d&b audiotechnik M4, Руководство по эксплуатации

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Controller settings
For acoustic adjustment the functions CUT, HFA and CPL can be
selected.
CUT circuit
Set to CUT, the M4 low frequency level is reduced. The M4 is now
configured for use with the Q-SUB, J-SUB or d&b C-Series subwoofers.
HFA circuit
-5
0
5
10
-10
-15
-20
-25
-30
20 100 1k 10k 20k
Frequency response correction of HFA
circuit
In HFA mode (High Frequency Attenuation), the HF response of the M4
system is rolled off. The HFA circuit provides a natural, balanced
frequency response when a cabinet is placed close to listeners in near
field or delay use.
High frequency attenuation begins gradually at 1 kHz, dropping by
approximately 3 dB at 10 kHz. This roll-off mimics the decline in
frequency response experienced when listening to a system from a
distance in a typically reverberant room or auditorium.
CPL circuit
Frequency response correction of CPL
circuit
The CPL (Coupling) circuit compensates for coupling effects between the
cabinets when building closely coupled arrays. CPL begins gradually at
1 kHz, with maximum attenuation below 400 Hz, providing a balanced
frequency response when M4 cabinets are used in arrays of two or
more. The function of the CPL circuit is shown in the diagram opposite
and can be set in dB attenuation values between –9 and 0.
Positive CPL values create an adjustable low frequency boost (0 to
+5 dB) and can be set when the M4 is used as a full-range PA speaker.
For a single cabinet in free space conditions a value of +3 dB is
recommended.
Operation with E-PAC
Selecting M4 mode enables the E-PAC to drive one M4 loudspeaker.
LO IMP mode configures the E-PAC to drive a maximum of two M4
loudspeakers with a 6 dB reduction in input level to the loudspeakers.
For acoustic adjustment the CUT and HFA settings are available. The
characteristics are described in the previous section "Controller
settings”.
M4 Manual (1.8 en) Page 6 of 10