HHB comm CIRCLE SERIES - Manual (Page 13)

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Figure 6 5.1 mode - method 1 (switch in 5.1 position)
In the second connection, method 2, all the monitor signal
outputs (normally left, centre, right, left surround and right
surround) are connected to the inputs on the HHB Circle 1,
and the outputs are fed to the loudspeakers. This method
filters the low frequencies (below 120Hz) from the
loudspeaker feeds. The sub-woofer is always driven from the
SUB input - it receives no low frequency information from
the other five inputs. This connection method is widely used,
since by removing the extreme low frequencies, the five
full-range loudspeakers can be utilized more efficiently. This
method of signal connection makes the most of the
Circle 1’s high quality filters.
Figure 7 5.1 mode - method 2 (switch in 5.1 position)
Using the HHB Circle 1 in ‘B mode’, the bass frequencies are
extracted from the left, centre and right inputs and not from
the SUB input. The left and right monitor signals (or left,
centre and right) are connected to the XLR inputs and the
bass (below 120 Hz) is filtered from these signals, equally
mixed together and fed to the sub-woofer. The rest of the
frequency spectrum from these inputs is output from the left
and right (or left, centre and right) XLRs as normal for
connection to Circle 3 or Circle 5 speakers. This mode allows
optimum flexibility with both stereo and LCR source formats.
Figure 8 B mode (switch in B position)
The three controls on the HHB Circle 1 allow simple
configuration for each particular surround setup. An input
sensitivity level adjusts the volume of the sub woofer, without
affecting any of the other signals that may be passing through
the filter stages of the unit. The bass boost control provides
approximately 10dB of boost in a half octave centred at 33Hz.
The function of this is to compensate for the frequency
response of the human ear when listening at low levels. The
boost control should be normally be set near minimum when
listening at mid to high levels, but the boost level may be
increased as the listening level is reduced. Please note that
the HHB Circle 1 is not designed to be used at full boost and
very high level. Some user adjustment is required to obtain
the optimum balance between the preferred sound and power
handling / power capacity of the system. The phase control is
provided to enable smooth integration of the Circle 1 with
other loudspeakers in the surround system; this control alters
the phase of the sub-woofer signal through 180°, enabling
the sub-woofer to blend with the other loudspeakers in the
system, whatever your monitoring requirements. The phase
control should be adjusted to obtain the best, smoothest
balance between the deep, mid and upper bass along with the
mid and high frequencies in the Circle surround system, with
the entire system installed and in the correct positions.