Sennheiser SZI 1029 - Manual (Page 4)

SZI 1029
When planning and installing an IR system you have to pay attention to use the cor-
rect terminating impedance for the radiator chains. Sennheiser IR modulators have
an output impedance of approx. 50
Ω, whereas the radiators have a much higher
input impedance of > 5 k Ω. This “headroom” allows you to connect many radiators
without any problems. In RF transmission, the output impedance has to be termi-
nated with approximately the same input impedance. If this is not done, refl ections
may occur at the end of the RF chain and disturb the transmission. So, for reasons
of reliability, the end of an RF chain should always be provided with a 50-
Ω termi-
nating impedance. Please note that you should not use “T” adaptors in your RF
chain as this would halve the terminating impedance.
For large installations you should use both RF outputs of the modulator and create
two RF chains. This not only increases reliability but also avoids cancelling out
between radiators due to time delay. Please refer to the chapter “Planning Theory”
for more information on time delay and cancellations.
SZI 1029-10
The SZI 1029-10 is Sennheiser’s most powerful radiator. 264 diodes in 24 inde-
pendent groups provide an average radiating power of 10 W. The SZI 1029-10 is
connected and operated like the smaller SZI 1029. The radiator’s higher power is a
special asset when it comes to covering large halls or auditoria with high ceilings,
especially when a large number of channels are used.
The SZI 1029-10 is also interesting for rental companies: due to the higher radiating
power less radiators are required and IR systems can be set up and taken down
again more quickly. Sennheiser high-power radiators are convection cooled so no
cooling fans are used which could cause disturbing noises.
MONO MULTI
CHANNEL
OUTPUT INPUT
MONO MULTI
CHANNEL
OUTPUT INPUT
Daisy-chaining the SZI 1029
50
Ω
50 Ω
50 Ω
Risk of cancelling out!
SZI 1029-10 radiator
IR Audio Transmission Technology | Modulators/Radiators