804 Stereophile
User Manual: 804
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DIAMONDS
ARE
fOREVER
B&W’s 804 Diamond tower
ELECTRONICALLY REPRINTED FROM SEPTEMbER 2013
SUPER SPEAKERS
from $129 to
$17,500/pair:
EquipmEnt REpoRt
Description Three-way,
reflex-loaded, floorstanding
loudspeaker. Drive-units:
1" (25mm) diamond-dome
tweeter, 6" (150mm) FST
woven-Kevlar midrange cone,
two 6.5" (165mm) Rohacell-
cone woofers. Crossover
frequencies: 350Hz, 4kHz.
Frequency range: –6dB at
30Hz and 33kHz. Frequency
response: 38Hz–28kHz,
±3dB, on reference axis.
Dispersion: within 2dB of
on-axis response over 60°
arc (horizontal) and 10°
arc (vertical). Sensitivity:
90dB/2.83V/m. Harmonic
distortion (second and
third harmonics, 90dB,
1m): <1.0%, 90Hz–100kHz;
<0.5%, 120Hz–100kHz.
Impedance: 8 ohms
nominal, 3 ohms minimum.
Recommended amplification:
50–200W into 8 ohms,
unclipped program.
Maximum recommended
cable impedance: 0.1 ohm.
Dimensions 39.8" (1020mm)
H by 9.3" (238mm) W by
13.7" (351mm) D. Weight:
59.4 lbs (27kg).
Finishes Rosenut, Cherry,
Piano Gloss Black.
Serial numbers of units
reviewed: 009625,
009626 (listening); 009176
(measuring).
Price $7500/pair.
Approximate number of
dealers: 275.
Manufacturer
Bowers & Wilkins,
Dale Road, Worthing,
West Sussex BN11 2BH,
England, UK.
Tel: (44) (0)800-232-1513.
www.bowers-wilkins.co.uk.
US distributor:
B&W Group North America,
54 Concord Street,
North Reading, MA 01864.
Tel: (978) 664-2870.
Fax: (978) 664-4109.
www.bowers-wilkins.com.
specifications
I
don’t think that the Bowers and Wilkins 804, in any
of its incarnation, gets its due respect. As the smallest
floorstander in B&W’s elite 800 series, it has histori-
cally been overshadowed by its larger brethren and out-
maneuvered by the smaller, stand-mounted 805. However,
the 804 Diamond is unique, and deserves special attention
for reasons I discovered when I chose the earlier 804S for
the surround channels of my 5.1-channel surround system.
The first of these reasons: The three-way 804 Diamond
takes up no more floor space than the two-way 805 while
also having two 6.5" woofers, which greatly expand its power
handling and bass extension. In fact, it was my wife who,
when I consulted her about choice and placement, asked why
one would even consider the smaller speaker when the bigger
one took up no more floor space and looked better. Second,
in the 804, the same 6" Kevlar-cone mid/woofer used in the
805 is relieved of all bass responsibilities and works purely in
the midrange, as it does in the 800 Diamond.
The third reason—perhaps a corollary of the second—is
that dedicating the Kevlar driver to the midrange means that
it can be used with B&W’s proprietary Fixed Suspension
Transducer (FST) technology, which was designed to better
control and define the breakup patterns of relatively nonrigid
diaphragms. The use of Kevlar in the 805’s mid/woofer
demands a more traditional surround that imposes the un-
controlled radial breakup patterns that the use of a Kevlar
diaphragm was intended to avoid. Note, also, that B&W uses
diaphragms of Rohacell, which is stiffer than Kevlar, in the
woofers (ie, not mid/woofers) of all its 800-series models,
including the 804.
Finally, although the 804 Diamond is not endowed with
B&W’s iconic Marlan head, as in the 800 Diamond (see
www.stereophile.com/content/bampw-800-diamond-loud-
speaker), the 804’s midrange driver is still enclosed in an
internally tapered enclosure, and scores over the larger but
similarly configured 803 Diamond in having a narrower
cabinet, which, potentially, would not have as great an
impact on midrange dispersion. It might also be effective
in minimizing the kink in the horizontal off-axis radiation
pattern that John Atkinson has discovered in the transition
from the woofers to the midrange drivers of the Marlan-
topped 802 and 800 Diamonds.
