K.M.E. VSS 18, User Manual

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14. PA systems active: Set-up, connection shemes & system versatility
14.1 Set-up PA systems
Note!
Please note specific and useful set-up of a first-class loudspeaker system. A universal
statement about the correct (standard)-adjustment and set-up of PA systems is
impossible, because each reinforcement is bound to a different place and has always
different features.
When using high stands or distance rods for top parts the user has to guarantee the
stability. Please use just certified mounting material when installing the systems to
guarantee the safety. Depending on the features of the area/room to be reinforced the
top unit(s) can also be swiveled a bit horizontally and tilted vertically to reduce reflections
(on walls + ceilings) and interferences and therefore achieving a better utilization of the
sound energy.
If covers are opened or sections of casing are removed, except where this can be done
manually, live parts can become exposed. If it is necessary to open the unit this must be
insulated from all power sources.
Please mind that it is not coming to a ground loop during cabling of the system. If it
comes to deep-frequent hum switch the Ground-Free to „Free“. Always use balanced
signal cables if possible. Do not mask or detach the conducter connection on the mains
plug!
Danger!
High loudspeaker levels can cause permanent hearing damage. You should therefore
avoid the direct vicinity of loudspeakers operating at high levels. Wear hearing protection
if continuously exposed to high levels.
When should I choose a directional or omnidirectional dispersion in the low-frequency
range?
Each direct radiating subwoofer has a omnidirectional dispersion in the low-frequency range.
Depending on local conditions it can comes to spatial interferences. The cardioid dispersion
pattern resulting from this approach avoids unwanted energy behind the system that greatly
reduces the reverberant field at low frequencies and provides the greatest accuracy of low
frequency reproduction.
The directional (cardioid) dispersion offers a lot of significant advantages in the all-day
reinforcement work. The highest sound energy will be radiated just in the front very
homogeneously, on the side the damping increases and achieves on the rear side a very wide-
range excellent damping quality at all frequency range of more than 20 dB. For the first time the
whole frequency band from bass to mid/high can be adjusted to the audiences’ area. Especially
in an acoustical different location like marquees, glas buildings, open airs with level restriction or
in halls with large reverberation time the cardioid technology is an advantage. Even at very high
volume levels develop considerably less wall- and ceiling-reflection. The complete bass
reproduction explicitly gains in pressure and precision.