Audio Advent 2021 Day 12: To Bi-Amp or not to Bi-Amp?

In a previous article I explained why many speakers have four terminals on the back, and the explanation I gave was to do with bi-wiring. Now, while that is true, you can actually take it a step further and use a technique called bi-amping as well as bi-wiring, to really get the best out of your loudspeakers. 


In the article about bi-wiring I explained how the double set of terminals are used to send the high-frequency signals and low-frequency signals along separate wires to each speaker, rather than interfering with each other along a single wire and then being separated at the crossover. Bi-amping follows a similar principle, however you are not just separating the differing frequencies by wires, but also by amplifier. In the simplest terms, you have one amplifier producing the signal for the bass drivers, and a separate amplifier producing the signal for the tweeters, giving you both more amplification power and an even purer signal to each driver. 


There are two types of bi-amping, but the most common is known as ‘passive bi-amping’, and this is because it works with any pair of speakers that have four terminals on the back, and requires no extra kit other than the cables and amplifiers. It is possible to use one modern multichannel amplifier that can assign its output to different channels, employing the use of the extra output terminals on the back that might be labelled ‘surround sound zone 2’ or even ‘bi-amp’, but that’s really missing the point. We’re trying to reach audio nirvana here, which doesn’t mean taking shortcuts!

So, to set up, take your two amplifiers, and choose one for bass and one for treble. On the back of each you will have four terminals, so eight terminals in total across both amps. Take the speaker cable from one pair of terminals on your bass assigned amplifier to the bass terminals on your left hand speaker. Then take the speaker cable from the other terminals on the same amp to the bass driver of the right speaker. Repeat from the treble assigned amp to the tweeter terminals on both right and left speakers, and you should end up with a system looking like the diagram above.


With this system, it is imperative that you use identical cables for both left and right treble and bass channels, as well as identical amplifiers, or if that isn’t possible, ensure that they are from the same manufacturer and have the same input sensitivity level. This is to avoid either your tweeters or your drivers being louder than each other and changing the balance of your music for the worse. 


The main advantage of this setup versus a single amped and single wired system is the power delivery; doubling the number of amplifiers naturally doubles the amplification power you are putting in to your speakers, which might at first sound risky, however you are actually far less likely to damage your speakers with a bi-amped system than with a single amped system. The extra power is not always used, however having power in reserve will pay dividends when you come to play rich orchestral music, a huge atmospheric rock concert recording, or texturally complex pieces, such as Jacob Collier's for example. Here you will immediately notice the music opening up, instruments appearing that you hadn’t heard before, and the soundstage enveloping your listening room. And to follow on from my point about this being less taxing on your speakers’ drive units and crossover, think about it as the amplifiers doing less work for a better result. Working smarter, not harder, as the saying goes. And more technically, a less powerful amplifier having to work harder to produce the better sound is more likely to send out a distorted signal, damaging the electronics in the drive units. Of course, you are also keeping all the acoustic benefits of bi-wiring when you bi-amp, so the improved signal isolation and purer electronic path from amp to speaker is carried over, just with the added benefit of more power!


So, what do you actually need to set up your bi-amped system?

Well, to start with, make sure your speakers support bi-wiring by checking that they have four terminals on the back. Then you are going to need two PAIRS of speaker cables, so four individual cables in total. I’m afraid the bi-wiring cable I mentioned in my previous article won’t work here, as the cables are going in different directions. And finally, you will need either a multichannel amplifier as I mentioned above, or an integrated amplifier with a matching power amplifiers, such as the Arcam PA240 and Arcam SA30.  The next level up would be a pre-amp with two power amps - we've had a lot of success with the Parasound range here, starting from the more affordable end of the scale with the Zpre 3 and Zamp V.3, but going right up to the Halo JC2 BP pre-amp and Halo JC5 Power Amplifier. However if you really want to take it to the next level, the ultimate in resolution is to have a pre-amp plus four monoblocks, meaning each driver has its own amplifier! We'd recommend the flagship pre-amplifier from Ming Da, the MC300, and 2 pairs of the Dynasty Potente mono blocks. 


To conclude, yes, we completely recommend bi-amping! It can, and will, make a noticeable difference to the overall performance of your system, as well as protecting your speakers and providing oodles of grunt when the music calls for it. If you would like to listen to a bi-amped system, do get in touch and we will be happy to either arrange an appointment for you to visit our Lincolnshire Showroom, or for us to bring the equipment to your house for a home demo.

1 comment

Andrew Dalling

Andrew Dalling

Hi..ok, I bi amped arcam alpha 8r with the arcam alpha 9power amp into pmctb2+ speakers using blue heaven interconnects for at least was quality sound..however, the amps started to show signs of age , crackling etc so I took advice of local audo t n decided renew complete system ( der, I know know)..I’ve now use pmc twenty5 22,s…arcam CD, chord qutest dac, rega oethis amp using chord comp speaker wire n now red dawn inters.. (2 channel)…sounds ok but no where near as good as previous..PLEASE HELP…

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