LightSpeed Technologies Stereo Amplifier 780iR User Manual

LES 780iR INFRARED CLASSROOM  
AMPLIFICATION SYSTEM  
U S E R ’ S M A N U A L  
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LES 780iR Infrared Classroom Amplification System:  
Overview  
e LES 780iR Infrared Classroom  
e LT-70 LightMic is a wireless, pendent-  
Amplification System includes the LES  
780iR receiver/amplifier, LT-70 Light Mic™  
microphone/transmitter, SR-70 infrared  
sensor and speaker package. is system  
allows teachers to speak at a normal conver-  
sational level while being heard clearly by  
every student in the classroom.  
style microphone/transmitter. is two-  
channel, rechargeable microphone  
is clipped to a lavaliere cord and worn  
around the neck or held like a  
standard microphone.  
e LES 780iR is a two-channel receiver/  
amplifier that allows the use of two micro-  
phones and up to four audio input sources.  
In addition, up to six speakers can be con-  
nected to the LES 780iR, ensuring that no  
matter the size or shape of the room, every  
child hears every word—every time.  
[1]  
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LES 780iR Classroom Amplification System Components:  
LES 780iR Receiver/Amplifier  
Power Supply  
RCA Cables  
Speaker(s)  
LT-70 LightMic  
Microphone/Transmitter  
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.  
[2]  
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System Installation  
1. Unpacking Your System  
3. Speaker(s)  
Ensure that you have received all of  
the components to your system.  
Locate the speaker installation  
instructions packed with your  
speaker(s).  
Locate the speaker installation  
instruction sheet that is packed with  
your speakers.  
Follow instructions and mount  
speakers(s).  
Keep ALL packaging materials.  
If the system must be returned, it  
will be quick, convenient and  
undamaged.  
Return to the LES 780iR manual to  
complete the set up of your system.  
4. Receiver/Amplifier  
Place the LES 780iR on a flat surface  
like a bookcase or countertop.  
2. Location  
Before installing the system, take time  
to consider the placement of your  
components.  
Ensure that the A VOLUME  
and B VOLUME knobs are  
turned all the way down (fully  
counter-clockwise) and the POWER  
switch is the OFF position.  
Infrared (IR) Sensor: Consider areas  
of dark color in the room as they  
reflect less infrared light. Sensor  
mounting locations should be closer  
to dark areas to improve reception.  
Connect the speaker wire(s) to the  
appropriate 1/4” SPEAKER OUT  
jacks on the back of the LES 780iR.  
(Refer to your speaker instructions  
for additional information.)  
Receiver: Place on flat surface close  
to standard electrical outlet.  
Speaker: Refer to the speaker  
installation sheet that is included  
with the speaker for placement  
needs.  
Plug the power cord into a standard  
110 V electrical outlet and attach the  
other end into the DC POWER jack  
on the back of the LES 780iR.  
Speaker Wire and Sensor Wire:  
Plenum wire is included for  
Switch the power on the front  
panel to the ON position. e red  
power indicator on the switch  
will light.  
each. Ensure the wire length will  
cover the area from where you hang  
the sensor and speaker(s) to where  
you place the receiver. It’s optimal to  
route wire overhead (above ceiling  
tiles) if possible. In addition, wire  
can be routed down the wall and  
around the room perimeter secured  
with heavy staples or wire raceway.  
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b. Wall or Solid Ceiling Mount  
5. IR Sensor Placement  
Sensor location is very important for  
optimum performance of the LES 780iR  
Classroom Amplification System. Place  
the sensor in a temporary location and test  
the system (Step 7 below) before choosing  
a permanent location. Test the mic at the  
farthest points from the sensor to confirm  
signal is clear throughout the classroom.  
(Dark surfaces reflect less infrared light and  
may hinder signal transmission.)  
Screw the plastic mounting strip  
on to a place high on the wall or in  
the middle of the solid ceiling.  
a. Suspended Ceiling Mount  
Firmly snap the C-clip on the back  
of the IR sensor onto the plastic  
mounting strip with the sensor plug  
hanging down (if a wall mount) or  
toward the receiver location (if  
ceiling mount).  
