Bang & Olufsen BeoVision Avant - Technical Sound Guide - Manual (Page 21)

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Setup: Sound: Speaker Groups: PRESETNAME: Advanced Settings: Subwoofer: Allpass Frequency
There is a first-order allpass filter in the
signal path of the subwoofer output.
This can be adjusted to better match the
subwoofer to the main loudspeakers in
cases where either the placement or the
phase responses of the loudspeakers
result in poor matching of the upper-
and lower-frequency components
through the crossover band. Since this is
a first-order allpass filter, its output is
90º out-of phase with its input at the
centre frequency displayed on-screen,
and approaches 180º out-of phase at its
maximum phase deviation (at 10 times
the filter’s centre frequency).
Range: Bypass, 20 Hz – 300 Hz.
Step Size: 1 Hz.
Setup: Sound: Speaker Groups: PRESETNAME: Advanced Settings: Bass Management: Enable Filtering:
SPEAKERROLE
The Enable Filtering setting for each
loudspeaker in your configuration
allows you to determine whether or not
the low frequency components of its
signal should be re-routed to the two
Bass Management low-frequency
channels.
Note that turning Enable Filtering to OFF
will not disable the potential of re-
routing the two Bass Management low-
frequency channels back to a given
loudspeaker using Bass Re-direction, as
can be seen in Figure 9 on page 18. If you wish to disable the entire bass
management processing, this should be
done using the Bass Management ON/
OFF parameter in the basic settings for
the current Sound Mode.
Note that initial settings of this menu
are automatically chosen based on
information from the Speaker Types
menu.
Setup: Sound: Speaker Groups: PRESETNAME: Advanced Settings: Bass Management: Panning:
SPEAKERROLE
The Panning setting allows you to
determine the relative distribution of
the low frequency components from a
given audio signal to the two Bass
Management low-frequency channels.
If the Bass Management Enable Filtering
for a given loudspeaker is set to OFF,
then the Bass Management Panning for
that output channel is irrelevant.
Setting this parameter to the centre will
result in equal levels being direced to
the internal left and right LFE channels.
Negative values result in the signal
being panned to the left low-frequency
channel. Positive values pan to the right. Initial settings of this menu are
automatically chosen based on
information from the Speaker Roles for
the current Speaker Group.
10 100 1,000 10,000
−200
−180
−160
−140
−120
−100
−80
−60
−40
−20
0
Frequency (Hz)
Phase (Degrees)
Subwoofer Allpass − Phase Responses
Figure 11: Phase response corresponding to
three values for the Allpass Frequency
setting, 20 Hz, 80 Hz, and 300 Hz.