Bowers & Wilkins PV1D User Manual page 12

Audio
Inputs
Speaker
List
Presets
Low-Pass
User
List
Speaker
Modifies the PV1D's response to blend optimally with
the main speakers. It is important that you configure
this section for all applications.
1. For 2.1 stereo applications not using a surround
processor, a low-pass filter is calculated to match
the subwoofer to the natural bass response of the
main speakers.
2. When using a surround processor, the internal
low-pass filter of the PV1D is not required,
but its response still requires adapting to the
main speakers. In addition, you should use our
recommended settings for certain parameters of
the processor. See also Section 6 – Configuring a
Surround Processor.
The menu options are User and List.
Selecting List advances to the Choose Speaker
screen where you may select one of a number of
specified Bowers & Wilkins models. If the name of your
main speakers is listed here, simply select it and all
parameters will be set automatically.
At the top of the list you will initially see the option
None. The PV1D SubApp™ program will allow further
Bowers & Wilkins models to be selected from a drop-
down list and any model selected there will replace
None.
12
M-1 (2011)
Choose Speaker
None
M-1 (2011)
M-1 (2005)
686
685
Certain powered speakers, such as Panorama. already
include subwoofer filtering. For such main speakers,
select List then None and do not overwrite None from
SubApp.
Selecting User provides the option of specifying
a custom low-pass filter. Select User if your main
speakers are not listed either internally or within
SubApp™ or are not a Bowers & Wilkins model.
The default is Speaker and the default speaker is the
first named on the list after None.
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.
User Low-Pass
Freq
80Hz
Slope
4th-order
Phase
0deg
Low-Pass Phase
0 deg
90 deg
180 deg
270 deg
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 4th-order if the main speakers are
vented (ie have a reflex port) or have a passive radiator
(sometimes called an ABR) and 2nd-order if they do
not. The default is 4th-order as the majority of Bowers
& Wilkins speakers are vented-box types.
Select Phase to adjust the phase integration of the
PV1D 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 4th-order option and 180° for the 2nd-
order. 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°.
Low-Pass Slope Low-Pass Freq
2nd-order
80
4th-order
Hz