Uncoil the sensor wire. Insert sensor  
plug into the female end of the  
sensor wire. Loosely secure wire  
overhead and route it back to  
the LES 780iR.  
• Lift the ceiling tile nearest the grid rail in  
your desired sensor location. Guide one  
side of the C-clip over one edge of the  
grid rail. Providing firm support to the  
back of the grid rail with one hand (to  
prevent bending), firmly and carefully  
snap the second side of the C-clip over  
the edge of the rail.  
Connect sensor wire to any of the  
six sensor inputs on the back of  
the LES 780iR.  
Complete Step 7 (testing) to confirm  
optimum sensor location and  
permanently secure wire from the  
sensor back to the LES 780iR.  
Uncoil sensor wire. Insert sensor wire  
jack into sensor plug. Loosely secure  
wire overhead and route it back to  
the receiver.  
[ 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.  
• Plug into any of the six sensor inputs on  
the back of the LES 780iR.  
Complete Step 7 (Testing) to confirm  
optimum sensor location, and perman-  
tently secure sensor wire from the sensor  
back to the receiver.  
[4]  
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6. LightMic Microphone/  
Transmitter  
[ 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.  
For testing purposes, basic instructions  
for wearing and operating the LightMic  
are provided below. For more detailed  
instructions, refer to page 11.  
Clip the LightMic to the lavaliere.  
With volume and EQ levels set, walk  
around the room, paying special  
attention to the areas farthest from  
the IR sensor. Your voice should  
remain clear and intelligible.  
Place the LightMic and lavaliere cord  
around your neck and adjust cord  
length so the top of the LightMic sits  
just below your collar bone.  
Slide the ON/OFF switch on the  
LightMic to ON. e red power  
indicator will light.  
Consult the troubleshooting guide  
for further assistance.  
Slide the channel select switch to “A.”  
7. Testing  
Test the system to ensure everything is  
correctly connected and working proper-  
ly before your first full day of use. A  
second person is helpful to listen and  
ensure your voice is clear but not loud.  
With the LightMic positioned  
properly around the neck, speak  
normally and turn the A VOLUME  
clockwise until an optimum voice  
level is achieved. You may not be able  
to hear your own voice when this is  
properly set. However, your  
students will.  
[5]  
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Front Panel Controls  
3
5
4
2
1
1. POWER Switch/POWER Indicator:  
is switch is used to turn the LES 780iR  
ON (switch up), or OFF (switch down).  
When the POWER switch is in the ON  
position, the red POWER light  
will glow.  
4. A VOLUME: Controls the volume  
level of the microphone/transmitter  
that is switched to Channel A.  
Rotating the knob clockwise  
increases output level.  
5. B VOLUME: Controls the volume  
2. IR 1/IR 2: e IR indicators (IR 1/IR 2)  
will glow red when the corresponding  
microphone is turned on. is light  
confirms the LES 780iR is receiving the  
infrared signal.  
level of the microphone/transmitter that  
is switched to Channel B. Rotating the  
knob clockwise increases output level.  
3. AF 1/AF 2: e AF indicators (AF 1/AF 2)  
flash green when audio (voice) from the  
microphone is dectected.  
7
6
6. VOLUME (TV/VCR, CD/TAPE,  
COMPUTER, AUX): ese knobs  
control the volume of various audio  
sources that are connected to their  
corresponding input jacks on the  
back panel.  
7. SPEAKERS (1-6/OFF): ese ON/OFF  
switches turn the corresponding  
speaker (connected to the same  
numbered jack on the back of the unit)  
on or off. is is used for “zoning”  
multiple speakers within the classroom.  
[6]  
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Rear Panel Controls  
1
7. FILTERS: ese speaker filters are cov-  
ered with a speaker indicator label and  
are factory preset for optimum perfor-  
mance. If you have any questions about  
these filters or their settings please  
call LightSPEED.  
2
1. SPEAKERS (1-6) Volume Controls:  
ese knobs control the output volume  
of each corresponding speaker. e  
volume level is preset in the middle  
position at the factory. LightSPEED  
recommends leaving the volumes at  
this level for uniform sound throughout  
the classroom.  
