Speaker Cable

Reels for installation

Most of our speaker cable comes on the reel, for wiring ceiling speakers, running cable round a room or fitting out a venue. Figure 8 cable has its two cores side by side, joined along their length, so it lies flat against a skirting board and splits easily at the ends. Transparent cable shows the copper through the sheath, a common choice for hi-fi, with one core marked so you can keep the polarity straight. Figure 8 is also the easiest to split for the last few centimetres at each terminal, and twin-core cable with a round outer sheath suits runs through walls and ceilings, where the extra jacket protects the cores as they are pulled through.

A full reel costs far less per metre than cut lengths, and it leaves spare cable for the next room or a later change to the system.

Choosing a conductor size

The thicker the conductor, the less of the amplifier's power is lost along the way. Size is given as a cross-section in square millimetres, or as a count of fine strands in each core. A short run to a pair of bookshelf speakers needs far less copper than a long run to a hall full of PA speakers, and lower impedance speakers draw more current, so they benefit from heavier cable.

As a rule of thumb, step up a size for longer runs and for 4 ohm speakers. Each product page gives the conductor size and strand count from the manufacturer. When in doubt, choose the heavier cable: the cost difference over a room is small, and it leaves room for bigger speakers later.

Polarity and marking

A speaker has a positive and a negative terminal, and both speakers in a pair must be wired the same way round. If one is reversed, the bass thins out and the stereo picture loses its centre. Our cables mark one core, with a stripe, a ridge or a coloured sheath, so the marked core can go to positive at both ends.

Decide on your convention before you start, and keep to it for every speaker in the system. Many amplifiers and speakers colour their terminals red for positive and black for negative, which makes the marked core easy to place. If a system sounds thin, with little bass, check the polarity at each speaker first; a reversed pair is the most common wiring slip.

Terminated leads for PA speakers

Professional speakers and amplifiers often use a locking speaker plug rather than bare wire, and our terminated leads come with those plugs fitted at both ends, or with a speaker plug at one end and a 6.3mm jack at the other. They are ready to connect a PA amplifier to its speakers in seconds, and the locking plug holds firm when a lead is kicked on stage.

Never use an instrument lead to connect a speaker. An instrument lead is built for a small signal, not for speaker power; a speaker lead has the heavier cores the job needs. Choose a lead that reaches from the amplifier to the speaker stand with a little slack, and keep a spare in the case.

Running cable neatly

Plan the route before you cut. Run cable along skirting boards, under carpets on flat runs or through ceiling voids, and fix it with cable clips at regular intervals so it does not sag or snag. Leave a little slack at each speaker so it can be moved without pulling on the terminals, and label both ends of every run in a larger system.

Keep speaker cable apart from mains cable where you can, and cross them at right angles where they have to meet. Leave a small loop at each ceiling speaker so it can be lowered later without a new run of cable.

Connecting bare wire

Strip a short length of the sheath, twist the fine strands together so none stray, and insert them fully into the terminal before you tighten it. Spring terminals take the bare end directly; binding posts take bare wire wrapped round the post or a banana plug if you prefer a cleaner finish. Check that no loose strand touches the neighbouring terminal, and give each connection a gentle tug to make sure it holds. For a system that is moved often, banana plugs or a terminated speaker lead save stripping the same ends again and again.