on your purchase of the Sennheiser Digital Wireless System. This is a stateof-the-art 900 MHz (UHF) digital audio transmission system and is capable
of outstanding audio and RF performance in combination with high-grade
amplification, mixing and recording systems.
Sennheiser proudly presents this advanced new standard in audio
transmission to musical and audio professionals as proof of Sennheiser’s
non-compromising pursuit of the ultimate in RF and audio performance.
Your digital wireless system is designed for superb audio quality and wireless
performance as well as continued reliability. To familiarize you with your
new digital wireless system, we suggest that you read through this entire
operation manual.
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2Features
•16-bit A/D–D/A conversion for CD quality sound.
•No compander ICs – for the transient response and “feel” of
a wired connection.
•Frequency Clear™ UHF Digital: System transmits a
proprietary digital signal on a 900 MHz UHF carrier for
freedom from multi-pathing and interference, including
HDTV.
•Quadiversity™ receiver – one UHF receiver, four internal
antennas, all microprocessor-controlled for freedom from
dropouts.
•Scanner-proof security: Proprietary digital transmission is
scanner-proof for eavesdrop-free peace of mind.
•Operating range of 80 – 130 feet under adverse conditions,
280 feet line of sight.
•Nine-segment LED display shows important performance
parameters including audio level and transmitter battery life.
This device complies with part 15 of the FCC rules. Operation is subject to
the following two conditions:
1This device may not cause harmful interference, and
2this device must accept any interference that may cause
undesired operation.
5
3Important notes
Never open electronic devices! This must only be done by authorized
personnel, especially for units connected to AC outlets. If devices are opened
by customers in breach of this instruction, the warranty becomes null and void.
Always disconnect the devices from the mains by removing the plug when
you wish to change connections or move the devices to a different place.
Never connect conventional RF antennas to the BNC sockets as these can
damage the receiver!
Keep the devices away from central heating radiators and electric heaters.
Never expose them to direct sunlight.
Use the devices in dry rooms only.
Use a damp cloth for cleaning the devices. Do not use any cleansing agents
or solvents.
4System variants
Vocal Set 1091 DIGITAL
This system is ideal for vocal applications.
Set 1091 DIGITAL consists of: EM 1090 DIGITAL receiver, SKM 1091
DIGITAL handheld transmitter with supercardioid dynamic microphone
module, microphone clamp, plug-in mains unit, battery and operating manual.
Instrumental Set 1092 DIGITAL
This system is for connecting musical instruments (e.g. guitar) which have a
1/4” jack socket.
Set 1092 DIGITAL consists of: EM 1090 DIGITAL receiver, SK 1093
DIGITAL belt pack transmitter, instrument (guitar) cable, plug-in mains unit,
battery and operating manual.
Bodypack Set 1093 DIGITAL
This system is ideal for presentation and PA applications in acoustically
difficult rooms. The unobtrusive clip-on electret microphone (omnidirectional)
can be directed towards the speaker’s mouth.
Set 1093 DIGITAL consists of: EM 1090 DIGITAL receiver, SK 1093
DIGITAL belt pack transmitter, miniature clip-on electret microphone
(omnidirectional), plug-in mains unit, battery and operating manual.
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5Preparing the devices for use
5.1EM 1090 DIGITAL receiver
POWER button
“Power on/off” control LED
“RF” control LED
“Data” control LED
6-segment level display for
- incoming AF signal
- transmitter battery life
Channel selector switch
BNC socket 1 for connection of additional A 1090 DIGITAL antenna
AF output, unbalanced, 1/4” jack (line level)
AF output, balanced, XLR-3M
AF output level control (for outputs and )
Cable grip for power supply DC cable
DC socket for connection of mains unit
BNC socket 2 for connection of additional A 1090 DIGITAL antenna
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Connecting the mains unit
씰Insert the DC connector on the power supply output cable into
socket (refer to page 7) at the rear of the receiver.