8
9
8. AUDIO INPUTS (TV/VCR,  
CD/TAPE, COMPUTER, AUX):  
ese RCA input jacks receive audio  
input from external audio sources  
(TV/VCR, CD/tape, computer, etc).  
2. SPEAKER OUTPUT (1-6): ese 1/4”  
jacks are used to connect speaker cable  
from the loudspeakers to the LES 780iR.  
9. EQUALIZATION: e three frequency  
equalization adjustments are factory set  
for normal classroom environment.  
5
4
7
LOW: Controls low-frequency.  
MID: Controls mid-frequency.  
HIGH: Controls high-frequency.  
3
6
3. DC POWER: e LES 780iR uses  
an AC to DC power converter to supply  
power to the amplifier.  
11  
10  
4. FM OUT & AUX OUT: ese output  
jacks send the processed signal to  
external equipment—for example, a tape  
recorder or an assistive listening device  
like LightSPEED’s LES 370 Personal  
FM System.  
10. SENSOR INPUTS: e cable from  
the IR sensor connects to any of these  
six inputs. Up to six IR sensors can be  
connected to the LES 780iR for use in  
large or odd shape classrooms.  
5. ADJ: ese knobs control the output  
level of the audio source being sent out  
of the unit via the FM OUT & AUX  
OUT jacks.  
11. SENSOR SHORT: If there is a short in  
one of the sensor cables, this LED glows  
as a warning signal.  
6. MIC CHARGE: ese jacks are  
used to connect the charging cable to the  
LightMic or a handheld microphone  
for daily battery charging.  
[7]  
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System Operation:  
Powering the LES 780iR  
Check that:  
a.  
a
Both front panel microphone volume controls  
(A VOLUME and B VOLUME) are turned all the  
way down (fully counter-clockwise).  
b.  
Individual speaker switches are in the  
on/up position.  
b
c
c
e LES 780iR is connected to a power source. Use the  
enclosed AC/DC power adaptor to plug into a standard  
electrical outlet and connect the other end to the DC  
POWER jack on the back panel.  
d. Individual SPEAKERS volume knobs on  
d
back panel are set at a 12 o’clock position.  
d. e power switch located on the left side of the  
e
front panel of the LES780iR is in the up position  
(ON). e red POWER light on the POWER switch  
will light when the LES 780iR is on.  
[8]  
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LT-70 LightMic Microphone/Transmitter:  
Controls and Connections  
Microphone  
External  
Microphone  
Connector  
(MIC)  
Clip  
ON/OFF  
4
1
Switch  
3
Power/  
Channel  
Charge  
Select  
2
5
LED  
Switch  
Charging  
Indicator  
(CH A/B)  
Connector  
(CHARGER)  
1. ON/OFF Switch: is switch,  
located on the side of the LightMic,  
turns the unit on or off. e red  
triangle-shaped LED on the front  
of the LightMic will light when  
power is on.  
4. External Microphone Connector (MIC):  
Use the 3.5 mm MIC jack for the optional  
TK-250 headset microphone.  
5. Charger Connector (CHARGER): Use  
the jack labeled CHARGER to connect the  
charging cable from the LES 780iR to the  
LightMic for daily battery recharging.  
2. Channel Select Switch (CH A/B):  
is switch allows for selection  
between Channel A or B. If you  
are using a single microphone/  
transmitter for your system, we  
recommend using Channel A.  
3. Power/Charge LED Indicator:  
is triangle-shaped LED is two-  
color. It glows red when the LightMic  
is powered on, green when charging  
and goes out when fully charged.  
[9]  
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Charging the LightMic  
e rechargeable NiMH  
batteries must be fully charged  
before regular classroom  
operations.  
1. Ensure the LightMic is turned OFF.  
e LES 780iR must be connected  
to AC power in order to charge the  
LightMic.  
However, do not leave the LightMic plugged  
into the charger for more than 10 days, as it  
will significantly shorten battery life.  
6. Once the batteries are charged,  
remove the charging cable from  
the LightMic.  
2. e LightMic’s rechargeable batteries  
are factory installed. Plug one end of  
the charging cable firmly into the jack  
labeled CHARGER on the side of the  
LightMic. Connect the other end of  
the charging cable to one of the MIC  
CHARGE jacks on the back of the  
LES 780iR.  
