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Hardware FAQ

Can ASTi provide advice and recommendations for speaker cables, and do you have any specific “dos” and “don'ts” related to speaker cables?

Let's address the latter part of this question first.

One “don't” that we at ASTi hold close is this: Don't be mislead by the many “snake oil and smoke and mirrors” cable vendors that seem to imbue speaker cables with magical (and astronomically expensive) properties. No matter what Monster Cable, Audioquest, or Cardas claim (or any other esoteric speaker wire manufacturer for that matter), there has never been any proof in any unbiased listen test that there is any benefit from using these “snake oil and smoke and mirrors” inventions.

The most amusing claim is that some speaker wires are directional…yes, some manufacturers have decided that their cables must be installed in a particular orientation (usually indicated by an arrow printed on the outer jacket of the cable indicating the wire's “designed” direction from the amp to the speaker). All sorts of claims are made trying to justify this. However speakers are inherently A/C (Alternating Current) devices, and hence the electrons in a speaker wire spend just as much time traveling in one direction, as they do the other, so there is no fathomable reasoning that explains just how a speaker cable can possibly be directional, well except possibly being able to charge 10 times more to cover the cost of printing the arrows. In fact if you consider this claim further, the more you realize the “wacko” aspect to this – if the cable truly did work better in one direction versus the other, then the resultant sound cannot possibly be anything other than distorted when the electrons are flowing in the reverse direction!

Another odd claim heard for some of the astoundingly expensive speaker connects on the market1 is that 'normal' speaker cables exhibit some resonance in the audio band, due to their claimed transmission line properties (since it is common to model a cable as an RLC network). While the RLC model is not invalid, the (usually unsubstantiated) claim that the resonance occurs in the audio band (most often mentioned is 1.5kHz), is very easily proven through basic electronic math to be hopelessly incorrect, and even for a long 50 foot 10AWG cable of quite humble specification, the resonant frequency calculates out to be 2.02MHz (some 2 magnitudes beyond human hearing)! In reality cables do not resonate at all. The model represented here is a single RLC lumped circuit for simplicity and is only accurate at audio frequencies for circuit analysis. A speaker cable is actually a distributed element and should be represented as an infinite number of lumped RLC models. As an infinite number of lumped RLC circuits are modeled becoming its true distributed form factor, we see the resonance frequency go to infinity.

In summary, don't buy any cable that claims anything other than the simple design goal of connecting an amplifier to a speaker.

So why does this matter?

The bottom line is that the speaker cable DC resistance should present no more than 5 percent of the impedance load presented by the speaker, and hence the only real issue of concern is the resistance of the selected wire per foot. The JBL speakers ASTi most often recommends have a rated impedance of 4 Ohms; hence we do not want to see a DC resistance greater than 0.2 Ohms for the cable run.

In general, the recommended distances run per wire gauge are as follows:

Up to 40 feet 14 AWG
40-60 feet 12 AWG
60-100 feet 10 AWG

Generally ASTi recommends Belden cable for most audio uses, and the following work well for speaker applications:

14 AWG Belden 5100UP
12 AWG Belden 5000UP
10 AWG Balden 5T00UP

Equivalent products from Whirlwind and Canare are equally recommended.

This brings us to the next question. Are there any non-recommended speaker cables that are exceedingly cheap?

As long as the wires obey the wire-gauge rules for the running distance, they should be fine. In fact, 12AWG house mains wire (solid core wire) used to wire most 15 and 20 Amp circuits work great and that is as cheap as you can get. Of course, solid wire is not flexible, so this presents installation issues, but aside from that it works just as well as anything else.

1 A definition of “astoundingly expensive” is Cardas Golden Presence 3.0m (10 foot) speaker cable (pair) for $2,184, a cool $109.20 per foot!