What is the desired ga. for a speaker cable less than ten feet long ? How does a different ga. affect the sound ? Then winding of such ? Litz, Parallel, twisted ??

charles

Hi Charles,

Here is some information I posted on my forum sometime back. It deals with various gauges of wire, DC resistance, inductance and inductive reactance. I updated my post.

There has been a lot of confusion over the years concerning twisted wires and whether that is the best type of speaker wires. One could also consider internal speaker wiring as well. Some are dealing with long speaker wires from one room to another. I used "red" and "black" as the speaker wires.

Frankly, I parallel 18 gauge wires from amplifier to single pair jacks on my test two ways. In my case I found 10 wires per speaker lead sounded best. The larger number of paralleled wires not only increased the total gauge of each lead, thus less DC resistance, but also vastly reduced the inductance of each lead.

Inductance is frequency dependent. For comparison, below is the DC resistance, the straight wire inductance, and inductive reactance for 5 feet of single wire and parallel wires at 20khz:

Single Single Single 10 parallel

18 gauge wire 13 ga. ~9 ga. 18 ga.

.0325 .0104 .0066 .0065 DC resistance

2410 nh 2232 nh 2162 nh 482 nh

.30 ohms .28 ohms .27 ohms .03 ohms Inductive reactance at 20khz

Notice the 10 parallel 18 gauge wires equate to an approximate 9 gauge wire in DC resistance, but the inductive reactance is only 1/10th that of the 9 gauge wire.

(You may have heard the past arguments over the small wire parallel with the large wire improving the highs. The highs were increased because the inductance/inductive reactance of the two wires is about 1/2 that of a single wire.)

Remember, this is for a single 5 foot lead, not both leads. Multiply this by 2 for the total 10 feet speaker lead length. I would say .54 ohms is quite a bit in series with a 4 ohm, or 8 ohm speaker, although the impedance of a speaker at 20khz is higher. One could easily be about half a db down at 20khz, a couple of tenths at 10khz and even a tenth at 5khz. Whether one notices a difference will depend upon some factors. I and friends perceived a difference between 8, 10, and 12 parallel wires per lead. 10 Sounded best.

I used two conductor doorbell wires from ACE hardware. Both wires inside the jacket were connected in parallel. I separated the red speaker lead wires from the black speaker lead wires to minimize the capacitance, to just a few pf.

Concerning twisting speaker wires, to cancel inductance/inductive reactance, here is a post reply I made.

In order to eliminate (wire) inductance, both red and black wires would have to occupy the same space, which they cannot. Insulation thickness between wires also hinders attempts to lower inductance. Twisting is spiralling.

A simple comparison example from: http://www.bdloops.com/twisted_wire_test.html

- 6’ x 12’ Twisted pair loop (7 twists per foot*) with 20’ twisted lead-in, jacketed, 16AWG. 64.1 µH

uH is micro (1 millioneth) 38 feet total length in large loop. My 10 foot 10 conductors of 18 gauge parallel conductor example only has some 964 nano henries (nano = 1 billioneth).

Wrapping them together will create capacitance, as you stated, which we also do not want, especially when higher frequencies involved.

Here is a quote from another post on another forum.

Inductance cancellation of twisted wires will depend upon the wire gauge (distance from center to center, thus lack of inductance cancellation), insulation thickness for sure (again influencing center to center, thus more lack of inductance cancellation), and frequencies involved.

Here is an example of twisted.

Wire size 18 gauge, dia is 1.023 mm

Separation between centers of two wires: 3 mm

Insulation between wires: ~1mm

Inductance: 18 nh/inch, 1080 nh/5 feet, 2160 nh/10 feet

4 mm separation of centers; Inductance is 21 nh/inch, 1260 nh/5 feet, 2520 nh/10 feet

What about the heavy two wire cables, 6, 8, or even 10 mm between centers? 6 mm is 3000 nh (3 uh) for 10 feet, 10 mm is 3624 nh for 10 feet.

However, for 10 parallel wires the inductance is only 964 nh for 10 feet.

It is actually a little more complicated but you get the gist.

It is advantageous to parallel 4 or more wires vs twisting/braiding for both less inductance and less capacitance. I would say 3 minimum parallel wires basically equals inductance of twisted braided wires, depending upon gauge of speaker wire twisted.

The main disadvantage is the WAF.

Cheers and hope this helps.

Steve