7. NiMH batteries will maintain their  
charge for a full day of normal  
classroom use.  
8. With proper care, NiMH batteries  
will provide service for at least one  
year. If battery or charging problems  
occur, contact LightSPEED Service at  
800.732.8999.  
3. e triangle-shaped light on the  
front of the LightMic transmitter  
glows green when the cable is  
connected and charging correctly.  
e light goes out when fully charged.  
[ caution! ]  
4. e batteries will fully charge in  
8 to 12 hours.  
Do not attempt to charge alkaline  
batteries̶they can overheat and  
expand, creating a significant hazard  
5. It is best to leave the LightMic  
charging until used, since the  
batteries slowly lose their charge  
when not in use.  
and damaging the LightMic.  
(is is not covered by the warranty.)  
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Operating the LightMic  
a. e LightMic has a built-in microphone.  
Once the transmitter is switched on, the  
microphone is activated.  
d. Speak at a normal level and slowly  
turn the volume knob clockwise to  
increase the loudness of the speaker(s)  
until the sound level is adequate for  
the room.  
b. e LightMic may be used as a hand-  
held mic or a hands-free pendent style  
microphone by clipping the LightMic  
on the supplied lavaliere cord.  
[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.  
Place the lavaliere cord around your neck,  
and adjust the length so the top of the  
LightMic rests on the collar bone.  
Operating two microphone/  
transmitters simultaneously  
c. On the side of the LightMic is the Chan-  
nel select switch. Slide the switch to  
the “A” position. (If a second LightMic  
is used for simultaneous operation, set  
one LightMic to Channel A and the  
second LightMic to Channel B.)  
e LES 780iR has two independent  
receivers—Channel A and B. is makes it  
possible to operate two microphones simul-  
taneously. Follow the instructions below  
when using a second microphone:  
d. Slide the ON/OFF switch on the side of  
the LightMic to ON. e triangle-  
shaped light on the front glows red,  
indicating the microphone is charged  
and ready for use.  
a. Set each microphone/transmitter to  
separate channels. For example if  
you are using two LightMics, set one  
to Channel A and the other to  
Channel B. If you are using one  
LightMic and one HM-70 handheld  
microphone, set the LightMic to  
Channel A and the HM-70 to  
Channel B.  
e. When the LightMic transmitter  
ON/OFF switch is slid to OFF, the  
microphone power is turned off.  
Adjusting Volume  
Volume is set by adjusting the volume control  
on the LES 780iR.  
When the LES 780iR is receiving a signal  
from the microphone/transmitters:  
a. Ensure the LES 780iR is switched ON.  
• IR 1 indicator to the left of the A  
volume knob will glow red on the  
LES 780iR when Channel A on the  
LightMic is selected  
b. Ensure the LightMic is switched ON and  
the triangle-shaped LED on the front of  
the LightMic is glowing red. e IR 1  
LED next to the A VOLUME knob on  
the LES 780iR will also glow, indicating  
that the LES 780iR is receiving the  
• e IR 2 indicator light to the left of the  
B VOLUME knob will glow red  
when Channel B is selected.  
LightMic signal and is ready for use.  
• When simultaneously operating two  
microphone/transmitters, both  
indicator lights will glow.  
c. Adjust the volume of the receiver by  
turning A VOLUME clockwise.  
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Optional HM-70 Handheld  
Microphone/Transmitter:  
Overview  
HM-70 Controls  
1. Power Switch: is 3-position  
switch allows you to turn the micro-  
phone on (up position), mute the  
microphone (middle position), and  
turn off the microphone (down posi-  
tion). e red LED above the switch  
lights when the switch is in the  
e HM-70 handheld microphone/  
transmitter is an optional microphone  
that can be ordered from LightSPEED.  
It can be used alone or in tandem with the  
LT-70 LightMic.  
“mute” or power “on” positions.  
2. Channel Select Switch: is switch  
allows you to choose between Channel  
A or Channel B. is switch is set to  
Channel B at the factory.  
Power/Charge LED  
3
Indicator  
3. Power/Charge LED Indicator: is  
two-color LED indicator is located  
directly above the power switch. It  
glows red when the HM-70 is powered  
on and glows green when charging.  
