d&b Y8 - Manual (Page 7)

2.3.1. Controller settings
For acoustic adjustment the functions CUT, CPL and HFC can be
selected.
CUT circuit
Set to CUT, the low frequency level of the cabinets is reduced. The
Y8/Y12 array is now configured for use with the d&b Y-SUB or
J-SUB subwoofers.
CPL circuit
The CPL (Coupling) circuit compensates for coupling effects
between the cabinets of an array. CPL begins gradually around
2 kHz, with the maximum attenuation below 100 Hz. As coupling
effects increase with the length of the line array, the CPL circuit can
be set to dB attenuation values between 0 and –9. With higher
attenuation values the corner frequency of the filter shifts towards
lower values.
Positive CPL values create an adjustable low frequency boost (0 to
+5 dB) and can be set when the system is used in full range mode
without subwoofers.
Note: Make sure that all cabinets within the line array are
operated with the same CPL setting.
HFC circuit
Selecting the HFC (High Frequency Compensation) circuit
compensates for the loss of high frequency energy due to air
absorption when loudspeakers are used to cover far field listening
positions.
The HFC circuit has two settings (HFC1 and HFC2) for different
distances the cabinets need to cover. The settings should be used
selectively; HFC1 for cabinets covering distances larger than 25 m
(82 ft) and HFC2 for those covering distances larger than 50 m
(164 ft).
The compensation is adjusted for a typical relative humidity of
40 %. With lower humidity the absorption by air increases
therefore the distances where the respective HFC setting provides a
correct equalization are shorter than indicated above.
Using the HFC function provides the correct sound balance
between close and remote audience areas, whilst all amplifiers
driving the array can be fed with the same signal.
Frequency response correction of CPL circuit
Frequency response correction of HFC circuit
d&b Y8/Y12 Manual 1.1 en 7