Bowers & Wilkins DB1 manual Low-Pass

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°.

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