How To Choose Loudspeaker Cable

Obtain the minimum impedance of your speaker. Some manufacturers like NHT specify it, If you don't know it, use 75% of the rated impedance. For example, NHT says that the minimum impedance of a SuperZero is 7.5 ohms.

Take the desired length of your speaker cable and multiply by 200. For example, if your speaker cable is 20 feet long, then the result would be 4000.

Divide the minimum impedance of your speaker by the number just calculated. In the case of NHT SZ's, we would now have the number 7.5/4000 or 0.001875.

Look on the following table for the proper wire size. Pick a wire whose resistance per foot is less than the number you just calculated:

 

This chart gives a clue about attaching large wires to short terminals - use an inch or so of smaller gauge wire, and solder or otherwise splice it to the large wire. An inch of #22 adds only 0.0016 ohms - about the same as a foot of #12.

The wire sizes you obtain from this procedure are very conservative,  and using wire with up to 2.5 times the resistance (3-4 wire gauge numbers larger)  will usually suffice.

If you have a speaker with impedance that decreases, (rather then the usual increase) with frequency, (Martin-Logan's for example) then some of the highly conductive #8, #10, or #13 center conductor coax that Belden shows on their web site would be recommended because of its low inductance.

If you want to have thin speaker cable for under the rug, then say, 60 (or more) conductor computer ribbon cable with the strands connected into two bundles at each end, soldered to say, some 12 gauge for termination, is an option.

8 Feet Of Monster Cable M2 Speaker wire (Impedance Magnitude, Wire Is Straight) Full Scale is 0.8 ohm

8 Feet Of Monster Cable M2 Speaker wire (Impedance Magnitude, Wire Is Straight) Full Scale is 0.8 ohm

20 Feet Of Home Depot 12 Gauge Wire (Impedance Magnitude, Wire Is Straight) Full Scale is 1 ohm

20 Feet Of Home Depot 12 Gauge Wire (Impedance Magnitude, Wire Is Straight) Full Scale is 1 ohm

20 Feet Of Home Depot 12 Gauge Wire (Impedance Phase, Wire Is Straight)

20 Feet Of Home Depot 12 Gauge Wire (Impedance Phase, Wire Is Straight)

20 Feet Of Home Depot 12 Gauge Wire (Impedance Magnitude, Wire Is In 6" Coil) Full Scale is 1 ohm

20 Feet Of Home Depot 12 Gauge Wire (Impedance Magnitude, Wire Is In 6 Inch Coil) Full Scale is 1 ohm

20 Feet Of Home Depot 12 Gauge Wire (Impedance Phase, Wire Is In 6 Inch Coil)

20 Feet Of Home Depot 12 Gauge Wire (Impedance Phase, Wire Is In 6 Inch Coil)

Output Impedance of Bryston 4BST   (Impedance Magnitude) Full Scale is 1 ohm

Output Impedance of Bryston 4BST   (Impedance Magnitude) Full Scale is 1 ohm

Output Impedance of Bryston 4BST   (Impedance Phase)

Output Impedance of Bryston 4BST   (Impedance Phase)

Input Impedance of KEF Q15  (Impedance Magnitude) Full Scale is 30 ohms

Input Impedance of KEF Q15  (Impedance Magnitude) Full Scale is 30 ohms

Input Impedance of KEF Q15  (Impedance Magnitude) Full Scale is 10 ohms

Input Impedance of KEF Q15  (Impedance Magnitude) Full Scale is 10 ohms

Input Impedance of KEF Q15  (Impedance Phase)

Input Impedance of KEF Q15  (Impedance Phase)

Input Impedance of PCTA/PCABX Loudspeaker Simulator  (Impedance Magnitude)  Full Scale is 30 ohms.

Input Impedance of PCTA/PCABX Loudspeaker Simulator  (Impedance Magnitude)  Full Scale is 30 ohms.

Input Impedance of PCTA/PCABX Loudspeaker Simulator  (Impedance Magnitude)  Full Scale is 10 ohms.

Input Impedance of PCTA/PCABX Loudspeaker Simulator  (Impedance Magnitude)  Full Scale is 10 ohms.

Input Impedance of PCTA/PCABX Loudspeaker Simulator  (Impedance Phase)

Input Impedance of PCTA/PCABX Loudspeaker Simulator  (Impedance Phase)