씰Pass the cable through the cable grip .
Connecting the amplifier/mixing console
씰Connect the amplifier/mixing console either
– to the XLR-3M socket or
– to the 1/4” jack socket .
Adjusting the AF output level
씰Use the AF output level control to adjust the AF signal level that
appears at outputs and .
Switching the receiver on/off – Selecting a channel
씰Press the POWER button to switch the receiver on.
씰Use the channel selector switch to select a channel.
Connecting additional A 1090 DIGITAL antennas
Additional digital antennas can be connected to the BNC sockets and
if the range of the receiver’s internal antennas is not sufficient. This may
happen if receivers are mounted into a rack or are installed between metal
constructions on a stage.
For connecting the antennas, use 50 Ω coaxial cable with BNC connectors.
Ready made up antenna cables from Sennheiser are available as accessories
(see chapter 11).
Depending on the location you can connect one or two digital antennas.
Attention:
Never connect conventional RF antennas to the BNC sockets as these
can damage the receiver!
8
Indicators on the EM 1090 DIGITAL receiver
The 3-segment LED display on the left of the front panel provides information
on the operating state of the EM 1090 DIGITAL receiver:
Red LED “ON”:
The LED lights up to show that the receiver is connected to the mains
and has been switched on with the POWER button .
Red LED “RF”:
An RF signal from the suitable transmitter is being received by the receiver.
In contrast to analog transmission, digital test signals are also received so
that the transmitter can be identified.
Red LED “DATA”:
After the receiver has checked the suitable transmitter and accepted the digital transmission, the LED indicates that a data stream is being received.
“AF LEVEL” indication
The 6-segment LED display on the right of the front panel indicates the AF
level, i.e. the incoming audio signal. The segments of the LED display start
lighting up from the left.
Adjust the sensitivity of the SK 1093 DIGITAL belt pack transmitter such
that the last (right-hand) LED segment does not light up. The sensitivity of
the SKM 1091 DIGITAL handheld transmitter is automatically adjusted.
“BATTERY” indication
As long as the transmitter doesn’t transmit any audio signal (e.g. during
pauses in speaking), the 6-segment LED display indicates the remaining
transmitter battery capacity. The segments of the LED display start lighting
up from the right.
If the battery is going flat, the last (left-hand) LED segment will light up. You
should replace the battery within the next 20 minutes (value depending on
battery type).
씰Slide the cover of the battery compartment in the direction of
the embossed arrow until it clicks audibly.
씰Open the cover.
씰Insert the 9 V PP3 battery (IEC 6 LR 61). Please observe
correct polarity when inserting the battery.
씰Close the battery compartment.
씰To remove the battery, push the small red lever in the battery
compartment towards the bottom side of the transmitter.
Note:
We recommend powering the transmitter by a standard PP3
alkaline battery. If powered by a rechargeable 9 V battery, the
operating time will be drastically reduced.
Connecting the antenna
씰Screw the antenna onto the antenna socket (M3 connection).
Connecting the microphone/line cable
Electret powering (“plug-in” power) is available at the AF input for powering
the microphone.
씰Connect the 1/8” jack plug from the microphone/line cable to the AF
input .
씰Lock the jack plug by screwing down the locking ring.
Switching the transmitter on/off
씰Slide back the cover plate.
씰Set the ON/OFF switch to ON. The green LED lights up.
Battery life indication
The red LED provides information on the battery life. LED lit up:
The battery is going flat! You should replace the battery within the next 20
minutes (value depending on battery type).
Attachment of the transmitter to clothing
씰The belt pack transmitter is best attached to e.g. the belt with the
supplied clip.
씰The clip is detachable so that you can also attach the transmitter with
the antenna pointing downwards. To do so, withdraw the clip from
its fixing points and attach it the other way round.
