Hklai:
According to my B&W 800 Series Variable High-Pass Alignment Filter manual, the filter has 10 switches (numbered (from bottom to top) 1 through 0, for each channel. The Matrix 801 speaker switch position for each speaker is listed as follows:
Switches 2, 4, 7,and 9 on. The other switches are in the off position.
The positions for the Matrix 804 are listed as:
Switches 2, 3, 5, 7, 8 and 0(10?) on.
I have B&W 808's which are not listed in the manual. If someone knows the correct positions for these speakers, please post.