Specifications

GENERAL INFORMATION ON THE VARIOUS METHODS OF INSTALLATION
93
max 15 mt
H 2√3 mt
max 30 mt
15 mt
15 mt
Forsounddistribution
incorridors,tunnels,
passengerplatformsin
railwayorunderground
railwaystations,horn
loudspeakersare
used,suitedforvocal
reproduction,andhigher
qualityloudspeakers
called“soundprojectors”.
Inallcasesthese
loudspeakersmustbe
installedatamaximum
distanceof15metresfrom
oneanother,mounted
allinthesamedirection
andinobservance
ofthephaseofeach
loudspeaker.Alternatively
bi-directionalversionsof
theseloudspeakerscan
beconsidered,positioned
atmax.30metresfrom
oneanotherandagain
inobservanceofthe
connectionphase.(see
gure6)
DEGREES OF PROTECTION
Thecharacteristicsof
aproductintermsof
itsresistancetothe
penetrationofsolid
objectsandliquidsis
indicatedbythelettersIP
(InternationalProtection)
followedbytwonumbers.
Therstnumberidenties
theprotectionagainst
theingressofsolid
objects,whilethesecond
indicatesliquidpenetration
resistance,inaccordance
withENstandards60529-
CEI70-1.
IPdegreeofprotection
•Therstnumber
identiesthelevelof
protectionagainstthe
ingressofsolidobjects.
Numberfrom0to6.
•Thesecondnumber
identiesthelevelof
figure 6
protectionagainst
penetrationofliquids.
Numberfrom0to8.
FirstIPnumber:
0Notprotected
1Protectedagainstthe
ingressofsolidobjects
largerthan50mm
2Protectedagainstthe
ingressofsolidobjects
largerthan12mm
3Protectedagainstthe
ingressofsolidobjects
largerthan2.5mm
4Protectedagainstthe
ingressofsolidobjects
largerthan1mm
5Protectedagainstdust
penetration
6Totallydust-proof

SecondIPnumber:
0Notprotected
1Protectedagainst
verticallydrippingwater
2Protectedagainstwater
drippingatanangle(up
to15°fromthevertical)
3Protectedagainstrain
4Protectedagainstwater
spray
5Protectedagainstwater
jets
6Protectedagainstwaves
7Protectedagainstthe
effectsoftemporary
immersion
8Protectedagainstthe
effectsofpermanent
immersion
Constantimpedancelines
areusedaboveallinthe
caseofalownumberof
loudspeakers,placedata
minimumdistancefromthe
amplier(<20m).
Theconstantvoltage
connectionsystemoffersa
hostofadvantagesmaking
itidealforsoundsystems
ofallsizes,aboveallinthe
caseoflongdistances.
Thisconnectionsystem
requireseachloudspeaker
tobeequippedwithitsown
linetransformer,which
adaptstheimpedanceof
theloudspeaker(usually
verylow)tothemuch
higherlevelofthelineitself.
Inproportiontopower
transmitted,thecurrent
circulatingonalineat100V
isconsiderablylowerthan
thatcirculatingonwires
ofaconstantimpedance
system,andconsequently
dropsalongthelineare
lessfrequent;therefore
thecablesectioncanbe
smaller.
Thefunctionofthedevice
named“AMPLIFIER” is
to raise the signal of a
sound source,suchasa
microphone,CDplayer,
cassetterecorderoran
AM/FMtunerto a sufficient
level to pilot the transducer
“LOUDSPEAKER”.
The amplifierhasseveral
inputs,towhichthe
varioussoundsourcesare
connected.
Thesoundsourceshave
tobemixed(mixer)and
acousticallymodied
withtonecontroland
equaliserstooptimise
listeninginrelation
totheenvironment’s
characteristics.A
terminalboardisalso
ttedonoutputindicating
impedanceandvoltageto
whichtheloudspeakerline
isconnected.
Afewbasicrulesmust
alwaysbeobserved:
1. When the load is on
“constant impedance”,
this must be connected
to the relative socket.
 Forexamplealoadof4
ohmmustbeconnected
tosocket
marked4ohm,andso
on.Thepowerthatthe
loadcanwithstandmust
alwaysbegreaterthan
theamplier’srated
power.
 For example in the case
of a load of 100 Watt, the
amplifier must have a
power equal to or less
than 100 Watt.
2. When the load is at
“constant voltage”, this
must be connected to
the sockets indicating
output at constant
voltage -50-70 or 100
Volt; the power that the
load can withstand must
always be less than or
equal to the amplifier
rated power. For
example a load of 100
Watt, the amplifier must
have a power equal to or
greater than 100 Watt.
To calculate the value of
the amplifier power, simply
add together the power
of each loudspeaker, in
the case of a “constant
voltage” system.
However, on a constant
impedance system,
the load must have an
equivalent impedance
(series/parallel) equal to or
greater than the minimum
value indicated on the
amplifier output.
Theloudspeakerpower
supplylines,withno
connectedattenuator,must
bewith2sheathedwires;
cableswith3sheathed
wiresarerequiredin
thecaseoflinesusing
attenuatorswhichcanbe
disabledifanemergencyis
activated.Adequatewire
sectionsarerequired:1.5
mm2forlinesupto500
Wattpower
2.5mm2forlineswith
powerover500Watt.The
followinggeneralstandards
mustalsobeobserved:
• Neveruseasinglecable
(lead)forloudspeaker
connections:thiswould
causedisturbance
producingaloud“HUM”
• Neveruseshielded
cablesforthe
loudspeaker
connections:thiswould
causeseriousdamageto
thepowerunits.