00063757.DOC, Version 1.0
19/28
4. CONNECTING THE SPEAKER
Choosing an appropriate PA amplifier
This speaker system must only be connected to an appropriate power amplifier. The amplifier power must
correspond with the speaker system power. An amplifier with too little power can also destroy a speaker
system with a higher power range.
Before starting with the installation, you must clarify how many speaker systems you would like to install in
the room.
In order to increase the sound pressure level two speaker system pairs should be connected with the power
amplifier. Please note that the impedance is only half the value when you connect two speaker systems with
one channel of the power amplifier. Please make sure that the power amplifier is qualified for this operation
mode.
When connecting further speaker system pairs (e.g. 3 pairs) to the same power amplifier, the impedance
lowers even further. You must always make sure that the power amplifier is qualified for the new impedance.
If the impedance of the speaker system is lower than the lowest allowed amplifier impedance, the amplifier
and the speaker systems may be damaged.
Furthermore, you must define the operation mode for your system. If the power amplifier is to be used in
stereo mode, the power is lower as in e.g. mono bridged mode.
The following descriptions refer to OMNITRONIC power amplifiers. You may also use other appropriate
power amplifiers.
Operating modes
The most frequently used operating mode of an amplifier is stereo operation with 4 speaker, where both
channels are operated independent of each other.
In parallel operation the amplifier can be operated in mono mode, i.e. via one input channel. The voltage
remains the same, the current is doubled. Consequently, the output impedance is limited to the minimum
value of one individual channel.
In bridge operation the amplifier can be operated in mono mode, i.e. via one input channel. The voltage is
doubled and subsequently also the output impedance. For stereo operation two amplifiers are needed.
Always make sure the power amplifier's selector switch for the operating mode is set accordingly. Please
also refer to the diagrams at the end of this user manual.
Example for the calculation number of speakers/impedance
Number of speakers
Impedance
1 speaker at 8
8
2 speakers at 8 each 4 (parallel)
2 speakers at 8 each 16 (in line)
3 speakers at 8 each 2.66 (parallel), only for amplifiers capable of handling 2
3 speakers at 8 each 24 (in line)
4 speakers at 8 each 2 (parallel), only for amplifiers capable of handling 2
The input impedance of the speaker systems should at least be the same or even higher than the output
impedance of the amplifier.