Power Switch  
1
slide to open  
4. Charger: Use this jack to connect the  
charging cable from the 780iR to the  
HM-70 for daily battery recharging.  
4
Battery  
Charging Jack  
Compartment  
[ caution! ]  
Channel Select Switch  
2
Do not attempt to charge alkaline  
batteries̶they can overheat and  
expand, creating a significant hazard  
and damaging the LightMic.  
(is is not covered by the warranty.)  
Gain Adjust  
top view of battery compartment  
[12]  
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HM-70 Operating Instructions  
Charging  
Operation  
e Channel A/B switch is located inside  
the battery compartment. e switch is set to  
Channel B at the factory.  
Rechargeable batteries are pre-installed.  
a. Turn off the HM-70 by sliding the  
power switch all the way down.  
a. Slide the power switch on the side of  
the HM-70 all the way up. e power  
indicator LED will glow red and stay on.  
(ere is a center MUTE position if you  
wish to leave power on but temporarily  
cease transmission of your voice.)  
b. Connect one end of the charging cable  
to one of the MIC CHARGE jacks on  
the back panel of the LES 780iR.  
Connect the other end of the charging  
cable to the charging jack on the side of  
the HM-70. e power indicator LED  
will glow green when the charging  
cable is connected and charging  
correctly.  
b. Do not adjust the audio gain adjuster  
that is located in the battery compart-  
ment. It has been preset by factory  
technicians and is not intended as a  
volume control.  
c. e batteries fully charge in 8 to 12  
hours. Once the batteries are charged,  
remove the charger cable from the  
HM-70.  
Holding and Positioning  
a. When holding the HM-70, grip the  
barrel in the center, silver section  
NiMH batteries maintain their charge for  
a full day of normal classroom use. Always  
turn the HM-70 off when not in use.  
below the power switch. Do NOT  
grip the HM-70 around the bottom,  
covering the black infrared sensors  
encircling the base. is interrupts  
signal transmission from the microphone  
to the receiver. Speak directly into the  
top of the microphone at a normal level,  
holding the head about 2 inches from  
your mouth, no lower than chin height.  
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Input from External  
Audio Equipment  
While LightSPEED recommends leaving the  
speaker volume set in the middle position  
to maintain a uniform sound, there may be  
times when separate volume adjustments are  
necessary.  
Below are instructions on how to connect  
an external audio device like a TV/VCR,  
CD/DVD, cassette player, or projector.  
Turning Speakers On and Off  
1. Connect an RCA cable from the  
audio source to one of the four (4)  
AUDIO INPUT jacks on the back of  
the LES 780iR using an RCA-type male  
connector. If the audio source produces  
a stereo signal, a stereo to mono adapter  
is required (Part # AC-STM-ADPT).  
1. Ensure that the LES 780iR is turned off  
and that A and B VOLUME  
are turned down.  
2. Turn the corresponding SPEAKERS  
(1-6)/OFF switch(es) on the front  
panel to the on (up) position.  
2. With the LES 780iR on, adjust the cor-  
responding volume knob on the front  
to a desired level.  
3. Turn the LES 780iR on and slowly turn  
up the level of A VOLUME. Walk  
around the classroom speaking into the  
mic at a normal level and ensure that the  
desired volume is coming from each  
speaker. Do the same with B VOLUME  
if using a second LightMic.  
Output to Personal  
FM Transmitter  
1. Using a cable with a 3.5 mm connector  
at one end, connect the FM OUT or  
AUX OUT to the input jack of an FM  
transmitter, recorder, or other device.  
It is important to determine the size and  
type of audio input jack on the device as  
many manufacturers’ products differ.  
e LightSPEED LES-370 requires the  
CA-MMC3535 cable.  
Controlling the Volume of  
the Individual Speakers  
An area of the classroom may contain a  
noise emitter such as an HVAC system. In  
this case, it may be necessary to turn up the  
volume of the affected speaker to overcome  
the noise in that area.  
2. With the LES 780iR turned on, adjust  
the FM OUT or AUX OUT volume  
on the back of the LES 780iR to a  
desired level.  
