B&W Bass Alignment filter Adjustments

Try the DIYaudio forums, they have a lot of very knowledgeable people there but in the meantime I found this link online. I suggest however to measure and do whatever you need to do rather than attempt to replicate any particular setting verbatim.

Keep the rapid rolloff in mind though, as it seems that is necessary to prevent the cone from over-excursion. Also, if you are going to add a sub anyway, plug any ports before measuring and configuring.

https://mail.kenrockwell.com/audio/b-w/800-series-bass-alignment-filter.htm

Boost maybe at 28hz  steep cut 20hz

Do no harm.  Get rid of it.

@xenolith The speakers really do need the alignment filter to sound as intended, but those functions are best done with a miniDSP these days. 

Given how different speakers sound in the room though, trying to replicate the original values may not be as useful as measuring in the room and tuning to optimal from that.

MiniDSP    Thanks