August 2002

Bowers & Wilkins' Nautilus 800 Loudspeaker
An unusually refined and articulate high end, wide bandwidth loudspeaker.
Review By Alvin Gold

  The B&W Nautilus 800 has an impressive pedigree, though not one that has always carried a great deal of weight at the high end. Its immediate predecessors are the 801 and the 802, but the 801 is the key model here. Prior to the Nautilus 800, this was the senior model in the range, built around a massive curved ply bass enclosure housing a 15" bass driver, with a surroundless midrange unit in a pod above, and a Nautilus tune metal dome tweeter in top of that, the two smalls units mutually decoupled to reduce intermodulation. The 801 become a mainstay in the studio world where a neutral balance and high SPLs were required. They were extensively used in EMI's Abbey Road studios for example, including in their first multi-channel control room, which employed five of the beasts driven by massive Chord amplifiers. The 802 was not quite the domestic counterpart, but that is how it often seemed. It used broadly similar ideas and packaging, but instead of the 15" driver, it used two eight-inch units in a slimmer and more manageable enclosure. The 802 formula meant less bass, of course, but it was still a big beast by normal standards, and in many ways it was the better speaker in day to day use. Although it was the less ambitious speaker of the two, it did a more limited job better, in my view.

It quickly became clear that the 801 and 802 did not have all the bases covered after all. I have been in dispute about this with B&W from day one, but in my (admittedly limited) experience of the 801, it simply failed to work properly. It needed large spaces to breathe properly, and it was also apparent that it was a destroyer of amplifiers par excellence. I never heard one with a big Krell amplifier in charge, but my guess is that this would have been one of the few amplifier brands with enough discipline and control for the task. With the amplifiers I heard, which have included an ancient Sony Esprit model with a switch mode power supply, but also more recent and apparently suitable amplifiers from Classé and Levinson, it still managed to deliver bass with all the incisiveness and precision of a wet Thursday afternoon. The last of these amplifiers is worthy of note: the Levinson was B&W's own, installed in their main listening room at their R&D center in Steyning, a rather pretty village about 50 miles south of London, not far from Brighton on England's south coast. On that occasion, I was able to listen to all three 800 models playing one after another, using program material that I bought for the purpose, and this laid to rest any residual feeling that I might have been overly hard on the N801.

The N800 clearly comes from the same school at the two earlier models. The midrange and tweeter look the same, though appearances can deceive and there are some subtle but highly significant differences, as we shall see. The bass end is also conceptually similar, with an enclosure constructed in much the same way, but the driver complement is all new: consisting of a pair of 10 inch units whose total radiating area is about the same as the 801's single 15 inch unit. Bass extension is therefore roughly the same, but the way it goes around achieving it could not be more different.

One point to note is that the 800 is available in two versions, one of which is the Nautilus 800, which is as described below. The other is the Signature 800, which costs significantly more - $20,000 pair against $16,000 for the N800 - for comparison the 801 costs $11,000, and the N802 $8,000 a pair (sales taxes excluded). The ghost at the party is the original snail-like Nautilus, which was originally designed as a technology demonstrator, and which is still available a four way full active loudspeaker with an external crossover network, for a cool £35,000 a pair in the UK (presumably about $45,000). The differences between the Nautilus 800 and the Signature 800 are purely cosmetic. The Signature is finished in something called Tiger's Eye, which is what happens when real wood veneers are transformed by an exotic Italian Tiger's eye machine. I haven't seen one of these, but my mental picture is a refugee from Hades half hidden in steam, which takes in unsuspecting wood veneers at one end, and stirs them tightly, before spitting them out as a convoluted, highly figured finish, which in the S800 has grey figuring and is then dressed in a deep piano gloss covering. To my eyes, the Signature is worth every penny; it looks stunning, but it's strong meat and not everyone likes it. Most of all it does nothing for the sound. Under the skin, the two models are the same, so buy the S800 for its looks, or reject it on cost grounds. Your choice.