When his situation arises, the LES 780iR  
allows the user to fine tune the output level:  
1. Locate the speaker volume control knobs  
on back panel (SPEAKER 1-6) above  
the speaker outputs.  
Speaker Control  
e LES 780iR has six individual speaker  
outputs, each with its own on/off switch  
and volume control. By “zoning” or sepa-  
rating the classroom into different  
areas where audio may or may not be de-  
sired, the teacher has greater flexibility  
controlling the dispersion of sound  
2. If possible, have a second person stand  
by the speaker(s) needing adjustment.  
3. Speak into the mic at a normal level  
and adjust the corresponding speaker  
volume control(s) (SPEAKER 1-6) to a  
desired level.  
throughout the room. Zoning is especially  
useful in large or odd-shaped classrooms.  
Turning speaker volume too high can result in  
feedback when walking under speaker.  
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Tips on Using Classroom  
Amplification  
Five-Year Limited Warranty  
to Original Purchaser  
ese helpful suggestions are provided  
to maximize the successful use of  
your new LES 780iR Infrared Classroom  
Amplification System.  
e LightSPEED LES 780iR Infrared  
Classroom Amplification System is war-  
ranteed against malfunction due to defects  
in materials and workmanship for a period  
of five years beginning at the date of the  
purchase. Batteries and the optional TK-  
250 Headset Microphone are guaranteed  
for one year. Products will be repaired or  
replaced at LightSPEED’s option during  
the warranty period.  
• Speak in a natural voice. A normal  
conversational speech level will provide  
an adequate signal. It is not necessary to  
increase the intensity of your voice—the  
amplification system provides adequate  
amplification (approximately 5 - 10 dB)  
above ambient room noises.  
Warranty does not extend to finish, ap-  
pearance, or malfunctions due to abuse or  
misuse. Repairs performed by any other  
than LightSPEED will void this warranty.  
Our Service Department (800.732.8999,  
7 a.m. – 5 p.m., PST) will handle  
• Avoid wearing jewelry that may rub or  
bump against the microphone.  
Turn the LightMic off during private  
conversations with a student, parent, or  
other classroom visitor. You can also  
cover the LED lens on top of the  
LightMic to block the signal.  
all your repair/replacement needs.  
If you review these instructions and still  
have questions, write down the serial  
number and model number of your system  
and call LightSPEED Technical Services at  
800.732.8999, 7 a.m. - 5 p.m. PST.  
• Recharge batteries each night. When  
recharged nightly, operating time  
(actual usage) for the transmitters will  
last through a typical school day. Your  
rechargeable batteries will last for a  
normal school year when cared  
for properly.  
[ caution! ]  
Do not attempt to charge alkaline  
batteries̶they will overheat and expand,  
creating a significant hazard and damaging  
the transmitter. (This type of damge is not  
covered under warranty.)  
[15]  
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Overall System Specifications:  
Carrier Frequencies (IR)  
Frequency Stability  
Maximum Deviation  
Dynamic Range  
2.06/2.54 MHz  
+/‒ 3%  
+/‒ 50 kHz  
> 80 dB  
Signal-to-Noise Ratio  
Frequency Response  
> 90 dB  
40 Hz - 20 kHz (‒ 3 dB)  
Receiver Specifications:  
Receiver Type  
Superheterodyne  
6 µV for 60 dB S/N ( > 25 dBuV)  
> 40 dB  
Receiver Sensitivity  
Image and Spurious Rejection  
Reception Selectivity  
Squelching  
40 kHz  
Threshold 3.2 µV  
Amplifier Specifications:  
Power Output (System Total)  
Total Harmonic Distortion  
Speaker Load Impedance  
Power Supply (UL Listed)  
Dimensions  
12 W per channel (72 W)  
< 1% @ 20 W  
4 Ohms  
24 V/2.5 A  
18 x 9 x 3 (H x W x D inches)  
7 lbs.  
