Explain speaker cable resistance, capacitacance?


Can anyone please easily explain, without going too technical, the effects on sound of resistance, capacitance, inductance in speaker cable?
For example, these are the specs of two cables made by the same manufacturer:
CABLE 1
Resistance: 0.9 Ohm/100 m.
Capacitance: 17.5 pF/m.
CABLE 2
Resistance: 0.34 Ohm/100 m.
Capacitance: 32.5 pF/m.
What differences should be expected between these all other things (lenght, system) being equal?
Does the same apply to interconnects?
Thank you for your support :)
vmm

Showing 1 response by almarg

The resistances of both cables are low enough to be insignificant for typical lengths. The resistance of cable 1 might become marginally significant if cable length is particularly long AND the speakers have particularly low impedance (I believe that yours don't).

In situations where resistance may become significant, the resulting sonic effects would depend on various characteristics of the particular speaker, including how the speaker's impedance varies with frequency.

Capacitance in a speaker cable is usually unimportant, the possible exception being that if it is EXTREMELY high, some amplifiers may have problems driving it. The capacitances you indicated are very low.

You didn't indicate what the inductances of the cables are, perhaps because they are unspecified. Excessive inductance in a speaker cable can cause a slight rolloff of the extreme upper treble. That will typically be an issue only when cable length is long AND cable inductance per unit length is high (or at least not low) AND the impedance of the speaker drops down to low values at high frequences (that is particularly common with electrostatic speakers; dynamic speakers are more likely to have impedances that rise at high frequencies).
Does the same apply to interconnects?
No. The situation is generally the opposite with interconnects. Resistance and inductance are generally unimportant, because they are insignificant in relation to the input impedance of the destination component, resulting in negligible voltage divider effect. Capacitance may be important, if capacitance per unit length is high AND cable length is long AND the output impedance of the component driving the cable is high. That would result in the combination of cable capacitance and component output impedance forming an RC (Resistance-Capacitance) low pass filter, which can result in a slight upper treble rolloff, and consequent softening of fast transients. That effect will not occur with a speaker cable because of the very low output impedance of the power amplifier.
I read a thread in another forum where they measured cables and came up with one very high end ic that had an impedance of 50ohm, they sounded very surprised with this fact. Why?
Not sure if they meant DC resistance, or impedance at some frequency, or characteristic impedance. 50 ohms would only be surprising if it were DC resistance or impedance at some frequency that is low enough to be within the audible range. Even then it would most likely not have much significance, because it would still be far lower than the destination component's input impedance.

As Rodman and the paper he linked to indicate, there are other less easily explainable effects that can occur, which are controversial in some cases, and in any event can be expected to be system and listener dependent, and to not have a high degree of predictability.

Regards,
-- Al