Arrival
The 804 Diamonds arrived in substantial packaging that
lacked the forklift-accessible plinths needed for the 800 Dia-
monds. I was grateful for the unpacking instructions printed
on the outside of the box; I was able to unpack and set them
up with little effort and no assistance. Both spikes (for carpet)
and plastic feet (for hardwood floors) are provided. I chose
the latter. The slim, graceful cabinet is oval in cross section,
except for the flat front panel; my review samples were
finished in Rosenut veneer. (Cherry and Piano Gloss Black
are also available.) A black front grille attaches magnetically—
Kalman Rubinson
Bowers & Wilkins 804 Diamond
loudspeaker
Eric SwanSon
Fig.1 Bowers & Wilkins 804 Diamond, electrical
impedance (solid) and phase (dashed) (2 ohms/
vertical div.).
Fig.2 Bowers & Wilkins 804 Diamond, cumula-
tive spectral-decay plot calculated from output of
accelerometer fastened to center of side panel level
with upper woofer (MLS driving voltage to speaker,
7.55V; measurement bandwidth, 2kHz).
The 804 Diamond’s tweeter is loaded with a transmission line.
BOWERS & WILKINS 804 DIAMOND LOUDSPEAKER
I
used DRA Labs’ MLSSA sys-
tem and a calibrated DPA 4006
microphone to measure the
Bowers & Wilkins 804 Diamond’s
frequency response in the farfield, and
an Earthworks QTC-40 for the nearfield
responses, the latter’s 1⁄4" capsule of-
fering no significant acoustic obstacle
to the outputs of the small diaphragms.
Before performing any measurements,
I removed the plastic disc from the rear
of the tube that loads the midrange
unit, as instructed in the manual.
My estimate of the 804 Diamond’s
voltage sensitivity was 89.3dB(B)/
2.83V/m. While this is slightly lower
than the specified 90dB, it is still usefully
higher than average. The plot of the 804
Diamond’s impedance magnitude and
phase against frequency is shown in fig.1.
The speaker is a moderately difficult
load for the partnering amplifier to drive.
Not only does its impedance reach a
minimum value of 3 ohms at 108Hz, there
is a combination of 4.5 ohms and a 53°
capacitive phase angle at 72Hz, and the
impedance remains below 4 ohms for
much of the midrange and the top octave.
The traces in fig.1 are free from the
small discontinuities that would sug-
gest the presence of resonances in the
speaker cabinet’s walls. Nevertheless,
investigating the enclosure’s behavior
with a simple plastic-tape accelerome-
ter, I found a strong resonance at 309Hz
on the side walls level with the upper
woofer (fig.2), with a lower-level mode
at a slightly lower frequency. However,
as Kal Rubinson didn’t comment on any
congestion in the midrange that might
be laid at the feet of this resonance,
it’s likely that the affected area, hence
the audibility, is relatively small. The
sidewall in the vicinity of the midrange
unit was dead as a doornail.
The saddle centered on 31Hz in the im-
pedance-magnitude trace in fig.1 suggests
that this is the tuning frequency of the
flared port on the front baffle. Indeed, the
port’s output, measured in the nearfield,
peaks between 22 and 44Hz, with a
smooth rolloff above that region unbroken
by any midrange resonances (fig.3, red
trace). To my surprise, however, the two
woofers behaved differently in the bass:
while the upper woofer (green trace) had
a minimum-motion notch at 30Hz, the
lower woofer’s (blue) lay at 26Hz. (For
clarity, the levels of the two woofers are
each raised by 6dB in this graph.) The
crossover to the midrange driver (black
trace) appears to lie just below 400Hz,
big 800Ds out of the way—that I had just replaced two very
familiar, very large speakers with a pair of small towers fresh
from the farm. Apparently, I adapted as I adjusted the setup.
The 804Ds ended up about a foot closer to each other than
where they started out, toed in by no more than 10°.
when the grille is removed, no securing devices mar the
speaker’s appearance.
