PROTECTION
A protection circuit is built into the C300z to stops, and is characterized by a O� at-top� ap-
pro tect the high-frequency compression driver pear ance to the waveform when viewed on an
from excessive power. When the pow er to the HF oscilloscope.
driver approaches the max i mum, the power de-
liv ered to the driv er is mo men tari ly reduced.Normal Sine Wave Signal :
CAUTION: The protection
cir cuit is de signed to protect
the HF driver under rea son able
and sen si ble conditions. Should
you choose to ignore the warn-
ing signs (i.e., fre quent clip
LED indications, ex ces sive dis tor tion), you can Clipped Sine Wave Signal
still damage the speak ers in the C300z by over-
driving them past their recommended am pli Ţ er
power-han dling rat ings, or past the point of am-
pli Ţ er clip ping. Such damage is beyond the scope
of the war ran ty.
Amplifier Power
Clipping interrupts the motion of the trans-
We give you three power-handling num bers for duc er, creating distortion and ex ces sive heat in the
the C300z: rms (continuous), mu sic, and peak. So driver, which can damage it over time.
how much power do you re al ly need to drive the Some folks think that if they use a power am-
C300z?
The answer to that question depends on what pli Ţ er whose power rating is below the maximum
type of pro gram material you are run ning through power-handling rating of the loud speak er, then
the system and how loud it needs to be.they canOt possibly dam age the loudspeaker. But if
Some audio signals have lots of mo men tary the ampliŢ er is driven into clipping, even a lower
peaks whose amplitudes extend far above the power am pli Ţ er can damage the loudspeaker.
av er age overall level of the pro gram. Percussion in-The bottom line is that to prevent dam age to
the loudspeakers, you must have a prop er ly op er -
stru ments are a good ex am ple of this. Other types at ing sound system. Proper op er a tion of a sound
of signals, like highly compressed rock mu sic, have system includes being aware of the types of audio
a high er average signal level with fewer peaks. signals being re pro duced, controlling the output
Speech reinforcement requires less power overall, levels ac cord ing ly, and operating all the devices in
but involves large moment-to-moment vari a tions the system so that no clipping occurs with in the
in level.signal chain.
Assuming you want to use the full ca pa bil i ty
of the loudspeaker, and the program contains at
least some momentary peaks, we recommend that RIGGING
you use an ampliŢ er that is rated at twice the con-The C300z cabinets are Ţ tted with ten rig ging
tin u ous power rating of the loudspeaker (into 8 points as shown in the di a gram on the previous
ohms). For the C300z, this would be 300 watts x 2 page. These are M10 inserts. M10 thread ed eye-
= 600 watts per channel into 8 ohms. This in sures bolts (M10 x 1.5 mm x 20 mm) are avail able to Ţ t
that the ampliŢ er can reproduce peaks that are 6 dB in these in serts (PA-A1 Eye bolts).
higher than the con tin u ous (rms) power-handling WARNING: Never at tempt to
rating before clipping oc curs.suspend the C300z loudspeak-
ers by their handles. If you
Preventing Loudspeaker Damagewant to sus pend them, use the
Speaking of clipping, this is likely the num ber rigging points only. Con sult a
one cause of damage to loud speak ers. Clipping oc-pro fes sion al rig ger or struc tur al
curs when the signal at the output of any device en gi neer prior to sus pend ing loud speak ers from a
in the system (not just the ampliŢ er) reaches its struc ture not in tend ed for that use. Always know
maximum level. The input signal to the device the work ing load lim it of the struc ture sup port ing
may continue to increase, but the output simply the loud speak er ar ray. Al ways make sure that the
rig ging hard ware minimum rat ing is at least Ţ ve
times the actual load.
7 |
ACEC
