QSC CMXa Série Mode D'emploi page 7

Features and Setup
Attenuation Control Security Plate
The Attenuation control security plate (— Figure 4) provides protection against accidently adjusting the Attenuation controls on the amplifi er face.
Attach the plate, after making fi nal adjustments to the Attenuation controls, by sliding the tabs into the installation slots. Secure in place with the
attachment screw.
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— Figure 4 —
Setting the Mode Switches
The CMXa has mode switches for STEREO, PARALLEL INPUTS, or BRIDGE MONO modes. Each channel has independent clip limiting and low
frequency fi ltering.
Clip Limiter
What it is
When the audio signal drives the amplifi er's output circuit beyond its power capability, it clips,
fl attening the peaks of the waveform. The clip limiter detects this and reduces the gain to
minimize the amount of overdrive. To preserve as much of the program dynamics as possible,
limiting reduces the average program level until peaks barely clip.
Each channel has its own clip limiter, and you can switch it on or off independently, as shown
in — Figure 5.
— Figure 5 —
When to use it (or not)
When driving full-range speakers, clip limiting reduces high-frequency distortion caused by bass overloads. It also protects higher frequency drivers
from excess overdrive and harsh clipping harmonics.
When driving subwoofers, some users let the amplifi er clip without limiting because it gives extra "punch" to kick drums and similar sounds.
CAUTION: In bi-amp systems, excessive limiting will affect the frequency balance.
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