LightSpeed Technologies 780iR User manual










TableofContents
LES780iRInfraredClassroomAmplificationSystem:
Overview
LES780iRSystemComponents
SystemInstallation:
1.Unpacking
 2.Location
 3.Speaker(s)
 4.Receiver/Amplifier
5.IRSensorPlacement
  a.SuspendedCeilingMount
  b.WallorSolidCeilingMount
 6.LightMicMicrophone/Transmitter
 7.Testing
FrontPanelControls
RearPanelControls
SystemOperation:
PoweringtheLES780iR
LT-70LightMicMicrophone/Transmitter:
ControlsandConnections
ChargingtheLightMic
OperatingtheLightMic
AdjustingVolume
Operatingtwomicrophone/transmitterssimultaneously
OptionalHM-70HandheldMicrophone/Transmitter:
HM-70Overview
HM-70Controls
HM-70OperatingInstructions:
 Charging
 Operation
 HoldingandPositioning
InputfromExternalAudioEquipment
OutputtoPersonalFMTransmitter
SpeakerControl
TurningSpeakersOnandOff
ControllingtheVolumeoftheIndividualSpeakers
TipsonUsingClassroomAmplification
Five-YearLimitedWarrantytoOriginalPurchaser
OverallSystemSpecifications
TroubleshootingGuide
IndividualComponentsandOptionalAccessories
UserNotes
1
2
3
3
3
3
4
4
4
5
5
6
7
8
9
 10
11
11
11
12
12
13
13
13
14
14
14
14
14
15
15
16
17
18
19
[19]
UserNotes


serialnumber
optional
component serialnumber
LT-70LightMic
standard
components
SR-70IRSensor
PowerSupply
LES780iR
RCACables
Speakers
Wall-MountingShelf
n/a
HM-70Handheld
Microphone
TK-250Headset
Microphone

LES780iRInfraredClassroomAmplificationSystem:
Overview






















LES-780C: InfraredReceiver/Amplifier/Mixerwithbuilt-in
    charger
LES-LT70: “LightMic”RechargeableMicrophone/Transmitter
    withlavalierecord,batteriesandchargingcable
LES-HM70: HandheldMicrophone/Transmitterwithbatteries
    andchargingcable
BA-NH1:RechargeableAABattery(NickelMetalHydride)
AC-TCC7:ChargingCableforLT-70andHM-70tobeused
    with705iR
AC-LTCB:LavalierecordforLT-70
PS-24V-2.5:PowerSupply/BatteryChargerfor780iR
IR-SR70:InfraredSensorwithwallorceilingmountingbracket
MC-TK250LTM:OptionalNoise-cancelingHeadsetMicrophoneto 
    beusedwithLT-70
AC-AUDIOCABLE-4 RCACableKitforinputofaudiointotheLES780iR
CA-MMC3535:AudioPatchCable(3.5mmmonoto3.5mmmono)
CA-MMC2535:AudioPatchCable(2.5mmmonoto3.5mmmono)
SPEAKERS:ContactLightSPEEDat800.732.8999for
    loudspeakerinformation
  
IndividualComponentsandOptionalAccessories
[1] [18]

LES780iRClassroomAmplificationSystemComponents:
PowerSupply
SR-70InfraredSensorCable 

SR-70InfraredSensor
Various speakers are available and are
typically shipped in a separate box with
plenum-rated speaker wire.
RCACables
Speaker(s)
LES780iRReceiver/Amplifier
TroubleshootingGuide
Please go through this checklist before calling
LightSPEED Service Department.
BatteryCheck:
   
  
  
  
   
  
  
  
  
  
  
  
  
HearingStaticorBuzzing:
  
  
  
  
   
  
LowVolume:
  
  
  
  
  
SoundFadesInandOut
(DropOut):
   
   
  
NoSoundFromSpeaker:
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  

LT-70LightMic™
Microphone/Transmitter
[2]
[17]

SystemInstallation
1.UnpackingYourSystem
   
  
   
   
  
  
  
  
  
2.Location
Before installing the system, take time
to consider the placement of your
components.
   
   
   
   
  
   
  
  
   
   
  
  
  
  
  
   
  
  
  
  
   
  
3.Speaker(s)
  
   
  
   
  
  
  
4.Receiver/Amplifier
  
  
   
   
   
  
  
   
   
  
   
  
   
  
  
  
   
   
  
  
OverallSystemSpecifications:
CarrierFrequencies(IR) 2.06/2.54MHz
FrequencyStability +/‒3%
MaximumDeviation +/‒50kHz
DynamicRange >80dB
Signal-to-NoiseRatio >90dB
FrequencyResponse 40Hz-20kHz(‒3dB)
ReceiverSpecifications:
ReceiverType Superheterodyne
ReceiverSensitivity 6µVfor60dBS/N(>25dBuV)
ImageandSpuriousRejection >40dB
ReceptionSelectivity 40kHz
Squelching Threshold3.2µV
AmplifierSpecifications:
PowerOutput(SystemTotal) 12Wperchannel(72W)
TotalHarmonicDistortion <1%@20W
SpeakerLoadImpedance 4Ohms
PowerSupply(ULListed) 24V/2.5A
Dimensions 18x9x3(HxWxDinches)
Weight 7lbs.
Inputs:
TV/VCR RCA‒LineLevel
CD/Tape RCA‒LineLevel
Computer RCA‒LineLevel
Auxiliary RCA‒LineLevel
IRSensors(6) “F”Connector
Outputs:
AuxiliaryOutputs(2) 3.5mm
SpeakerOutputs(6) 1/4”
TransmitterSpecifications:
AudioDistortion <1%
SpuriousEmissions <30dB
Built-inMicrophone Uni-directionalElectret
BatteryPower(1-yearwarranty) 2AANiMHRechargeable
Dimensions 1.4x1x4.6(WxDxHinches)
Weight 3.04oz(w/batteries)
ExternalSensor:
Power  ByReceiverUnit
ReceptionCoverage 360º,Ceiling-mount
Cable  40ft.,Plenum-ratedCo-ax
Mounting Ceilingclip/Wallbracket
Diodes 32