On top of the cabinet, lying in a shallow niche, is B&W’s
iconic enclosure for its diamond tweeter and its tapered
tube. Below that is the yellow, woven-Kevlar diaphragm
of the FST midrange driver, which is installed through the
front panel and secured by a shaft to a compliant support
in the rear, just as the FST midranges in the 802 and 800
Diamond models. (A plastic disc must be removed from the
rear of the midrange enclosure, which opens to the speaker’s
rear, before listening.) Below that are the two Rohacell-cone
woofers and a low-turbulence port, dimpled and flared, and
similar to the one hidden on the underside of the bigger
models. Protruding from near the top of the rear of the cabinet
is the adjustable mount for the midrange; near the bottom are
two pairs of speaker binding posts of a new design that ac-
commodates easy tightening by hand. Biwiring and biamping
are thus made possible; jumpers are also provided. To meet
EU requirements, the center bore of each binding post is
occupied by a plastic plug; I removed these in order to use
cables terminated with banana plugs.
Set-up
I was able to lift and lower each 60-lb 804 Diamond into posi-
tion by using its bass port as a grip. At first, I set them up in the
precise spots just vacated by my 800 Diamonds. In these posi-
tions, the 804Ds seemed to sound somewhat thin and bright,
but some expectation bias is inevitable: I was consciously
aware, from both sight and aching muscles—I’d just moved the
measurements
Fig.3 Bowers & Wilkins 804 Diamond, acoustic crossover
on HF axis at 50", corrected for microphone response,
with nearfield responses of midrange unit (black), upper
woofer (green), lower woofer (blue), and port (red),
respectively plotted below 450Hz, 2kHz, 2kHz, 550Hz.
Fig.4 Bowers & Wilkins 804 Diamond, anechoic
response on HF axis at 50", averaged across 30°
horizontal window and corrected for microphone
response, with complex sum of nearfield responses
plotted below 300Hz.
Fig.5 Bowers & Wilkins 804 Diamond, lateral
response family at 50", normalized to response on
HF axis, from back to front: differences in response
90–5° off axis, reference response, differences in
response 5–90° off axis.
BOWERS & WILKINS 804 DIAMOND LOUDSPEAKER
measurements, continued
comparing the 804 Diamond to its 804S forebear or to its
big brother, the 800 Diamond, both of which I had on hand,
I’ll first describe the 804D’s sound as I found it, independent
of comparisons.
I listened casually to the 804 Diamonds for a couple of
weeks before sitting down to do more careful listening.
During that time they evinced good tonal balance and great
stereo center fill. FM broadcasts sounded good, with no em-
phasis of hiss with weak signals, and Internet radio sounded
fine without obvious dulling due to the limited bandwidth.
As I sat down with my favorite discs and downloads, my
expectations were rising.
The 804 Diamond was quite beyond criticism in the
treble, with clarity and fine detail. Cymbals and triangles
sizzled and tingled appropriately, but, more important, E-
string fiddling was sweet and pure. Voices, too, were lifelike,
whether solo or in chorus. One of my new favorite vocal
recordings is a 24-bit/192kHz PCM download of Marianne
Beate Kielland’s recital disc Come Away, Death (SACD/
CD, 2L 2L-064-SACD). Following a tonally convincing
introduction by pianist Sergei Osadchuk, Kielland’s silken
mezzo-soprano appeared eerily between the 804 Diamonds
with such presence that I got up to check that my (pre-
sumably) idle center speaker was, in fact, silent. The effect
expanded with multiple voices—as on Dixit Dominus, a disc
pairing Handel’s and Vivaldi’s settings of Psalm 109, with
David Bates leading La Nuova Musica (SACD/CD, Har-
monia Mundi HMU 807587): the choristers’ voices were
arrayed in space between and above the 804 Diamonds.
Comparisons can be odious
That doesn’t mean that comparisons smell bad, but mak-
ing direct comparisons can lead to various problems. In the
case of speakers, it’s all too easy to describe how one speaker
sounds different from another, but 1) that doesn’t tell us a
lot about which speaker might be better or more accurate,
and 2) a specific character of one speaker might constrain an
accurate description of another. So, although I can’t ignore
and the crossover seems to feature asym-
metrical slopes: 24dB/octave high-pass
but 18dB/octave low-pass. The woofers’
upper-frequency behavior is identical.
