MEMO: To All Bryston Customers
SUBJECT: Speaker Cable – Rather Than Size – Length Matters
June 2020
What’s an Example of a Good Speaker Cable?
The Amplifier/Speaker interface is a ‘low impedance’ connection. Therefore, in a speaker cable you are looking for low ‘self inductance’ (because inductance rolls off the top end) as opposed to ‘low capacitance’ required in the RCA or XLR analogue interconnect.
Speaker cable should have very low series resistance, R, and series inductance, L, while shunt capacitance, C, is relatively unimportant in this low impedance, high current application. Shielding is almost a non-issue in speaker cables as signal levels are very large and circuit impedances very low.
Speaker cables, however, should be kept as short as possible to minimize power losses and the associated dynamic compression of the music signal.
Going from say 4 feet to 8 feet is a non-issue under most circumstances especially with adequate gauge wire.
Individually insulated wires should have a diameter less than AWG #18. That means that the AWG number for all individually insulated wires must be higher than 18. However, in order to keep cable resistance very low, the cable will have to be made up of many of these individual wires connected in parallel. Also they must be woven in a manner that keeps inductance low.
If a choice must be made as to which of your cables should be made longer, always let the additional length be taken up with your interconnect cables.
We haven’t forgotten about the shunt conductance, G, of the speaker cable. This primary constant represents the conduction or leakage current between a cable’s conductors through a less than perfect dielectric material. As such, shunt conductance, G, is a bad thing as it contributes to signal loss. Fortunately, in any cable worth its salt, it is extremely small and can be ignored in most cases.