11
5.3SKM 1091 DIGITAL handheld transmitter
Battery compartment
HIGH/LOW dynamic window switch
ON/OFF switch
Power control LED
Removeable sound inlet basket
12
Inserting the battery
Open the battery compartment and insert the battery, taking care to observe
the correct polarity.
IEC 6 LR 61
씰Please use type 9 V PP3 (IEC 6 LR 61) alkaline batteries. They ensure
an operating time of approx. 4 hours (value depending on battery
type).
씰N.B.: Using NiCd rechargeable batteries is unadvisable as this would
reduce operating time to under two hours (technical data are not
affected).
Switching on the handheld transmitter
Switch on the SKM 1091 DIGITAL handheld transmitter by setting the
ON/OFF switch to ON.
After a short time, the red LED below the ON/OFF switch will light up,
indicating that the handheld transmitter is now ready for operation.
Selecting a transmission channel
Use the rotary switch at the side of the handheld transmitter to choose one
of the 4 possible transmission channels. The corresponding transmission
frequencies are listed on a sticker in the battery compartment.
Transmitter and receiver must operate on the same channel!
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6Troubleshooting
씰The transmission fails completely
Short-period switching off and back on again the EM 1090 DIGITAL
receiver may lead to an interrupt in transmission.
After having switched off the receiver hang on for a couple of seconds
before switching on again as with any processor-controlled device.
씰The transmission range is not sufficient
Use remote antennas. You can connect two additional A 1090 DIGITAL
antennas to the EM 1090 DIGITAL receiver. The remote antennas
can be installed at a distance of up to 30 meters from the receiver.
씰You can hear crackling noise and – occasionally – another
transmitter is being received
A second DIGITAL transmitter is operating on the same transmission
frequency. In contrast to analog audio transmission, both transmitters
are received simultaneously. If the field strengths of both transmitters
are almost similar, the receiver switches to and fro between the two
transmitters – crackling noise occurs – and possibly, the “DATA”- LED
goes off.
Choose a different transmission channel.
씰You can hear “crosstalk”
Observe a minimum distance of 3 meters between transmitter and
receiver.
씰Crackling noise and dropouts occur during the operation
with a clip-on microphone
The jack plug from the microphone cable is not screwed tightly to the
SK 1093 DIGITAL. Lock the jack plug by screwing down the locking
ring.
씰Before deciding on a transmission channel, test – with the receiver
only – whether the chosen channel is free. Switch on the receiver and
listen to the channel. When you are sure that no one else is occupying
this channel, you can set the radiomicrophone to the same frequency.
7Installation in a 19" rack
Slide the supplied rack mount adapters and two receivers together as
illustrated. The receivers can now be bolted into the rack.
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Instead of a second EM 1090 DIGITAL receiver you can also use a
GA 1031 CC blank module or a GA 1031 AM antenna mount.
8Care and maintenance
SKM 1091 DIGITAL handheld transmitter
The SKM 1091 DIGITAL’s sound inlet basket should be cleaned from time to
time.
씰Unscrew the inlet basket (turn anti-clockwise) and remove it.
씰Rinse foam protection and sound inlet basket with warm water.
씰Dry both foam protection and sound inlet basket with a hairdryer.
Note:
Do not use any cleansing agents or solvents. Do not touch the microphone contacts.
Take off the sound inlet basket carefully in a straight line taking care
of the microphone capsule!
씰Screw the sound inlet basket back tight on the SKM 1091 DIGITAL
transmitter.
9Connector assignment
1/8” stereo jack plug1/4” jack plug, unbalanced,
(lockable), SK 1093EM 1090
XLR-3 connector, balanced,DC connector/Power supply
EM 1090
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10Technical data
Overall system
Transmission formatSennheiser proprietary digital
audio transmission
Frequency response20 Hz to 15 kHz
Audio dynamic range> 120 dB
Distortion< 0.2 % THD
RF carrier frequency905 MHz to 925 MHz
Number of selectable frequencies4