Higher in frequency in fig.3, the 804
Diamond’s treble response is uneven,
with a suckout evident between 1.5 and
3kHz and a peak indicated between 7
and 16kHz. Puzzled by this, I checked
the response using a different micro-
phone (a QTC-40) and a different
measurement system (Fuzzmeasure
3.0). The result was identical. I then
looked at the review my colleague
Thomas J. Norton had written for Home
Theater magazine: While the measured
response of the 804 Diamond in Tom’s
review (the red trace in the graph at
http://tinyurl.com/mjk2wwy) differed
in the fine details, the overall measured
response was broadly similar to mine.
Fig.4 shows how these individual
responses sum in the farfield. The bump
in the upper bass is primarily an artifact of
the nearfield measurement technique; as
KR found in his listening, the 804 Diamond
offers excellent low-frequency extension,
the output lying 6dB down at 28Hz.
At the other end of the audioband, the
combination of presence-region suckout
and top-octave peak persists, though the
overall trend is basically flat. The effect of
the suckout would be to make the speaker
sound somewhat laid-back, though the
upside is that the 804 Diamond would be
forgiving of too-bright recordings, which
are common. The peak is a little too high in
frequency to render the sound “steely” or
“wiry”; instead, it might just emphasize the
airiness of the recording.
The B&W’s lateral dispersion, normal-
ized to the response on the tweeter axis,
is shown in fig.5. Although the suckout at
the top of the midrange unit’s passband
deepens to the speaker’s sides, the radia-
Digital Sources Sony XA-5400ES SACD/CD player, Oppo
BDP-105 universal Blu-ray player, Mytek Stereo192-DSD DAC,
PC-based server using JRiver Media Center 18.
Preamplification Audio Research MP1 multichannel analog
preamplifier, Meridian HD621 HDMI audio processor & 861
Reference V6 digital surround controllers.
Power Amplifiers McIntosh MC303, Parasound A-31 (both
three-channel).
Loudspeakers Bowers and Wilkins 800 Diamond & 804S,
Aerial Acoustics 7T.
Cables Interconnect: van den Hul Flat 180, AudioQuest Vodka
(HDMI); Black Cat Veloce (digital); AudioQuest Cheetah
(DBS balanced). Speaker: AudioQuest Mont Blanc (DBS
biwire). AC: JPS Aluminata.
Accessories Environmental Potentials EP-2450 power
conditioner.—Kalman Rubinson
associated equipment
The twin 6.5" woofers feature Rohacell cones.
Fig.6 Bowers & Wilkins 804 Diamond, vertical
response family at 50", normalized to response on
HF axis, from back to front: differences in response
15–5° above axis, reference response, differences in
response 5–10° below axis.
Fig.7 Bowers & Wilkins 804 Diamond, step re-
sponse on HF axis at 50" (5ms time window, 30kHz
bandwidth).
Fig.8 Bowers & Wilkins 804 Diamond, cumulative
spectral-decay plot on HF axis at 50" (0.15ms
risetime).
BOWERS & WILKINS 804 DIAMOND LOUDSPEAKER
measurements, continued
touch of his fingers on the strings is easily discerned from
the rich supporting resonances of the instrument’s body.
Each repetition of the familiar theme offers another serving
of mesmerizing harmonies.
Lower-pitched male voices and
cello, however, demanded greater
scrutiny—speakers the size of the
804 Diamond often lack the true
low bass of bigger speakers. How
and where the low end rolls off
can pull the rug out from under
low voices, robbing them of weight
and warmth. I pulled out my Hans
Theesink and Leonard Cohen
discs, just to confirm that their
voices sang out with focus, depth,
and grit. More critically, Gavriel
Lipkind’s 1702 Garani cello spoke
in a single voice across its range,
from the soprano sweetness of the
A string to the baritonal warmth of
the C string, in Lipkind’s recording
of J.S. Bach’s Suites for Solo Cello
(SACD/CD, Lipkind Productions S04), indicating bass exten-
sion entirely sufficient for realistic tonal balance. It was, therefore,
no surprise that the plucked lower strings in Boccherini’s La
Musica Notturna della strade di Madrid, from the Stuttgart Chamber
Orchestra’s Die Rohre—The Tube (SACD, Tacet S 074), were
rendered with appropriately plosive effect.