The Same, Only Different
Although the 800 is only a moving coil loudspeaker, and there is nothing intrinsically exotic about the ingredients, it is a moving coil like no other. Many of the design specifics are extremely unusual or simply unique. There is nothing new in the idea of tacking enclosure resonances and internal reflections for example, but the lengths that the designers have gone to here border on the obsessive. Witness the massive, deeply curved main enclosure, which is fabricated in 38mm multi-layer ply and heat formed to its final profile, a task that lies outside the scope of loudspeaker manufactures, including B&W who employ an outside contractor more used to manufacturing high grade furniture. The curved cross-section, with the flat base and angled top (faced in Connolly leather by the way, just like your Rolls Royce Corniche) have no parallel surfaces, and the curved section adds immeasurably to the stiffness of the bass enclosure. But this isn't the extent of the anti-resonance measures, as this is a full Matrix enclosure, whose structure subdivides the internal cavity into a large number of small interconnected cavities with internal open cell absorbent foam wadding which stiffens the enclosure still further. The main enclosure is tuned by a downwards facing port, a so-called Flowport, which is has a deeply flared section at the business end like the bell of a trumpet, which is covered in golf-ball like dimples, which helps reduce turbulence and 'chuffing', and according to the designers, compression at high SPLs.

The two 250mm bass drive units are ostensibly comparable to previous Nautilus bass units, with a cone made from a low density material that includes Kevlar, resin and paper, and scaled to the dimensions required. But there have been modifications to the surround to improve timing, and a longer coil and a double-mirrored spider to improve control. There have been other changes too: the lead out wires have been improved, and the massive center domes, included to reduce 'cavity' type colorations, is now supported internally by an improved mushroom stalk like extension to the carbon fibre voice coil former.

Important as the bass section is in this or any other worthwhile full bandwidth loudspeaker, the most important part of the frequency band is the midband, which uses a Kevlar woven cone but without the usual roll surround. Instead the cone bears on a foam ring which has a mechanical impedance similar to the cone itself, and which absorbs standing waves that are normally reflected back from the edge, muddying the output. Although it is quite a large size cone for the frequency range involved - 350Hz to 4kHz are the crossover center frequencies - the design is designed to have a smoothly reducing radiating area with increasing frequency, a design aim aided by the fixed suspension, so that as the tweeter crossover frequency is approached, the effective diameter of the cone becomes much smaller than its nominal diameter. The unit is also notable for its skeletal diecast basket, which is designed to place the minimum acoustic load on back radiation from the cone. The unit has been modified for the N800 compared to the very similar looking units used in the 801 and 802. With a longer gap, allowing greater excursion for given distortion levels. The unit is housed in a curved mineral loaded synthetic housing - a material called Marlin - which is modified by a rear extension reminiscent of the Nautilus tube loading, which effectively detunes the enclosure and disperses back radiation from the cone. Compared to previous incarnations, the N800 midrange has gained a new and better center plug, the magnet has switched to neodymium-iron-boron from ferrite, which is less bulky and presents less acoustic loading on the cone, and a thicker top plate enhances linearity and reduces distortion.

The tweeter uses a full Nautilus tube behind the aluminum dome, but again there has been subtle behind the scenes tweaking, with an aluminum coil former replacing Kaptan, and the center pole is silver plated to act like a 'shorted turn', with the result that coil inductance varies less with displacement, reducing distortion. The first main HF resonance also moves up, from 29kHz to well above 30kHz.

The final element in the design is the plinth, which provides a standoff which allows the port to do its stuff, and which accommodates a new and completely respecified crossover, which uses ultra high power components including air core inductors throughout, and higher quality polypropylene caps. The plinth adds little to the design visually, but it is sealed, which reduces microphony, and the custom spikes allow some tilting of the enclosure to fine tune the vertical listening axis. The system is bi-wireable and can be bi-amplified via two sets of WBT terminals. Unfortunately B&W decided mot to go full hog with a tri-wireable network, citing the confusion that would cause. Their view is that few would use such a facility in practice. To put it all in perspective, this is a loudspeaker that measures around 47 x 18 x 25 inches, and which weighs a backbreaking 275 pounds apiece. Make sure the girlfriend/wife/sprog lend a hand.

