More Info on Telephone & Audio Cables
Telephone cables developed steadily from the time of Bell’s invention in 1876. The original private lines, stretched between houses, were singular wires of steel or iron, and they suffered markedly from corrosion problems and were inherently noisy. Over time the means to construct a copper steel compound wire was developed which reduced some of the interference noise issues.
Although the superior conducting properties of copper were known early on, it was only later that the technology improved to facilitate the manufacture of a hand drawn copper wire which had a greater tensile strength. This enabled overhead cables to be constructed from copper wire alone, which would otherwise be unable to bear the weight. Such copper wiring with its low resistance and good conductive quality soon became the norm throughout the expanding electrical industry.
These days much of the wire sold as telephone wire in DIY shops will not be twisted pair, but cheaper, low voltage general purpose wire. Twisted pair cable made from copper is the only suitable wire for telephone connections; it conducts voice signal well, and the pairing eliminates much of the electrical interference and unwanted noise for a more reliable connection.
A similar wire is used for speaker cable. Appropriate cable is an essential part of any audio system and an important consideration in your audio hardware for sound quality.
Used as electrical connections between the components of a sound system, the main task of cable wire is to present a low resistance path linking the amplifier to the loud speaker. Less resistance means that it delivers more signal power to the output and hence better sound.
Speaker wire is composed from many copper strands woven together, the number of strands and the wires thickness giving the cable different signal bearing qualities.
Lower resistance is achieved by installing thicker, shorter cables. The shorter the distance the current must travel and the thicker the cross-section of the wire the lower the resistance, which affords greater clarity of signal. To maintain the strength of signal flowing over a longer length of cable a wider gauge is needed, which compensates for the greater resistance.
Telephone and speaker cables are now routinely made from copper for its properties of conductivity and lower resistance, with plastic insulation for protection and to reduce oxidization.