Moving down the spectrum to winds and guitar, the pres-
ences, placements, and harmonic balances of those instruments
were exquisite. Stefano Grondona’s guitar in Francisco
Tarrega’s Capricho árabe, from Grondona’s La Guitarra de
Torres (CD, Divox CDX-29701), is intimately recorded—the
tion pattern is even and uniform overall—
something that always correlates with
stable and accurate stereo imaging. In
the vertical plane (fig.6), a suckout at
the upper crossover frequency of 3.9kHz
develops 10° above and 15° below the
tweeter axis. It also looks as if the flattest
treble response occurs 5° below the
tweeter axis.
This is confirmed by the 804 Dia-
mond’s step response on the tweeter axis
(fig.7), which is 40" above the floor: the
sharp up/down spike that represents the
tweeter’s output doesn’t quite smoothly
blend with the start of the midrange
unit’s slower-rising output. Moving the
microphone down by 5° would bring the
midrange unit’s output slightly forward in
time and eliminate the slight discontinu-
ity in this graph. Fig.7 also indicates that
all four drive-units are connected in the
same, positive acoustic polarity, this con-
firmed by examining the step responses
of the individual units (not shown).
Finally, the 804 Diamond’s cumulative
spectral-decay plot on the tweeter axis
(fig.8) is generally clean in the treble.
In 2004, I visited Bowers & Wilkins’
Research Center, in the village of Steyning,
West Sussex, nestling in the shadow of
England’s South Downs, north of Worth-
ing. I was impressed by both the depth
and the breadth of the engineering talent
and resources I found there. There is no
doubt in my mind that B&W’s engineers
can design a loudspeaker to have any
response they desire. That the 804
Diamond does not have a flat on-axis re-
sponse is thus a mystery. That suckout in
the presence region in fig.4, for example,
appears from fig.5 to be due to the large-
diameter midrange driver narrowing its
radiation pattern in the top octave of its
passband, despite the FST technology
that is intended to prevent that from
happening. But overall, the B&W 804
Diamond’s measured performance is
quite respectable.—John Atkinson
The 804
Diamonds’
significantly
greater bass
extension
endowed the
sound with
a natural
balance often
sacrificed by
the smaller
speakers.
Standing almost 40" tall, the 804D has a domestically friendly footprint.
Posted with permission from the September 2013 issue of Stereophile ® www.stereophile.com. Copyright 2013, Source Interlink Media, Inc. All rights reserved.
For more information on use of this content, contact Wright’s Media at 877-652-5295. 103771
BOWERS & WILKINS 804 DIAMOND LOUDSPEAKER
The two models sound similar, too, though I easily heard
the differences in an A/B comparison. There is some im-
provement of bass definition at the extreme bottom of the
audioband, the 804 Diamond offering a somewhat sharper
edge to LF transients, particularly noticeable with bass gui-
tar. There was also significantly more detail in the critical
upper midrange, around the upper crossover frequency of
4kHz, which is also in the range of the human ear’s greatest
sensitivity. B&W’s use of gold-silver-oil Mundorf capacitors
in the HF crossover filter and the Diamond tweeter—which
were used only in the 800 Diamond in the previous genera-
tion of models—is probably paying great dividends here.
