Bowers & Wilkins DM630 - Manual (Page 2)

I N T R O D U C T I O N
TKc 600 Scriei of disH«l monitor loudipealren been developed from B&Wi hishly successful 500 Sefiei end
incorporates many new features to give you, the user, improved perfomwirsec
B&W maintains one of the firvest acoustic research arsd development facilities anywhere in the world. Many years
of experience in designing loudspeakers for a variety of applications, from the home to the recording studio,
from in-wall to in-car, has been applied to give you the best quality sound for ail applications.
Extensive use is made of computer aided design throughout the development programme, includirsg Finite Element
Analysis — a technique to predict diaphragm behaviour - and Laser Interferometry — used to measure actual
vibraliorts of both diaphrajms and cabinets. In addition, 6&W has access to some of the most sensitive mcasurmg
devices availayc — the ears of the experts — both musicians and others within the recording industry who know
thcir music.
All the systems in the 8&W 600 Senes have been designed with digitally recorded music in mind. Satisfying the
extra demands of digital recording •> that the loudspeakers should be able to reproduce the finest detail over a wider
dynamic range — also benefits the reproduction of analogue recordings.
The aim of this manual Is to increase your knowledge of the speakers and, in doing so, give you greater enjoyment
from their use. Because any high quality loudspeaker is dependent both on the signals fed to it and the environment
in which it IS used, w« have devoted sectiom to each of these subjects.
6&W loudspeakers are distributed to more than 50 countries worldwide and we maintain an interrtalioisal network
of carefully chosen distributors who aim to give you, the customer, the widest possible service. If at any time
you should have any problem which your dealer cannot resolve, our distributors will be more than w^mg to assist you.
DESIGN BACKGROUND
The B a W 600 Serie» comprises thiee lystems which
vary m Size and therefore m ihee ability to reproduce the
lowest frequences Rower hancfiingahoinoeasesat you
move up the range, allowing greater maximum output
levels There aie. however, several common lealuies
The enclosures
BdW's expertise m cabir^ technology loBowing the
introduction of the Matrix Senes, coupled with
advanced laser measurements, alows the optuisisaliori
of the cabinet construction to reduce unwanted
vibrations wiibn the structure Ail the 600 Series
cabrsets we manufacluied from high dermty pwlicle
board arid inirinally braced In addition, the uie of
structural plastic bailies on lop of the wooden baffles
luither Strengthens the cabnets
The crossover networks
Sophisticated computer technology at the design stage
has enabled B«W to optimise each component m the
crossover networks Computer leslv*g dunrsg production
ensures that this optimised performance is maintair'ed
to dose tolerancct ors each sample
The drive units
High-frequency
The same fvd^equerscy urui rs common to all three
systems h uses a metal dome diaphragm to provide
resonance-ficc pniorsic meton widun the audioband.
arsd magnet« Ikiid coolmg of tfic voice coil to irKrcase
power harsdlmg and 'educe compression (the dJkng
of the sound at high levek when heating of the voice
coil reduces the semiiiviiy of the unit)
Midrange/low-frequency
DM620 A sin^ f^- 200mm (8ir0 midrange/low-
frequerscy umt with a 'emforced polypropylene
diaphragm n used The 3!(nm (12ns) vo«e co4 it wound
on a Kapaon brmer with higbiempeiature epoxy
adhesives to emure hi^ power Kandkr>g The umi is
coupled to a 200nsm (8m) passive ladialor with long-
throw capabkty to reinlorce the lowesi octaves
DM630 Two idmteal drive umtt of t<miUr spec^ea-
tion to that used in the DM620 are employed m a
portedreilex endosiae Theuseoliwolow liequency
units leducet the excsnsion requued to reproduce
the lowest fiequencies, leading to lowei distortion
Power handling is also irscreased The lowe* umi is
progresswely rolled oH above 400Hr to mwntam good
veilicai
dispeison at md-Irequencies
DM640 The ported reflex ersctosuie houses two
200mm (8in) Cobe* diaphragm low-hequency units
wired m parallel, crosung over to a sepwate m^lrartge
unit at 300Hz This I60mm (6 5in) driver uses a
sophfsteatcd woven Kevlar duphragn with a cnt<al
damping layer to give the highest quality m ibs rnost
e>it<a) frequency range
UNPACKING,
INSTALLATION,
ELECTRICAL CONNECTION
AND AFTERCARE
Unpackins
We sugg^t that. alter unpackiog your loudspejke>s.