As I write, I have been living with the N800 on and off (mostly on) for about two months, and have used it with a wide range of amplifiers, some relatively inexpensive, but including a number of mid-market pre/power combinations, and including also some exotic machinery from Classé and Krell, up to and including the Krell FB700cx, the largest of the new stereo range with a power output of 700 watts/channel, which on paper at least the N800 is well qualified to handle. My initial expectations however based on the 91dB published sensitivity figure was that power would not be the issue, and indeed this was partly confirmed by my initial trials with a range of loudspeaker cables, which clearly and unequivocally showed that Nordost Valhalla was the best choice of the cables available to me, even though Valhalla doesn't immediately suggest itself as an obvious candidate for high power systems. Following experimentation, I concluded that bi-wiring should be regarded as a prerequisite.

I was wrong about the amplifiers. The N800 makes good use of as much power is available, partly because its extended operating bandwidth, with the -6dB point at 25Hz, means that it draws current heavily at low frequencies, and also because its impedance is very low over much of the midband, despite a nominal 8 Ohm overall impedance. Most of all, the N800 is unusually transparent, and it is all too easy to hear what amplifiers don't do, or do wrong, especially in a comparative environment. In particular it is easy to hear when amplifiers change in sound at different volume levels, effects normally masked by even greater level dependent mechanisms in the loudspeaker itself. But even at quite restrained volume levels, where these mechanism are not in play, the N800 lets you know with unusual clarity just how an amplifier sounds, and this sets in train a virtuous spiral that will inevitably end up with you paying quite a lot for a matching amplifier to make the most of the B&W. And not just any old expensive amplifier either: you can forget all about tubes for example. They just won't have the bottle, excuse the pun.

Musically Speaking
Just as the N800 is fussy in the ways described above, it is surprisingly docile in other ways. In many ways this is not a big sounding loudspeaker. It is a small one writ large, with all the speed and consistency so characteristic of good compacts, and so rarely found in larger loudspeakers, however good. But anyone used to the 801 in particular is in for a big surprise. The balance is completely different, largely down to the changes in the way the bass to midband balance has been optimized. The N800 is lean, almost dry in balance. The bass goes deep - very deep, and if you're in any doubt try the final movement I Pini della Via Appia from a good recording of the Respighi Pines of Rome (I used the Lorin Maazel/Pittsburgh version on Sony) and see how the sheer physical force of a large orchestra creeps up on you. Starting with a barely audible rhythmic murmur, almost a presence without sound, and ending on a cataclysmic crescendo, the N800 goes deep, deep enough that you could almost count the individual compressions and rarefactions in the air. But even with a degree of boundary reinforcement, it never sounds heavy handed, slow or lacking in pitch definition. The N801, under similar circumstances, sounds much fuller, though not deeper, but pitch information is muddled, and the musical architecture is confused. The differences really are as plain as a pikestaff, and twice as dramatic.

The mid and top are just about ideal, and certainly extremely difficult to criticize. Of course some will naturally gravitate to a different kind of balance altogether, but in contrast to most high-end loudspeakers, the N800 doesn't really have an individual voice. At least it is not obviously colored. The sound of the B&W really is the sound of the music itself, with a mild contouring superimposed at the lowest frequencies, and perhaps without the class leading ultra-transparency of a loudspeaker like a Martin-Logan. By any normal standards, however, the N800 remains uncommonly transparent, and the treble has a sweetness and precision quite out of the ordinary, one reason perhaps for the lack of grain or edge when things become hot.

