fixed value, a 10 ohm resistor is a 10 ohm resistance a wire has a resistance value per foot.. Impedance, or conductance, is a value that changes in relation to AC circuit behavior., and since AC is ever changing, it is a measurement based on the Root Mean Square of the voltage. Rough impedance values can be calculated if you have the values of components and RMS V and I. Unless you have sophisticated test equipment, and the correct formulas you will not be able to "measure" impedance. There are basic electronic tutorials on you tube that actually explain the behavior of AC circuits MUCH BETTER than I can... yeah, I was surprised too. |
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