Speaker cables are connecting cables between the output of the power amplifiers and the speakers. In order to keep losses in speaker cables as low as possible and to transmit as large a sound volume as possible, high-quality copper or silver strands are used for this purpose. These connect the low impedance speaker output of the power amplifier directly to the speaker.
The speaker cable is of the greatest importance in the audio equipment chain when it comes to signal transmission, because it is the longest cable in this chain and must bring the sound quality and output power delivered by the power amplifier to the speakers with as little loss of sound as possible.
Speaker cables are flexible, unshielded, insulated stranded copper wires with cross sections of 0.75, 1.5, 2.5, 4, 6, and 10 qmm, the latter being designed for PA systems. The conductor resistance is extremely low, skin effects are largely compensated for by the stranded wire. The sheathed cable is often made of transparent polyvinyl chloride( PVC).
Each individual speaker cable and each individual stranded wire forms an inductance in itself, whose characteristic impedance increases with frequency. Since inductances form magnetic fields when current flows, the magnetic fields emanating from each wire influence the other strands and wires. Manufacturers try to reduce this influence by constructive measures. The same applies to capacitive interference.
To prevent mixing up the amplifier and speaker connections, the connections on the amplifiers, the speakers and the speaker cables themselves are color-coded, red (+) and black (-). This ensures that all speakers in all speaker cabinets are working in phase, thus all diaphragms are moving outward or inward at the same time. Speaker cables are terminated with high-quality speaker plugs. Since no uniform standard for speaker plugs has been established, a wide variety of plugs and connection techniques are used: screw terminals, cable lugs, banana plugs, RCA plugs, DIN speaker plugs, Speakon plugs and also the jack plug. To prevent oxidation, the plugs can also be gold-plated.
In terms of the connection concept, a distinction is made between connection with one speaker cable per speaker cabinet, bi-wiring and tri-wiring.