How to wire speakers – an essential guide

Understanding the basics of speakers wiring

Everything in a speaker can affect the sound of your system, from the type of conductor material to its thickness (or gauge), and from the insulator material covering the conductor to the arrangement of the conductors within that cover, from solid single-strand designs to bundles twisted together.

All speaker cables are bad, in that signal will be lost in the transmission from amplifier to speakers, and the longer the cable, the greater the loss, as the resistance of the cable will turn some of that precious electrical energy into heat. So, choosing the right cable is a matter of mitigating those losses and getting as much signal as possible through to the speakers.

Don’t get too hung up on super-thick high-end cables snaking across the room, as a good-quality cable of reasonable gauge will be more than adequate, even for fairly long runs between amplifier and speakers.

Choosing the right speaker wire

There’s a lot of mythology and pseudo-science in the world of speaker cables, with outlandish claims being made for exotic materials and cable constructions. But much more important is getting the right cable for the application in which you’re going to use it.

For example, very thin wire may be more convenient to hide away, but on longer runs it will lose more signal than thicker designs. Thinner wire is therefore best suited to ambient listening, where your speakers may be positioned some distance from your amp and you’re willing to sacrifice a little fidelity. For your main setup in your listening room, or even just the living room, a thicker cable designed for audio will give the best results – look for conductors of at least 2.5 mm2.

For longer runs above around 5 m, a more substantial cable with a multi-conductor (or multiple bundles of conductors for more cross-section, may be preferable to minimise losses. You’ll then need to decide whether the extra cost of such cables, especially for longer runs between amplifier and speakers, is an investment you’re willing to make.

Bear in mind, too, that you should use cables of the same length, even if one speaker is closer to the amplifier; this ensures the "cable effect" will be the same for each channel, even if it means loosely looping up the extra cable – never coiled tightly – behind one speaker or your amplifier.

You may find that an amplifier manufacturer specifies using a minimum cable length with their products or recommends against using cables with exotic materials or constructions with their products. It could be that the amplifier has been designed with minimum protection or a certain cable/speaker impedance. Fortunately, amplifiers such as this are rare these days, meaning that any well-constructed speaker cable will work perfectly well.

Connecting speakers to amplifiers

There are two main considerations when it comes to connecting speaker cables – getting the polarity of the connection right and making sure you make a clean, strong and durable fit between the cable and the terminals.

Polarity is vital – most cables are colour-coded red and black or marked in some other way (such as a rib on the insulation of one conductor) to allow you to identify the conductors at each end of the cable. This ensures both speakers will operate in the same way: get the polarity reversed to one speaker and – while you won’t do any damage – the fact that the speakers are working in opposite polarity will destroy the soundstaging, detail and all sorts of other hi-fi niceties.

So, red to red and black to black: the easiest way to ensure this is to have colour-coded connectors on the end of the cables to connect to the amplifier and speakers. What kind of connector depends on the terminals you’re connecting to. Here are the main types of connectors you’ll encounter:

• Banana plugs – These are the most common connector type and are the simplest to use. Simply push them into the terminals and you’re ready to go.

• Spade connector – These flat-bladed connectors are also quick and convenient to use. Simply insert them at the base of a speaker’s binding posts and tighten to secure them in place.

• Bare wires – If you aren’t able or choose not to use banana plugs or spade connectors, you can simply strip the end of the speaker cables and connect the exposed wire. You’ll typically use bare wires for components equipped with spring-loaded terminals.

But should you use bare wire connections? Well, there’s a theoretical advantage in that there’s a direct connection between cable and terminal, with no connector "in the way". However, practical considerations include the possibility of accidental short-circuits caused by stray filaments of wire and the fact that bare wires, especially copper, will oxidise over time, affecting the connection.

There are ways around this last effect, including using longer speaker cables and stripping them back a few centimetres every six months or so to remove the tarnished bare ends. However, a better solution is to have your supplier make up and terminate the cables for you, crimping, soldering or – in a few cases – welding the plugs onto the end of the conductors. This will ensure a secure and durable connection that will reward you with years of service.

That’s especially the case when bi-wiring or bi-amping speakers, having first removed the jumper bars on the terminal panels to separate the two crossover sections. Professionally prepared cables can be labelled with 'HF+', 'LF-' and so on, making connections much simpler. Four-conductor speaker cables are available for just this purpose, so you can bi-wire or bi-amp with just a single run from your system to the speaker to keep things neat and tidy. For more information about bi-amping, check out our guide to bi-amping speakers.

Here are a couple of ways to ensure your connections are secure and you keep signal loss to a minimum:

• Tighten your terminals on the speakers and amplifier, then wiggle the cable and tighten again. Do this three times and repeat after every six months of use, as terminals can work loose over time.

• Use contact cleaner on your plugs and binding posts every six months.