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.
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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While on the subject of speaker cables.... Do not neatly coil excess speaker (or interconnects) wire, this is, in effect, making a coil, AKA "choke", and will definitely affect impedance. If you have excess wire it is better to have that extra wire "chaotic" crossing it self at close to right angles. Recent research is showing the life on the air side of the insulated wire is as interesting as what takes place in the "conductor". Cheers, pup it's an amazing place there in the Quantum Realm. Visit often. Take only pictures. Leave only footprints.......if you can |
basically you are saying that measurements I took with my meter set to ohms are probably not accurate? @immatthewj Yes. You need a really special Ohmmeter to read the actual resistance of most speaker cables! You were far more likely reading the contact resistance of your probes and probe wires than you were the speaker cables. To read a speaker cable you need an Ohmmeter that can read differences in resistance of only 0.0001 Ohms. That's an expensive and specialized Ohmmeter that can do that! |
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