A question on a B&W high pass filter

The short answer is that you probably won't damage your speaker (as long as you don't overpower them), but you also are not going to get much benefit. The filter is preset for the Freq. response of the 801. The variable filter allows you to set the response to the various models (See this link for detailed specs-http://kenrockwell.com/audio/b-w/800-series-bass-alignment-filter.htm). If anything , it might muddy the sound of the speakers. A third party manufactured these devices, and the parts are kinda crappy. If you really want to use the filter, I'd suggest selling this one and keep looking for the variable version with the DIP switches. Good Luck!

Jedinite-
Don't know what you are willng to spend, but your other options for better quality are-
1-Get the original, upgrade parts yourself if you have the expertise.
2-Look for a used Golden Flutes Filter specific to the 805- I haven't seen many for sale, and what people are asking is IMHO (upwards of $800) not worth it.
3-Look for a used Krell unit, which has internal switches to set for any matrix series model ( will probably run 1200-2000)

Jedinite

I 'm aware of the Anodyne unit, but have never seen one for sale. I'm currently using the Listen Up Maugham Box for my 801 SII, haven't updated my system picture though. Not positive, but I believe they only made it for the 801 model.

Oddly enough, when I got my 801's, the High Pass Filter came with the speakers, although they were supposed to be an extra. However, I was given the Filter for the 802. I used this off & on for years.

When I got the Maugham box, the improvement was subtle but noticeable-deeper, tighter bass, with an improved sense of bass tone and notes. I miss that extra depth without the filter.

Good luck.