Specifications

GENERAL INFORMATION ON THE VARIOUS METHODS OF INSTALLATION
92
FBT: EXCELLENCE WITH A
VAST SELECTION
FBToffersavastand
comprehensiverange
ofspeakerstomeetall
soundrequirementsand
applications.Specically
designedtoenablesimple
andsafeinstallation,witha
modernandeye-catching
design,theseproductsare
theidealchoicetosolveall
ambientsounddistribution
requirements.
Allproductlines,
fromrecessedceiling
loudspeakersinpaint-
nishedmetalorinplastic
withdualconeorcoaxial
loudspeakers,speakers
constructedusingre-
resistantmaterials,IP
55-56-68weatherproof
elements,speakers
designedforcleanrooms
orspecialproduction
departments,tothe
industrialorentertainment
soundmodels,
havebeendesigned
accordingtothelatest
electro-acoustical
parameters.
Theresultisabsolute
excellence;perfect
musicreproductionand
optimalvoiceclarityand
speechdelity.Special
attentionhasbeenpaid
tothesimplicationand
reductionintimerequired
forinstallationand
networkconnectionsof
thepowercables,thanks
toaspecialaccessorykit
suppliedasstandard.
The basic principles of
effective surface mount
ceiling loudspeaker
installation
Therstpriorityofahigh
qualitysoundreproduction
systemisthatofproviding
listenerswithsound
informationatanacoustic
levelthatishigherthan
anypossiblebackground
noise.Thesystemmust
simultaneouslyassure
averywidefrequency
bandandthemaximum
intelligibility.Itshouldalso
guaranteeaatfrequency
responseanduniform
soundpressuretogive
optimumlisteningpleasure
andclarity.Tomeet
theserequirements,the
hypotheticalidealsolution
wouldbetoplaceeach
soundsourceatanequal
distancefromallpossible
listeningpoints.
CEILING APPLICATION
Inenvironmentsoffering
suitableheight,thisideal
referencestandardcan
beapproximatedby
usingloudspeakerswith
verywideresponseand
dispersionanglesthat
remainunchangedat
differentfrequencies,
arrangedinaceilingor
showertypeconguration.
Thisgivesthefollowing
benets:
1- Maximumsound
distributionuniformity
2- Maximumspeech
intelligibility
3- Constantqualityof
musicreproduction
4- Reducedpresence
ofreverberationand
stationarywavesinthe
environment
5- Soundsourceremains
ataconstantdistance
fromthelistening
position
6- Amplesoundenergy
alsoatthelowestlevel
Oncetherequiredtype
ofloudspeakerhas
beenchosen,andthe
characteristicparameters
considered(particularly
therelationshipbetween
thedispersionangle
andtheroomsurface
area),thenumberof
unitsneededtoobtain
constantanduniform
sounddiffusioncanbe
easilycalculated.The
numberofloudspeakersis
calculatedbydividingthe
oorareainsquaremetres
bytheareaofcoverage
ofeachloudspeakeron
thelisteningplane.Figure
1clearlyillustratesthe
aboveconcept.
2 x 2
ZONA
D'OMBRA
(H-1,5 mt)
1,5 mt
H
α α
4√5 mt
5√6 mt
12 mt
2√2,5 mt
8√10 mt
5√6 mt
5√6 mt
24 mt
2√2,5 mt
figure 1
figure 2
figure 3
WALL APPLICATIONS
Ifthearchitectural
featuresoftheroomare
notcompatiblewitha
ceilingcongurationor
ifa“wall”applicationis
preferred,itisessentialto
observeafewbasicrules
toobtainthebestpossible
sounddistribution.In
ordertomaintainthe
listeningpointinsidethe
directsignalarea,both
surfacemountedand
externalloudspeakers,
withpowerfrom6to20
Watt,shouldbeinstalled
ataheightofbetween2
and2.5m.Themaximum
distancebetweenadjacent
loudspeakersmustbeno
morethan5/6metresalong
thelengthoftheroom,
whichshouldbenowider
than4/5metres.Forwider
rooms,e.g.about8-10
metres,itisrecommended
toinstallloudspeakersin
analternatedpatternalong
boththeopposingwallsin
suchawayastoprovide
adequatecoverageand
maintainsoundpressure
atthemostconstant
possiblelevelinthearea
inquestion(seegures2
and3).
Aquick and approximate
calculationcanbemade
ofdistanced,which
separatesthecentresof
twoloudspeakers,when
theangleofemissionA
andheightoftheceilingH
isknown:d=2*(H-1)*B
whereHistheheightof
theceilingexpressedin
metres,constant1isthe
heightofthelistening
surfaceofaseatedperson
andBisthetangentof
A/2.Fromtheabovedata,
itisevidentthatforthe
sameceilingheightH,
loudspeakerswithwider
dispersionanglesoffera
largersounddiffusionarea
andthereforeasmaller
numberofspeakersare
effectivelyneeded.
Figure4showsthesurface
areacoveredbythesound
signalwithrelativedark
zones,andgure5witha
differentgridandgreater
numberofloudspeakers
(50%)guarantees
maximumuniformity.
Angle of Coefficient d with d with d with d with
loudspeaker B H=3m H=3.5m H=4m H=4.5m
emission
80 0,84 3,36 4,2 5,04 5,88
90 1,00 4 5 6 7
100 1,19 4,76 5,95 7,14 8,33
110 1,43 5,72 7,15 8,58 10,01
120 1,73 6,92 8,65 10,38 12,11
130 2,14 8,56 10,7 12,84 14,98
figure 4
Layout of loudspeakers for 80% coverage
figure 5
Layout of loudspeakers for 100% coverage