Speaker cables

There is an ongoing discussion on the necessity of large cross-sections (Querschnitte) for loudspeaker cables. According to an article published in elektor, Nov. 1986, p. 65, two factors are important: cable losses due to resistance and a decrease in damping (Dämpfung). This describes the ability of the amplifier to reduce unwanted movements of the speaker due to resonance and such.

The cable loss can be calculated as P_V=P_L/R_L* R_C.

The cable resistance is proportinal to the cable length and inversely proportional to the cross section.

For a loudspeaker cable of 10 m, the loss (in percent) for three cross sections and four and eight Ohms loudspeakers is:

cable loss 4 Ohms 8 Ohms

0.75 mm² 3.8% 7.5%

4 mm² 0.7% 1.4%

6 mm² 0.5% 1.0%

cable loss	4 Ohms	8 Ohms
0.75 mm²	3.8%	7.5%
4 mm²	0.7%	1.4%
6 mm²	0.5%	1.0%

Bottom line:

If you need long speaker cables, invest the money for larger (2.5 mm² or 4 mm²) cross sections.
If you need just a few meters and little power (for the club night), it does not really matter, but don't go below 0.75 mm².

I have no information (yet), how the damping factor is defined, but in general here the same rule applies: large cross sections and eight ohms speakers are better.

Some more hints:

I prefer round cables to flat ones. They don't get twisted as much.
Use only high quality cables and plugs. Cable problems are sometimes hard to detect and very annoying. The savings would not be worth it.
Yes, there are round 4mm² cables available - try PA and musicians' equipment stores.

written by H. Niemann , last change: 1999-12-23