6
5. CONNECTIONS
The connection cables which connect the amplifiers output and the speaker should be of
good quality, have sufficient conductor area and be as short as possible. The latter fact is specially
important when the distance is long and the load impedance low (4-8
Ω
). A cross-section of at least
2.5mm
2
is recommended for distances up to 10m; 4 or 6mm
2
for longer distances. Following formula
gives the required section, assuming 4% losses:
Length
in
m
Cross section in mm
2
=
⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯
Loudspeaker
Impedance
in
Ω
Always respect polarity. All connections are Speakon® type. The pin-out is indicated in the
diagram. The back panel connexion plate has a second Speakon® connector to connect
loudspeakers in parallel. With this manual you'll find a spare Speakon® connector.
6. RECOMMENDED AMPLIFIER
Following table shows the output power of the amplifier adequate to each acoustic system:
UMA112i between 350 and 700W
UMA115i between 500 and 1000W
UMA SB118i between 500 and 1000W
7. PRE-AMPLIFYING MIXERS
Avoid excessive gain adjustments in the equalizer or tone control sections.
8. PLACEMENT
Consider following general rules:
Place the acoustic enclosures on solid and firm surfaces. The Sub bass speakers will
prove more effective if placed on the floor horizontally, instead of flying, elevating or placing the unit
vertically. No obstacles should stand between the enclosures and the audience. The high
frequencies are very directive compared to the low frequencies, so that any obstacle will impair their
response. In case large audiences must be addressed, a better long distance sound propagation will
be achieved if the enclosures are flown high enough.