Compared with other speakers that have occupied this
room, the 804 Diamond sounded like a nimbler version of
the 800 Diamond ($24,000/pair), or a compact version of
the Aerial Acoustics 7T ($9850/pair, see www.stereophile.
com/content/aerial-acoustics-model-7t-loudspeaker). In
the first case, a comparison of the specs (and ignoring their
differences in size and weight) revealed that the 800 and
804 Diamonds differ in only two performance parameters:
low-frequency extension/THD and maximum power
handling. So, granting the very real sonic differences at the
low end of the audioband, I found that the 804 Diamonds
produced a closer, more intimate sound in my 26' by 15'
room, perhaps due to the effects of their narrower cabinets on
midrange radiation and room interaction. The Aerial
7T’s bass capabilities, too, are greater than
the 804 Diamond’s, with the latter’s
smaller drivers and enclosure, while
the Aerial’s midrange is equally
detailed and a bit smoother. The
treble was a toss-up. Overall, the
slightly bigger and more costly 7T
differs only slightly from the 804
Diamond, and its advantages would
not be substantial in smaller rooms.
Conclusions
In general, I had become so accept-
ing of the generous size and sound
of the bigger, pricier speakers I’ve
been using that I was surprised by
how satisfying the 804 Diamonds
were. I should not have been—for
$7500/pair, one should expect
superb performance across the
board. B&W has trickled down
their unique technologies to the
entire 800 Diamond range, and
the 804 Diamonds incorporate all
the most important ones. In fact,
with the 804 Diamonds replacing
the 800 Diamonds for the front
left and right channels—a third 800
Diamond remaining for the center
channel, and 804Ses as surrounds—
they gave up little in multichannel
performance. And the 804
Diamonds sounded excellent as a
stereo pair, leaving me in no rush to
relegate them to surround duties.
For the money, I don’t feel you can
do much better—different, maybe,
but for making music, not better. n
At the very bottom, the 804 Diamonds were capable of
playing everything creditably, if not imposingly. I noticed
this first when playing a 24/96 download of “Malena,”
my favorite track from Será Una Noche (M•A Recordings
M052A). It was delightfully atmospheric, as always, but the
rhythmic percussion didn’t
seem to anchor the tempo
as solidly as I had expected.
The footfalls of the Cosmic
Hippo, as depicted by Victor
Wooten’s bass in the title
track of Béla Fleck’s Flight
of the Cosmic Hippo (CD,
Warner Bros. 26562-2), were
weighty but less than thud-
ding, and the heartbeats in
Pink Floyd’s Dark Side of the
Moon (SACD/CD, Capitol
CDP 5 82136 2) were au-
dible but not palpable.
Still, the bass was certainly
good. Had I not savored these
tracks before through bigger
speakers—such as the 800
Diamonds—I probably would not have noticed anything
missing. Those who delight in the open soundstage and
pinpoint imaging of minimonitors will find that in spades
with the 804 Diamonds, whose significantly greater bass
extension endowed the sound with a natural balance
often sacrificed by the smaller speakers in the pursuit
of those other qualities. As a result, the lack of really
deep, powerful bass from the 804 Diamonds is, to
me, a minor issue overall. I found that, unlike stand-
mounted minimonitors, the 804Ds could deliver
a full orchestra of appropriate balance and size, as
was demonstrated when I played Dmitri Kitayenko
and the Cologne Gürzenich Orchestra’s recording
of Tchaikovsky’s monumental Manfred Symphony
(SACD/CD, Oehms Classics OC665). And if you
demand that the impressive bass-drum whacks also hit
you in the chest, or that the organ in the final move-
ment also shake your room . . . get a subwoofer.
Audible differences
I began this review by saying that B&W’s 804
models have not gotten as much attention as they
deserve. I, too, was guilty of this. When, a decade
ago, I transformed my main system from two to
5.1 channels, I chose the B&W 804S for surround
duties without ever having heard them as a stereo
pair—and there they sat in the background ever since,
until I pulled them out to compare them with their
successors. With the 804Ses ($4000/pair when last
available) plonked down next to the 804 Diamonds
($7500/pair), I often found it difficult to distinguish
between them by eye or ear, but there were differ-
ences. Other than the 804D being three pounds
lighter than the 804S, B&W’s specifications for the
two are identical. Careful study reveals that the 804D
sports a silver ring around its now gloss-black tweeter
housing, has mushroom-shaped terminal knobs, and
replaces the grille’s tabs with magnetic attachments.
I had become so
accepting of the
generous size
and sound of the
bigger, pricier
speakers I’ve
been using that
I was surprised
by how
satisfying the
804 Diamonds
were.
