Serious stuff. No less than 500 Watts of high efficiency Class D amplifier power, with a (12" long-throw driver in a hand finished MDF cabinet. As you would expect, bass extension is more than generous - but what's really impressive is the way the LF response is immaculately controlled.

Output level, phase (infinitely variable) and the low pass filter frequency can be adjusted via radio remote control from anywhere in the home, so the unit can be concealed wherever you please.

KefÂ’s finest hour - a subwoofer to rival the best.

By Max Christoffersen, July 2003

Kef PSW4000 subwoofer. $3999

You can tell a lot from the way a company packages its products. The obvious care and concern that wraps manufacturerÂ’s products snugly and safely says something about attention to detail.

And from the extensive cardboard packaging to the silk tissue wrapped cone feet (petanque anyone?), you get the feeling this is something special.

To use the parlance of modern marketing jargon, here is the audio embodiment of a commitment to excellence. So let me cut to the chase: This KEF oozes quality. It reeks of sophistication. It positively breathes class.

From the beautiful inlaid glass top, to the finely machined custom shaped feet, to the gold-plated binding posts and Canon connectors to the on-screen display (!) – this is a sub for those who want something sublime.

And from the minute you get your first glimpse of this sub among the extensive packaging, you know youÂ’re about to unpack something special.

Because this is the subwoofer you want because it sounds so good and your partner wants because it is such a pristine piece of furniture.

Sometimes being in the company of such fine equipment makes you aware that all this quality and attention to detail isn’t just a happy accident. Some engineer somewhere, has been thinking. And the Kef engineers have been doing a bunch of thinking – likely asking the following question: ‘What if we did...’

And the answer to many of those ‘what if’ questions is delivered in this fine piece of audio.

I have to admit Kef wasn’t always so welcome in my home. Over the years I’ve heard a range of Kef products that have ranged anywhere from the ‘Everest’ of outstanding audio to ‘The LA Valley’ of ordinariness. Like many other UK companies, Kef have had their share of ups and downs, but the PSW4000 is certainly an up.

In the PSW4000 subwoofer Kef have delivered at their best. All the sonics, the build quality, the useability and the all-round texture and warmth of sound makes this possibly the best 12" subwoofer IÂ’ve used.

Among its great attributes is the fact that it doesnÂ’t have the occasional negative sonic signature of ported subs. There is no huffing and chuffing from the down firing 12" driver and port mouth as it reaches its limits. Nor any sign of the unwelcome overhang quality that I personally donÂ’t prefer over the more direct and tactile route of air suspension subwoofer designs.

Here then is a subwoofer that pushes the right buttons: It’s a ported sub with no ported over hang. And what you’re left with is a very smooth and seductive feel that has that nice sense of tactile extension when the driver is working hard, but is also coupled to an ability to render fretless bass in that smooth style that says ‘this is the way it should be done’.

It may not be the sub you use to scare your friends with prodigious slam - but it is the sub you use to recreate what’s really on the soundtrack or musical performance all the way down to 25 Hertz. There is a high ‘ooooooooohhh yes’ factor with this Kef, which only gets better the deeper you go.

It weighs in at 38Kg. The PSW4000 comes with a range of user friendly facilities including auto-on and Canon (balanced connectors) as well as high quality gold plated five way binding posts for those choosing to drive the unit from their amplifier speaker leads. Phase control, level control, crossover frequency (40–140Hz) and a music cinema switch are also included. And the long throw 12” driver uses an ‘abundant’ rubber surround.

Among the useful facilities is a small bar level indicator on a transparent front panel showing what output level the sub is being driven to. ItÂ’s a genuine handy feature that allows the user to get a good feel for the output level and alter it using a visual reference. YouÂ’ll need to be close enough to see it, but itÂ’s not a gimmick.

Last is the small remote that provides control for phase, frequency level and power on/off (mute) and a movie/music switch that lifts the subwoofer level although by how much the manual wouldnÂ’t reveal.

As always, the usual caveats of subwoofer placement apply: try various locations as low bass is not wholly omnidirectional allowing for placement any old place.

The end of this saga of audio quality is that you wonÂ’t want for anything else. KefÂ’s sonics, construction, appearance and performance combine to make the PSW4000 what it is: English audio at its finest.

Frankly I canÂ’t imagine what the PSW5000 would do!

This product was tested by KEF to make sure it still works perfectly, and then repackaged for sale at a significantly reduced price. Any scratch or dent on these products will be only skin-deep (most canÂ’t be seen); we guarantee that they'll perform just like brand-new. All accessories are included, along with KEFÂ’s full 5 year warranty (1yr on amps)

*Quantities are VERY limited and the selection changes frequently!