Why should I taper the cable ends instead of using a thinner cable?

The resistance of the speaker cable is yielded from the specific resistance of the conductive material (the copper wire strands) as well as the cable length. As a speaker is connected to the amplifier with two cable connections, and these are in series, the resistance must be considered two times.

This yields the following equation:

Resistance of cable = 2 x the specific resistance (approx. 0.02 ohm mm^2 m^-1) x the cable length in m / the cable cross-section in mm^2

As the individual strands in our cable are not insulated amongst each other, the full cross-section of the cable is available between the ends.

A "bottleneck effect" only occurs at the ends of the cable.

The transition between the cable and any connector (push terminal, soldered connection or pole clamp) is always accompanied by a greater resistance: the transfer resistance.

Compared with the resistance of the entire cable, this transfer resistance, if conducted well, can be disregarded.

Example:

We will consider a cable length of 15 m.
According to the above-given equation, the following values are yielded for the cable resistance.

4 mm^2 – speaker cable with tapered cable ends (2 cm)

0.15 Ohm

2.5 mm^2 – speaker cable without tapered cable ends

0.24 Ohm

This yields considerably less resistance if the cable strands are tapered for connection rather than if generally using a thinner cable.

If you would like to calculate your cable resistance yourself, then please use the following equation:

0.02 x 2 x cable length / cable cross-section