you shouid relaei ihe paclmg m case U ■$ necessary to
transpon them at a latei date The cartons corstam;
(a) One BaW DM620/630/640 loudspeaker
(b) One accessryy pack coniamng eme ahematve po»t
and one blantung^ff p^te (except DM620)
And in one cartón only
Ce) One сору of this user manual
Installation
BaW 600 Senes loudspeeker systems are designed to
be lk>oi standing The best balance of sound is acbxrved
when the kslenen' ears we wiihm ^ 5*^ of the refeterKe
axis m the vettical plane (see specifications for the
definition of reference axn). This equates to a vert<al
distance of d: 260mm 0O-3ir\) at a typical listenirsg
distance o! 3m (tOft) It ■! it necessaty to laive the system
from the door, your dealer wJI be able to advise you
on suitabe rigid stands
OM630 and DM640 are sup(^«d with a сЬснсе of twq
dilferent length ports arsd a blankmg4>fl plate which
enable you to taJer the bass response of ih< systems
(see Intervfsg room sectio»s) They aie supplied with
the longer of the two bayonet- fixed ports fitted into
the rear of г1ч enclosure The level ol bass may be
mcieased by replacing this with the shorter port,
or reduced by fitting the blarUcing-off plate
Electrical connection
All corsnectiorsi should be made with the amp'«liet
switched off. Each soeaker n provided with two pairs
of gold-prated terminals at iHe tear of tKc cabnet.
The lower pair connects the low-frequency units arsd
the uppei pan the htgh-fiequency umis (midrange and
hgh-hequen<y units m the case of OM640) The two
paas of lermirsais a'r connected togrthei by gold plated
Inks, and e'ther oai» may be used to connect the system
to the powet ans^rfier The positive (-r/red) terrnmal
of the dmol.fier should be conrsecled to a poufive
terminal on the loudspeaker (marked * '* ' with a red
bartd) The termirsals wJI accept bare waes o< 4mm
(0 >6n) banana plugs
With good qualty anolery equpmenL die reproduebors
of kjw lcvel detail can be Knproved by b-wwing your
loudspeakeis (separate cables from a common power
ampUtrr output to each paa of lentiirsah), svhich reduces
interaction between the separate sections of the crosv
over A further rclirremersi is bempUicaiion (each una
led from a separate power amplifier). In both cases
the terminal Units should be removed after temovmg the
lower termirsal caps arsd loosening the upper ones
ft is important to observe the certeci polarity when
conrsectusg a sleieo paa of loudspeakers ^№oлg
connections to one eharsnH can result m a loss of
bass and an mabrkty to locus a correct stereo image
Reversal of the polarity to one loudspeaker wiH restore
the Situation
It IS good praci<« to keep the conrsectmg leads between
power amplf «Г end the loudspeakers as short as possbb
Use heavy gauge wue to keep the DC resrstance to a
miOimuiTi. preferably below 0.2O (out and back)
Excessive usductarKe m the cable can lead to a lowering
of extieme high frequencies, whihi excessive capaci
tance can cause mslablKy in certam power amplifiers
Vov dealer wiH advtse you on the most suitable cable
lot youi needs
Aftercare
The cabaset should be treated as any rsoimal p*ece of
fum-tme U you use an aerosol deaner. spray onto a doth
arsd keep it away from the Irorst of the loudspeaker
especialy the grille cloth and drive units, tf you need to
dean the gi<8e, fvq remove the frame by gasping the
Outer edges neat the corrsers arsd genaly puQing away
horn the Cibtset The matenj may then bebushed with
a rsormal clothes bnnh or pmilat. Please asqd touching
the dnve unilSr especially the high-hrquerscy unit,
as damage could result
AMPLIFIER,
CONTROL UNIT
AND SOURCE EQUIPMENT
Tbe power amplifier
The reconvisersiitd iitratt of power output ior the dnvirsg
ampUer are givers its the speofcalion Howtvn n gymg
these limits it should also be staled that ampUiei power
Output reouitririeni IS an almost unpossble figure lor
the loudspeaker nsanufKlurer to specify flwJIdepersd
emaely upon tfse type of mus< reproduced, site ol
listening room and sound level required It n always
beltei to have an ampLli<> with high power output
as tfhs allows the proper reproduction ol tran>«nts.
whereas if the ampUiei output n too low ckpptng can
occur dunrsg h«gh peak level tramienis Apart from
cauung audble dniortion, ckppmg results m a rdalivc
eserease m the power fed to the h*gh-hequn>cy smit.
With the possibJily of thermal damage
The control unrt
The control umt - although it deals with snsall voltages
rather than Urge currents as m the case ol the power
amplifier - n an equa^ aitical part ol your kstenmg
chain Choose with care, m the knowledge that the
ultimate tcu lor aud« components is aitical ksterung
At BsW's rescards department ihcie aie many diiieieni
combirsations of control umts. ampUiets and source
componersts Such as analogsie/CD players, tuners, etc
h IS our experience that each umt (to say rsotbrsg of dse
rruerconnectmg cable) rs a wiable. arsd the Imal kuen
mg cham n a combesalion of variables wh<h should
be carefuVy kstcoed to before makmg a Imai choer