Bowers & Wilkins DB1 - Manual (Page 11)

11
ENGLISH
Low-Pass
Enables the DB1’s low-pass filter characteristics to be
specified. The characteristics of a subwoofer low-pass
filter define how the subwoofer integrates with the main
speakers in the system.
Note: In home-theatre systems, where the subwoofer
is connected to an LFE (low frequency effects)
output, no low-pass filter is required because filtering
is inherent in the home theatre signal decoding.
The low-pass filter menu options are User and
Speaker. Although you may use the buttons and
display to select the
Speaker option, you cannot
configure it here and the default is a flat response (ie
no filter), indicated by the word
None. However, if
the main speakers to be used with your DB1 are an
existing Bowers & Wilkins model, you may configure
the
Speaker option using the SubApp™ program by
selecting your speakers from a drop-down menu. The
Speaker low-pass filter gives a more accurate blend
between the DB1 and your main speakers than can be
achieved with the
User option. The default is User.
Selecting User provides the option of specifying
a custom low-pass filter. Select User if your main
speakers are not Bowers & Wilkins or if you are not
using the PC SubApp™ program. The low-pass filter
User parameters are Freq(uency), Slope and Phase.
Select
Freq to set the low-pass cut-off frequency of
the filter to match the high-pass –6dB cut-off frequency
of the main speakers. For Bowers & Wilkins speakers,
this can be found in the technical specification under
Frequency Range. If the specification of your
speakers only quotes a –3dB frequency, multiply
this by 0.6 for closed-box systems and by 0.7 for
vented-box (reflex) systems to get a close enough
approximation to the –6dB frequency. The default is
80Hz.
Select Slope to set the low-pass filter slope of the
filter to match the high-pass roll-off slope of the main
speakers. If the slope is not given in the speaker’s
specification, select 24db/Octave if the main speakers
have a “reflex port” and 12dB/Octave if they do not.
The default is
24dB/octave as the majority of Bowers
& Wilkins speakers are vented-box types.
Select Phase to adjust the phase integration of the
DB1 and the main speakers. Adjusting the phase can
be useful to overcome audible problems of integration
between subwoofer and main speakers, usually with
room acoustics at their source. Set the
Phase initially
to 0° for the 24dB/Octave option and 180° for the
12dB/octave. Compare these settings with the other
options on a variety of music with significant bass
content and choose the option that gives the fullest
bass. The default is
0°.