PAS_SUB_SERIES.DOC
23/31
possible from the speaker-systems. When using the speaker-system as monitor-system make sure to avoid
feedbacks.
The speaker-systems of a PA-system are normally located left and right to the stage. Do not install the
speaker-systems on the stage, but rather on appropriate tables or platforms in front of the stage.
In order to produce a clear sound, the speaker-systems should be installed in a way that they throw the
sound over the audience's heads. A Full Range speaker-system should be installed at listeners' eye level.
Please refer to the safety instructions under Installation.
Loudspeaker combinations need to be installed bass-middle-high (from bottom to top). Make sure that the
membranes of all speakers are in one line vertically and horizontally. Only in this way all frequency ranges
are produced at the same time and without any time or phase delays.
Always install the speaker-systems in a way that a minimum distance of three meters to the audience is kept.
This is the only way to avoid hearing damage for unreasonable listeners. Block the area in front of the
speaker-systems with appropriate means.
Avoiding feedbacks
One of the most frequent problems when operating speaker-systems are feedbacks. They can be
recognized by howling and growling loudspeakers. Feedbacks are created then a signal is recorded by a
microphone, amplified, played back by a loudspeaker and then again recorded by the microphone.
The prerequisite for feedback is that the played back signal is louder than the original signal. A feedback
never cover the whole frequency range but only one overboosted frequency.
Make sure that you install especially the monitor-speakers so far away from the microphone that another
recording of the microphone signal is impossible.
Extreme levels like feedbacks, bass-hum or the beats of a dropping microphone can destroy the
loudspeakers within very short time and produce immediate hearing damage. Such extreme levels must be
avoided at any rate. We recommend to use appropriate equalizers and Compressor/limiters.
Installing the speaker-cables
Connect the speaker-systems among each other using the inputs and outputs. Connect the cable of the first
speaker-system with the Speaker-socket Output CH-1 and Output CH-2 of the amplifier. The signal will be
transmitted to the individual speaker-systems.
Always treat the cables carefully and protect them from damages during transportation.
Install the cables always in a structured way and protect them from damage.
The cables must be installed in a way that no person can stumble over them. Always fix the cables with an
appropriate tape.
Both cables should be of the same kind.
Both cables should have the same length.
Both cables should be installed directly (no loops, S-shaped overlengths)
Always install the cables far away from power cables (never closely parallel)
Never put heavy objects like speaker-systems, flightcased etc. on cables.
Never wind up cables tightly around the elbow, but rather sleek with an interior diameter of 20 to 30 cm.
Overhead installation
If this speaker-system will be installed in a mounting height higher than 1 meter (e.g. on the stage, on a
stage element or on a framework) we speak of overhead installation. For overhead installation, the speaker-
system must always be secured with an appropriate secondary attachment.
Safety-ropes are allowed as secondary attachment for all speaker-system up to a maximum weight of 60 kg.
Heavier speaker-systems must be secured via appropriate measures based on individual calculations.