[3] [16]

5.IRSensorPlacement










a.SuspendedCeilingMount
  
  
  
  
  
  
  
  
  
  
  
  
  
  
   
  
  
  
  
   
  
[note:]
e LightMic rechargeable batteries come
installed at the factory. ere is enough charge
within the LightMic batteries to adequately
test the system during initial setup. However,
the batteries need to be charged for 8 or more
hours before regular use for optimum battery
life.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
b.WallorSolidCeilingMount
[4]
TipsonUsingClassroom
Amplification
ese helpful suggestions are provided
to maximize the successful use of
your new LES 780iR Infrared Classroom
Amplification System.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
  
 
 
 
 
Five-YearLimitedWarranty
toOriginalPurchaser






















Donotattempttochargealkaline
batteriestheywilloverheatandexpand,
creatingasignificanthazardanddamaging
thetransmitter.(Thistypeofdamgeisnot
coveredunderwarranty.)
[caution!]
[15]

[14]
InputfromExternal
AudioEquipment




 
 
 
 
 
 
 
 
 
OutputtoPersonal
FMTransmitter

 
 
 
 
 
 
 
 

 
  
 
SpeakerControl














TurningSpeakersOnandOff

 
 

 
 

 
  
 
 
 
 
ControllingtheVolumeof
theIndividualSpeakers








  
 

 

 
  
 
Turning speaker volume too high can result in
feedback when walking under speaker.
6.LightMicMicrophone/
Transmitter

 
 

  
  
   
  
  
   
   
  
  
7.Testing
 
 
 
 
 
  
  
  
  
  
   
  
  
[note:]
e system can generate feedback (a squealing
or howling sound) if there is too much volume
or the equalization (EQ) levels are incor-
rectly set. Adjust the three EQ level knobs if
necessary to eliminate feedback and to obtain
a natural sound.
  
  
  
  
  
   
  
[5]

FrontPanelControls

 
 
 
 
 

 
 
 
 

 
 
 
  
 
 
 
 
 
 
 

 
 
 
 
 

 
 
  
  
 
12
3
4
6
7
5
HM-70OperatingInstructions
Charging
Rechargeable batteries are pre-installed.
  
 

  
 
 
 
 
 
 
 
 
 
 
 
NiMH batteries maintain their charge for
a full day of normal classroom use. Always
turn the HM-70 off when not in use.
Operation
e Channel A/B switch is located inside
the battery compartment. e switch is set to
Channel B at the factory.
 
  
 
 
 
 

  
 
 
 
HoldingandPositioning
 
 
 
 
 
 
 
  
 
  
 
[13] [6]

[12]

 
 
 
 
 
 
 

 
 

 
 

 
 
 
 
 

 
  
 
 
 
 
 

  
  
  
 
 
RearPanelControls
1
2
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4
5
6
7
8
9
10
11

 
 
  
 

 
 



 
  
 
 
e three frequency
equalization adjustments are factory set
for normal classroom environment.
  
  
  
HM-70Controls
 
  
 
 
 
 
  
 

 
 
 

 
 
 
 
 
 
 
[7]
OptionalHM-70Handheld
Microphone/Transmitter:
Overview





Donotattempttochargealkaline
batteriestheycanoverheatand
expand,creatingasignificanthazard
anddamagingtheLightMic.
[caution!]
(is is not covered by the warranty.)
Power/ChargeLED
Indicator
PowerSwitch
ChargingJack Battery
Compartment
ChannelSelectSwitch
GainAdjust
3
1
4
2
slidetoopen
topviewofbatterycompartment

OperatingtheLightMic
 
 
 

 
 
 
Place the lavaliere cord around your neck,
and adjust the length so the top of the
LightMic rests on the collar bone.
 
 
  
  
  
 

 
 
  
 
  
  
 
AdjustingVolume
Volume is set by adjusting the volume control
on the LES 780iR.
 


 
 
  
 
  
 
 
 

 
 
 
 
[note:]
Feedback or “squealing” may occur if the
volume is set too high. Reducing the loudness
of the speakers with the volume control
usually eliminates feedback.
Operatingtwomicrophone/
transmitterssimultaneously





  
  
 
 
 
 
 
 
 
When the LES 780iR is receiving a signal
from the microphone/transmitters:
 
 
 
 
 
 
 
  
 
 
SystemOperation:
PoweringtheLES780iR
  
  
  
 
  
  
  
  
  
 
  
Check that:
  
  
  
  
a
b
c
d
e
[11] [8]