Sennheiser SZI 30 Operating and maintenance instructions

SI 30/SZI 30
Features
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Compact radiator and modulator/radiator for the carrier
frequencies 2.3 MHz and 2.8 MHz
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Easy installation and precise alignment
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Delivery includes:
SI 30: 1 x SI 30 modulator/radiator, 1 x AF connection cable, 3.5 mm stereo jack
plug to Texas connector, length 2 m, 1 x 3.5 mm/1/4“ stereo jack adaptor
SZI 30: 1 x SZI 30 radiator
The NT 20-1 plug-in mains unit is not included in the delivery. Please order
it separately in the version you require (European, UK or USA versions available).
General Description
The SI 30 is a wideband modulator with an integral radiator. It can be switched
between operation on channel 1 (2.3 MHz), channel 2 (2.8 MHz) and stereo operation.
Due to its compact size and relatively low radiating power, the SI 30 modulator/
radiator and the SZI 30 radiator are an ideal choice for smaller or medium-sized
rooms, for covering recesses or for applications which require transmission of audio
information to well defined zones, e.g. in museums.
Technical Data SI 30
Modulation ....................................................... wideband FM
Nominal deviation .................................................. ± 50 kHz
Carrier frequencies ..................................2.3 MHz, 2.8 MHz
AF input................................................... 3-pin Texas socket
AF input voltage for
nominal deviation..............................................45 mV – 4 V
(automatic modulation control)
AF frequency response...............................30 – 18,000 Hz
THD (1 kHz, nom. dev.) .................................................≤1 %
AF signal-to-noise ratio.................................. ≥60 dB(A)rms
RF output..................................................3.5 mm mono jack
Output impedance............................................approx. 50 Ω
IR diodes................................................................................11
Max. coverage area .................. approx. 80 m2, single-chn.
Radiating power ............................................. approx. 0.5 W
Operating voltage............................ 24 – 27 V DC via 2-pin
Texas socket
Current consumption ................................. approx. 180 mA
Dimensions ................................approx. 118 x 25 x 90 mm
Weight .............................................................. approx. 140 g
Technical Data SZI 30
Nominal deviation .................................................. ± 50 kHz
Carrier frequencies ............................................ max. 6 MHz
AF frequency response................ depends on modulator
THD (1 kHz, nom. dev.) .................................................≤1 %
AF signal-to-noise ratio ................................ ≥60 dB(A)rms
RF input ....................................................3.5 mm mono jack
RF output......................................3.5 mm mono jack with a
50-Ωterm. impedance
Output impedance.........................approx. 20 kΩor 50 Ω*
IR diodes................................................................................11
Max. coverage area .................. approx. 80 m2, single-chn.
Radiating power ............................................. approx. 0.5 W
Operating voltage............................ 24 – 27 V DC via 2-pin
Texas socket
Current consumption ................................. approx. 150 mA
Dimensions ................................approx. 118 x 25 x 90 mm
Weight .............................................................. approx. 135 g
*see description on the following pages
IR Audio Transmission Technology | Modulators/Radiators

SI 30/SZI 30
Dimensions of the SI 30 / SZI 30
25 mm
118 mm
90 mm
0
10
20
30
40
50
60
70
80
121110987654321 Channels
m2
Coverage area of the SI 30 / SZI 30
Recommended Accessories
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Plug-in mains unit
NT 20-1 European version Cat. No. 003600
NT 20-1-120 USA version Cat. No. 003601
NT 20-1-UK UK version Cat. No. 003602
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Mains unit for up to four SI 30 / SZI 30
NT 20-4 European version Cat. No. 003603
NT 20-4-120 USA version Cat. No. 003604
NT 20-4-UK UK version Cat. No. 003605
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RF connection cable (2 x 3.5 mm jack)
KR 20-7 (7.5 m) Cat. No. 003535
KR 20-015 (0.1 m) Cat. No. 003536
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AF extension cable (2 x Texas)
KK 20-1 (1 m) Cat. No. 003557
KK 20-7 (7.5 m) Cat. No. 003558
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KK 20-015 4-way “octopus” cable (Texas) Cat. No. 003599
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IZK 20 mounting clamp Cat. No. 003560
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IZM 20 cluster mounting kit Cat. No. 003561
IR Audio Transmission Technology | Modulators/Radiators

SI 30/SZI 30
SI 30 front panel
SI 30 Modulator/Radiator
The SI 30 is a miniature combination modulator/radiator. It is slim and compact but
can cover areas of up to 80 m2in mono operation. The integrated modulator uses
stereo wideband modulation. When the audio signal at the SI 30 input exceeds a
certain threshold value, the modulator/radiator is switched on automatically. It
switches off again when there has not been an audio signal for about 2 minutes.
Transmission is indicated by a green LED on the left of the front panel.
The radiator of the SI 30 comprises 11 IR transmission diodes connected in series.
The AF input of the SI 30 is a 3-pin Texas socket located at the back of the unit, on
the left. It is an unbalanced stereo input, so you should not use long connection
cables. A 2 m connection cable with 3.5 mm stereo jack to a 3-pole Texas connector
is supplied as standard.
An automatic modulation control adapts to audio signals between 45 mV and 4 V.
This process is effected over a period of about one minute, so that short speaking
pauses do not entail a greater amplification. Problems may arise when you are work-
ing with microphones and very different signal levels. Longer breaks can lead to a
strong increase in amplification.
When connecting the SI 30 to headphone sockets of TV sets or similar sound sources,
you should adjust the level to a medium value. Too low a level results in more noise.
With the channel selector switch, you can choose between channel 1 or 2 trans-
mission or stereo operation. In mono operation, the integrated radiator and all
connected radiators can cover a greater area. For mono transmission, choose the
frequency suitable for the receiver, e.g. 2.3 MHz (channel 1) for the RI 150.
The RF output for connection of additional radiators is designed as a 3.5 mm mono
jack socket. You can connect both SZI 30 mini radiators or high-power radiators such
as the SZI 1029. For short distances, you can use connection cables from the Senn-
heiser accessory range. When working with greater cable lengths, you can make
your own cables using standard 50-ΩRG 58 co-axial cable.
The NT 20 plug-in mains unit is connected to a 2-pin socket at the back of the SI 30.
For supplying clusters, e.g. one SI 30 modulator/radiator and two SZI 30 radiators,
you can use the NT 20-4 plug-in mains unit and a KKY 20-015 4-way “octopus”
cable for connection. They have been designed for up to four SI 30 / SZI 30 units.
1 LED indicator for transmission mode
2 11 IR transmission diodes
21
SI 30 back panel
1 AF input (3-pin Texas socket)
2 Channel switch (stereo, channel 1, channel 2)
3 RF output (3.5 mm mono jack)
4 Power supply socket (2-pin Texas)
21 3 4
Connector assignment in stereo operation
Texas
connector 3.5 mm
stereo jack
ground
AF + right channel
AF + left channel
Connector assignment in single-channel operation
Texas
connector 3.5 mm
stereo jack
ground
not assigned
AF signal
IR Audio Transmission Technology | Modulators/Radiators

