There are many ways to upgrade your system, and as you'll no doubt be aware, they don't all involve being pummelled into sales submission in a dark listening room, then sheepishly handing over the last remains of your bank account in return for a high-end SACD player (all the while knowing that upon your return to the family home, the words, “you bought what!?” will be louder than any hi-fi).
No, you have options. And one of the simplest ways to give your system's sonic presentation some much-needed zest is to bi-wire your speakers. However, there seems to be a lot of confusion about exactly what this means and what the options are. And when it comes to taking it a stage further and actually bi-amping your system, it would seem that confusion turns to chaos.
Bi-wiring - what it means
So here are some answers. The simplest connection between amp and speakers is a basic two-conductor cable. One side is positive (marked with a '+' symbol and/or red plugs and terminals), and the other, negative (and white). This cable transmits the signal to the speaker, where it goes into a crossover. This is a circuit that splits the signal between the drive units - treble to the tweeter, and the midband and bass frequencies to the aptly named mid/bass driver.
But a standard crossover can have its problems: with just one pair of conductors delivering the entire signal, there is a danger that the lower bass frequencies can affect the transmission of the more delicate and subtle treble frequencies, thus causing a deterioration of detail and subtlety in the sound you hear.
So instead, bi-wire. Bi-wiring your speakers involves using not one but two pairs of (positive and negative) conductors from the amp to each speaker: this means that the mid/bass signal and the treble signal are kept completely separate.
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What you need
For this, you need speakers specifically designed for bi-wiring. The most important component here is the bi-wirable crossover, which is, to all intents and purposes, two separate circuits - one to filter the treble out of the signal for the bass driver, the other to prevent the bass from reaching the treble driver. Recognising if a speaker is bi-wirable is very simple: just look to see if it has four, rather than two, terminals. (And if it has six terminals, that means it's a fully three-way speaker you can even tri-wire if you want to…).
But although you need speakers that are especially designed for bi-wiring, your amp, on the other hand, doesn't need to be specifically designed for the purpose. Unless your amp has only those annoying springclip terminals, you can bi-wire just about any amplifier. Many amps carry twin sets of speaker outputs for just this purpose, or for driving speakers in a second room, but either way you can use them for bi-wiring.
If your amp has just a single set of outputs, simply connect the two positive conductors from the left speaker to the '+/red' terminal, and the two negatives into the '-/black'. Repeat this for the right speaker. And if you have an amp with 4mm banana socket terminals, most cable manufacturers and dealers will supply bi-wire cables with single plugs on the end to make this even easier.
Bi-amping - what it means
If you want to take things a stage further, bi-amping causes an even more significant improvement to the sound. Any speaker that can be bi-wired can also be bi-amped, but in this case it involves using one whole channel of amplification to drive each individual driver. So, in this configuration, you have a system with four channels of amplification - ie two stereo amplifiers - with each speaker having its tweeter driven by one channel, and its mid/bass driver by another.
There are a number of ways to arrange this: you can use a preamp with two separate power amps (or four, single-channel monoblock amplifiers), or an integrated amplifier with a single stereo power amp added. In this last arrangement, you'll need an integrated amp with pre-out sockets.
In this case, it's also worth noting that your integrated amp and power amp need to well matched, otherwise you'll have problems: the best idea is to go for same-brand products that are designed to work in tandem.
What you need
To bi-amp your system, you'll need to have four connectors at the amp end of each speaker run. Simply use all four speaker outputs of one amp (left + and -, and right+ and -) to drive one speaker using all four of its bi-wire terminals. The two amps are simply connected together using a pair of interconnects: go from the pre-outs on your preamp (or integrated, if you're using one) to the pre-ins on the power amp. Simple!
Each stage of these upgrades has a similar effect, only more so as you ascend the upgrade ladder. In its most elaborate form - four discrete monoblock power amplifiers, each driving a single driver in your speakers - the difference it makes can, in the right system, be immense. The sound is clearer, more cleanly defined and confident. And most of all, the dynamics of your music are rendered with much greater ease, clarity and subtlety.
What you get
Whether simply decide to bi-wire your speakers, or go the whole hog and bi-amp them too, these upgrades are usually worth the effort, and can be achieved for relatively little money. Going down this route might cost you a lot less - in both cash and family harmony - than that expensive component upgrade you were considering.
