SWR Sound SM-900 Bedienungsanleitung Seite 9

AA . X OVER OUT—(crossover outputs) You can bi-amp the
SM-900 by reassigning left and right power amps to high
and low frequencies: Use Stereo Mode; connect Hi and
Low to the L and R Effects Loop Returns {Y}; use Left and
Right Speaker outputs {U & V} to connect high- and low-
frequency speakers; adjust Crossover Frequency {I}, and
Balance {J} controls. NOTE: Only the Mono Effects loop
can be used when bi-amping the SM-900.
BB . BALANCED XLR OUTPUT— A fully featured, true elec-
tronically-balanced XLR jack for output to studio and live
performance mixing consoles. XLR controls:
• XLR PAD—Adjusts output level to accommodate a vari-
ety of sound equipment connections.
• LINE/DIRECT—Choose to include or bypass the SM-900's
Eq/tone circuits in the Balanced Output signal.
 LINE(Include EQ)
• DO NOT connect a speaker load with a
total impedance below the minimum
rating of your amplifier to prevent
damage to your equipment.
• ONLY connect speaker(s) with a total
power handling capacity that is no less
than the power output rating of your
amplifier to prevent damage to your
equipment.
• ALWAYS switch your system power
OFF before connecting or disconnect-
ing speakers.
• ONLY use unshielded speaker cable of
18 gauge or heavier (16 or 14 gauge)
for speaker connections. Shielded
instrument cable WILL NOT work and
may damage your equipment.
• ONLY connect one amplifier to your speaker
enclosure(s). Two amplifiers WILL NOT work and may
damage your equipment.
Use the impedance and power ratings on your amplifier
and speakers to determine if a particular combination of
speakers is appropriate for your amplifier. NOTE: All SWR®
bass speaker enclosures, as well as most others, are wired
in parallel (NOT in series), therefore, these guidelines
apply only to parallel speaker connections.
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DIRECT (Bypass EQ)
Speaker Guidelines
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Rear Panel
• GROUND / LIFT— Disconnects the ground connection
(pin-1) from the Balanced Output to reduce ground loop
noise generated from non-standard wiring. Normally,
leave this switch out:
GROUNDED (NORMAL)
XLROutputWiring(American Standard):
 1
 2
 3 Negative
The speaker illustration gives you the total impedance
load calculations for various speaker impedance combi-
nations (Ω=ohms). The ideal speaker load (total imped-
ance) is equal to the minimum impedance rating of
your amplifier.
impedance rating can overheat your amplifier and
cause damage. Operating above the amp's minimum
impedance rating while safe, reduces the amplifier's
maximum power output.
Something else to consider: You can obtain the same
group total impedance from different combinations of
speaker impedances (see illustration). If each speaker
in a group has the same impedance, each speaker will
receive the same amount of power from your ampli-
fier. However, if speaker impedances are not all equal,
the lowest impedances will get the most power. For
example, if you connect an 8Ω and a 16Ω speaker to an
amp output of 30 watts, the 8–ohm speaker will receive
about 20 of those watts (and be twice as loud as the 16-
ohm speaker). Take this into consideration when calculating
power handling capacities and when positioning your bass
speaker enclosures.
For an in-depth discussion of impedance and power rat-
ing issues, go to swrsound.com and click on "Support,"
then "Setup Tips"—an article by SWR® founder Steve
W. Rabe that ran in the August '92 issue of Bass Player
Magazine.
GROUNDLIFTED
Ground
Positive
Operating below the amp's minimum
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