French company Cabasse has redefined the notion of high-end loudspeakers with the creation of a speaker system that costs almost as much as a base model 2009 Ferrari F430. But for your UK£108,000 (US$176,000), you're buying a monumental engineering achievement - the world's only four-way, point source speaker system (more about that after the jump). This audio perfectionist's dream required a spherical enclosure - which means you also have to accept the fact that two giant, ugly eyeballs on sticks will be watching you enjoy some of the best audio reproduction, sound staging and stereo imaging the world has ever experienced.

4-way point source... huh?

Cabasse claims that its La Sphere speaker system is the world's first and only 4-way coaxial point-source loudspeaker. That's lovely - but what does it mean?

Well, 4-way speakers, as most would be aware, are speakers that use four separate cones to replicate the breadth of the audio spectrum. A large 'woofer' cone handles the bass, using a big vibrating membrane to push the large amounts of air needed to get a rich bass sound. A small 'tweeter' cone handles the delicate high frequencies, and two more cones are dedicated to low and high mids.

Imagine a tall speaker box with those four speaker units in it, arranged with the tweeter at the top, and the woofer down the bottom. Now, imagine what happens to the sound waves that come out of those four speakers. You can think of each of those speakers as a point in a perfectly flat pool of water, and you can visualise sound waves as if you're dropping four stones into the water right at the centre of each of those speakers.

With four separate points, you'll find the sound wave ripples will almost immediately get very confused as they cross over each other and the waves interact. But if you drop a single stone into a flat pool of water, the waves will reach the edges undisturbed. The same principle applies perfectly to sound waves as well - 4-way speakers with multiple point sources for the sound produce messy and confused signals as they reach the ear.

If, however, you can arrange all your speaker cones in such a way as to place each cone's centre of wave propagation at exactly the same infintesimally small mathematical point in space, you can produce clear, undisturbed soundwaves that reach the ear without multiple-point source interference. The effect is increased clarity and more accurate sound representation - as well as better "imaging" - or placement of the sounds in stereo space.

So you can appreciate the technical and mathematical challenges involved in building a speaker that mounts four separate cones for accurate representation of the frequency spectrum - positioned in such a way as to have a unified sound emanating from a single point source.

La Sphere

Cabasse achieved this lofty goal by mounting the coaxial speaker cones in a spherical enclosure around 28" in diameter. Theoretically, a spherical shape allows an infinite number of membrane diameters within it that can push sound out from a single point.

Practically, it's very expensive to achieve, as evidenced by the stratospheric price tag the speakers carry - 108,000 UK pounds, or roughly US$176,000. This accounts not only for the massive R&D task and long hours of mathematical modeling it took to design La Sphere, but also for the expert installation service and the no-compromise materials used in construction - many of which are usually more at home in aerospace programs. Learn more about the speakers' construction at the Cabasse website.

Cabasse claims that La Sphere delivers perfectly linear sound response right up to 25,000Hz - well above the generally accepted 20,000Hz ceiling limit for human hearing, and reviews have generally been very positive about the sonic experience they can deliver. You'd hope so - in ordering a pair, you're sacrificing a pretty amazing sum of money.

And it has to be said, while the spherical shape is absolutely necessary in order to achieve the system's sonic goals, La Sphere would look like two enormous webcams peering at you in your listening room. It's hard to imagine them blending in with the decor. A system for incredibly rich, blind audiophiles, perhaps?

Either way, La Sphere is an astronomical engineering achievement and a monument to sonic purity, linearity and uncompromising commitment to a single point source. The question remains - what musical recordings would be worthy of such a system? I need some new listening material - let me know in the comments below!

La Sphere will get its first public showing in the UK at the upcoming National Audio Show, 26-27 September, Whittlebury Hall, near Silverstone.

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