Review

Epicentrix Complete Review - Australian Hi-Fi Best Buys - Australia

26 Jun 2007

When purchasing a home theatre speaker system, few customers realise that the centre channel speaker is the most critical speaker in the entire set-up, much more important than the (usually much larger!) front left and front right speakers.

Why? Because when you’re watching a movie, or listening to any type of video with a multi-channel soundtrack, it is actually the centre channel that’s doing the lioness’ share of the work, reproducing all the dialogue was well as many of the sound effects.

The problem with this is that almost all centre channel speakers are too small to deliver realistic sound levels, particularly in the lower midrange regions, or to be a proper acoustic match for the front left and right channels. The drivers are also often poorly positioned on the front panel, which leads to poor off-axis performance, so the only person who’ll benefit from their already limited performance is whoever sits smack-bang in front of the screen.

At this point, you’re probably asking why, if all of the above is true, are the great majority of centre channel speakers so small? The single word answer is breathtakingly simple, but at the same time insufferably tragic. Marketing. That’s right. Speaker manufacturers build small centre channel speakers because their market research shows that the great majority of consumers won’t buy large ones.

The closest most get to a workable solution is to down-size their front channel speakers to be the same size as the centre channel. Properly handled – and always provided the centre channel isn’t too small – this can be a practical solution, but the smaller front left and front right speakers then introduce practical difficulties of their own, particularly if you also use your system to listen to stereo CDs.

As you have probably already gathered, there are still a few – precious few! – loudspeaker manufacturers in the world that are not prepared to sacrifice sound quality simply in order to increase sales. That Krix is one of these select few is evidenced by this Epicentrix centre channel speaker, which is 900mm wide, 360mm deep and 218mm high and tips the scales at a back-breaking 24kg. And instead of the usual three-driver/two-way design, the Epicentrix is a full six-driver, three-way design. And instead of the usual sealed enclosure, which restricts bass response, the enclosure is a bass-reflex design, with front firing ports.

Four of the six drivers are identical, and operate in tandem to ensure that the Epicentrix can deliver high levels of bass, particularly at very low frequencies. Although the driver sitting immediately below the tweeter looks externally identical to the four bass drivers, it’s actually a dedicated midrange driver with a different magnetic circuit. Because Krix is using only a single midrange driver, there are no interference effects for off-axis listeners, ensuring greatly enhanced sound quality for those listeners.

Note also that Krix has squeezed the acoustic centre of the midrange driver as close as possible to that of the tweeter by actually physically overlapping the frames of the two drivers. This ensures correct spatial imaging. Krix also provides the midrange with its own sealed enclosure, to ensure its performance cannot be affected by the rear energy from the bass drivers, but also to optimise its own frequency response and operating bandwidth.

The 26mm tweeter is a very high-spec unit usually reserved for use on high-end two-channel speakers. You might recognise it by its unique dual concentric diaphragm and central waveguide. There are several lower-spec versions of this design available, but Krix is using the premium model, which is rated out to 40kHz. It assumes its duties at around 2.5kHz, which is high enough that it’s able to handle plenty of power.

The bass drivers (and mid) all have coated paper cones, rubber roll suspension surrounds and presses steel chassis. The paper cone means minimum mass, for a nice, fast action. The drivers have a diameter (overall) of 152mm, but the important Thiele/Small diameter is 106mm, for a piston area (SD) of 88cm². However, because there are four bass drivers, the SD of the speaker is 352cm², which means that if Krix had used just a single bass driver, its diameter would be about 210mm. (So you can see why you need four bass drivers!). The bass drivers cross to the midrange at 340Hz.

None of the drivers in the Epicentrix are shielded, so you can’t use the speaker close to an ordinary CRT television set – the powerful magnetic fields would result in severe picture distortion. However, they would not affect plasma or LCD screens. (When we queried Krix about the lack of magnetic shielding, they replied that they thought that anyone likely to buy an Epicentrix would own an LCD, plasma or projection TV.)

Speaking of plasma and LCD, we found that when it came time to install the Epicentrix its size is actually a blessing, because in fact it’s large enough – and more than strong enough! – to easily support even the largest LCD or plasma screen. If your projector screen is acoustically transparent, you won’t even see it.

We positioned the Epicentrix midway between a pair of Krix’s Neuphonix, with which it’s designed to be the closest timbral match, and were floored by the quality of the sound and the seamless way sounds shifted across the front sound stage. But we were more floored by the sound of the Epicentrix itself, so rich and powerful that on occasion we wondered if we really needed the Neuphonixes there at all (a question quickly answered whenever on-screen sounds moved to extreme left or right). Unlike almost every other centre channel we’ve ever heard, the Epicentrix remained excitingly dynamic and wide-range no matter how the movie sound engineers panned it across the front sound stage. And when listening off-axis, not only was the image location still correct, but also the tonal balance, with no fall-off at high frequencies, and a continued smooth, balanced midrange sound.

Conclusion

Yes, the Epicentrix is large, but under a plasma or LCD with the lights down, you’ll never know it’s there – until the soundtrack leaps out, and you realise that you’re in for the finest movie sound experience of your life!

- Australian Hi-Fi Best Buys - Australia , Greg Borrowman

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