Weight  
Inputs:  
TV/VCR  
RCA ‒ Line Level  
RCA ‒ Line Level  
RCA ‒ Line Level  
RCA ‒ Line Level  
“F” Connector  
CD/Tape  
Computer  
Auxiliary  
IR Sensors (6)  
Outputs:  
Auxiliary Outputs (2)  
3.5 mm  
1/4”  
Speaker Outputs (6)  
Transmitter Specifications:  
Audio Distortion  
Spurious Emissions  
Built-in Microphone  
Battery Power (1-year warranty)  
Dimensions  
< 1%  
< 30 dB  
Uni-directional Electret  
2 AA NiMH Rechargeable  
1.4 x 1 x 4.6 (W x D x H inches)  
3.04 oz (w/batteries)  
Weight  
External Sensor:  
Power  
By Receiver Unit  
360 º, Ceiling-mount  
40 ft., Plenum-rated Co-ax  
Ceiling clip/Wall bracket  
32  
Reception Coverage  
Cable  
Mounting  
Diodes  
[16]  
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Troubleshooting Guide  
No Sound From Speaker:  
Please go through this checklist before calling  
LightSPEED Service Department.  
Confirm the LightMic and the  
LES 780iR are turned on and have  
matching channels. Check both  
A VOLUME and B VOLUME  
to ensure they are set correctly.  
Battery Check:  
Confirm batteries are charged each  
night. With proper charging,  
batteries will last about one  
school year.  
Confirm amplifier power supply is  
the correct type—if in doubt, call  
LightSPEED. In addition, confirm  
that the power supply is connected  
securely in the wall outlet and into  
the DC POWER connector  
Transmitters are charged via a  
jumper cable from the back of the  
LES 780iR. Make sure plugs are  
secured and in the proper jacks.  
on the back of the 780iR.  
Turn the 780iR on. Confirm that  
the POWER light located on the  
front panel switch is on.  
Confirm the green charging light  
located on the front of the LightMic  
is on while charging.  
Turn the LightMic on and confirm  
that the corresponding red IR light,  
located on the front panel of the  
LES 780iR, lights. When speaking  
into the LightMic, the green AF  
light will flash/flutter with your  
voice volume.  
Ensure the LightMic is turned off  
while charging.  
Hearing Static or Buzzing:  
If using two LightMics, check that  
they are not set to the same  
channel. If so, select a different  
channel for one of the LightMics.  
Confirm that the batteries in the  
transmitter are fully charged. When  
they are, the red indicator will  
glow steadily.  
Keep the LES 780iR at least 6 feet  
away from computers.  
Low Volume:  
Confirm that the speaker wires are  
in the correct jacks on the back of  
the LES 780iR and confirm that the  
speaker switch for that speaker  
output is in the ON position. Also,  
confirm that the volume level for  
each connected speaker is set in the  
middle position (12 o’clock).  
Check volume level on the LES  
780iR and adjust as necessary.  
Check volume level on each of the  
speakers (on back panel) and adjust  
as necessary.  
Sound Fades In and Out  
(Drop Out):  
Test LightMic with fully charged  
batteries. LED light on front of mic  
will glow bright red.  
[17]  
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Individual Components and Optional Accessories  
LES-780C:  
LES-LT70:  
Infrared Receiver/Amplifier/Mixer with built-in  
charger  
“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:  
IR-SR70:  
Power Supply/Battery Charger for 780iR  
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:  
CA-MMC2535:  
SPEAKERS:  
Audio Patch Cable (3.5 mm mono to 3.5 mm mono)  
Audio Patch Cable (2.5 mm mono to 3.5 mm mono)  
Contact LightSPEED at 800.732.8999 for  
loudspeaker information  
[18]  
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User Notes  
Record your system serial numbers and purchase information. is is helpful when  
ordering additional components, accessories, and/or warranty service.  
standard  
serial number  
components  
LES 780iR  
LT-70 LightMic  
SR-70 IR Sensor  
Speakers  
Power Supply  
n/a  
RCA Cables  
optional  
serial number  
component  
HM-70 Handheld  
Microphone  
TK-250 Headset  
Microphone  
Wall-Mounting Shelf  
[19]  
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L I G H T S P E E D T E C H N O L O G I E S , I N C .  
1 1 5 0 9 S W H E R M A N R D  
T U A L A T I N , O R 9 7 0 6 2  
8 0 0 . 7 3 2 . 8 9 9 9  
W W W . L I G H T S P E E D - T E K . C O M  
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