SI 30/SZI 30
SZI 30 Mini Radiator
The SZI 30 is a miniature-sized radiator which can be fed modulated signals from
an SI 30 or any other modulator. In narrow-band systems it can transmit frequencies
of up to 1.3 MHz (channel 31). It has no charging compartments, the LED on the
right of the front panel serves as a power indicator instead, showing that a supply
voltage is present.
At the back of the SZI 30 you have – besides the DC input connector – two RF
sockets. If no plug is connected to the output socket, a 50-Ωterminating impedance
is switched into the RF connection.
SI 30 / SZI 30 – Common Features
With their 11 IR transmission diodes, the SI 30 and SZI 30 can cover areas of up to
80 m2. In two-channel (stereo) operation, coverage is reduced to 40 m2. A signal-to-
noise ratio of 26 dB (the outer of the two characteristics in the polar diagram) gives
an intelligible but noisy signal. Only a signal-to-noise ratio of > 40 dB ensures com-
fortable listening without the annoying noise.
SI 30 modulators/radiators and SZI 30 radiators are especially suitable for the
following applications:
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As small wideband systems, e.g. for transmitting TV sound. Such a system can
consist entirely of SI 30 and SZI 30.
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As auxiliary radiators in combination with the SZI 1029, for covering room niches
and recesses.
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As “island solutions” – e.g. for exhibits in a museum. Such a system can econom-
ically be implemented using the SI 30. The individual areas within the museum
have to be optically decoupled, giving the visitor exactly the audio information
which is associated with the exhibit he or she is facing – without having to switch
channels.
With the IZK 20 mounting clamp and the IZM 20 cluster mounting kit, up to four SI 30/
SZI 30 can be mounted on top of one another. This makes it very easy to align them
correctly, at an angle to one another. The diagram on the left shows an installation in
which the radiators have been mounted in 60° steps. The result is an almost uniform
coverage over an angle of 200°.
SZI 30 back panel
1 RF socket J2 (3.5 mm mono jack)
2 RF socket J1 (3.5 mm mono jack)
3 Power supply socket (2-pin Texas)
1 2 3
33m
30m
27m
24m
21m
18m
15m
12m
9m
6m
3m
36m
39m
42m
45m
20˚
10˚
30˚
40˚
50˚
60˚
70˚
80˚
90˚
20˚
10˚
30˚
40˚
50˚
60˚
70˚
80˚
90˚
26dB
40dB
Polar pattern of the SI 30 / SZI 30
free field, extraneous light < 100 lx, single-channel operation
Four SZI 30, mounted at an angle of 60° to one
another. For comparison purposes, the coverage of
a single SZI 30 is shown at 30°.
33m
30m
27m
24m
21m
18m
15m
12m
9m
6m
3m
36m
39m
42m
45m
20˚
26dB
40dB
10˚
20˚
30˚
40˚
50˚
50˚
40˚
30˚
20˚
10˚
60°60°
60°
Radiator cluster with four IZK 20 clamps and IZM 20 cluster mounting kit
IR Audio Transmission Technology | Modulators/Radiators

SI 30/SZI 30
AF connection cable,
3.5 mm stereo jack plug
to Texas connector
(supplied with the SI 30)
KK 20 extension cable
for connecting the
plug-in mains unit to
the modulator/radiator,
lengths: 1 m (KK 20-1)
and 7 m (KK 20-7), can
also be used with the
NT 20-4
SI 30
KR 20-7 RF connection
cable, 3.5 mm mono
jack plug, length 7 m
KR 20-015 RF connection
cable, 3.5 mm mono jack
plug, length 0.15 m, for
connecting clusters
SZI 30
KKY 20-015 4-way
“octopus” lead for
connecting the NT 20-4
to SZI 30 / SI 30 clusters
NT 20-4 plug-in mains
unit for up to four
SZI 30 / SI 30, European,
UK and USA versions
available
NT 20-1 Plug-in mains
unit for one SZI 30/
SI 30, European, UK and
USA versions available
MZT 100 anti-vibration
table stand
GZP 10 mounting plate
IZM 20 cluster
mounting kit, in-
cludes screws and
flange for com-
bining up to four
IZK 20 in a cluster,
3/8“ and 5/8“
internal threads
IZK 20 mounting
clamp for one
SI 30 / SZI 30,
3/8“ internal
thread
GZG 1029
swivel joint
IR Audio Transmission Technology | Modulators/Radiators