Although the N800 is understandably impressive with music with the kind of bold architecture epitomized by the Respighi, rather surprisingly it is just as impressive with much smaller scale works. There is nothing bloated about the sound of a string quartet N800 style, and piano quality has the right metallic attack, and a natural delay without bloom or overhang. Tellingly, voice reproduction has a sweetness and air quite out of the ordinary, and I could cite here a number of artists, classical and otherwise, but that would be to miss the point. And the point is that the N800 treats all voices well, including male radio announcers speech, which is reproduces largely free of the common box induced chestiness. But open up the throttles for some full scale choral music, and the sound swells almost without limit. This is also a loudspeaker that knows how to rock & roll, again with that trademark on the ball timing, and the ability to push bass lines without undue emphasis giving the sound an almost understated quality.

All the time, the loudspeaker has a quality of consistency. There is no discernible change in voicing as the volume shifts gear, still less any obvious signs of stress at the volume levels I was able to try, which were fairly substantial (for short periods of time, unfortunately, neighbors being what they are). But there is more to this loudspeaker than just a neutral and extended balance. Despite the large size of the midrange unit, and the unusually high mid/tweeter crossover frequency, the N800 works consistently over a wide lateral arc. Clearly the unusual geometry of the system plays a part here. The shrinking radiating area of the midrange driver combined with the smoothly rounded housing encourages unusually wide low diffraction dispersion, even towards its HF cutoff. And the tweeter is similarly impressive for similar reasons. There is some sensitivity on the vertical plane, and it is worth fine-tuning the loudspeaker's vertical orientation for your listening position. The wide dispersion nature of the loudspeaker, along with the distributed bass source, means that the loudspeaker is surprisingly unfussy about room positioning, or it was in my long, relatively narrow listening room, which it suited almost perfectly. But by repute it does not suit all rooms equally, and it can sound bass light in some larger environments, which perhaps will be a good excuse to add the matching subwoofer that is currently in development.

And In Conclusion...
And so the story continues, with almost boring uniformity the N800 goes around its business with aplomb, and usually with distinction, no matter what magnifying glass you may use to examine its abilities. Stereo imagery, for example, is almost ideal, with an excellent sense of scale, and the ability to sharply focus individual instruments and voices which stay put in space even when moving sideways across the loudspeaker's bows. Depth imagery is well painted both in front and behind the plane of the loudspeakers, depending on the nature of the program material, and dependent also to an extent on the proximity of the rear wall.

And that's the story of the Nautilus 800, an unusually refined and articulate high end, wide bandwidth loudspeaker suitable for use over a wide volume range, and in most rooms, though some bass level (not depth) reinforcement may be felt desirable in some surroundings. First class stereo imagery is part of the package too, and from experience I know that this holds up well in a multichannel environment with other matching Nautilus designs, though as already noted the subwoofer is still on the pending list. Bottom line, if you're interested in a genuinely high end moving coil loudspeaker, you owe it to yourself to include this one in your decision making process.

Specifications
Type: Three-way vented-box system free standing loudspeaker

Drivers: Two 10" paper/Kevlar cone bass units, one 6in woven Kevlar cone midrange unit, and one 1" metal dome high-frequency unit

Dispersion: Within 2dB Of Response On Reference Axis:
Horizontal: over 60° arc
Vertical: over 10° arc

Harmonic Distortion 2^nd And 3^rd Harmonics (90dB, 1m):
<1.0% 45Hz - 20kHz
<0.5% 50Hz - 20kHz

Frequency Response: 25Hz to 50kHz (-6dB), 32Hz to 42kHz (-3dB)

Sensitivity: 91dB, 2.83V @1m

Impedance: 8 ohms nominal, 3 ohms minimum

Crossover Frequencies: 350Hz and 4kHz

Power Handling: 1,000 watts unclipped

Dimensions: 47.1 x 17.7 x 25.4 (HxWxD in inches)

Net Weight: 275 lb. each

Cabinet finishes - Cabinet: black ash, cherrywood or red stained cherrywood real wood veneers

Accessories: carpet piercing spikes

Price: $16,000

Company Information
Bowers & Wilkins
Voice: (800) 370-3740
Website: www.Bowers-Wilkins.com