Would like to get more bass out of my B&W 801 series 2 speakers

Ok I am going to throw out an option not yet considered... Due to the fact you listen a low levels, could the lack of apparent bass be due to the lack of appropriate low frequency equalization to make up for the low levels you listen? Think of the fletcher-munson curves and consider adding in some active equalization via DSP. Tweaking the response with some eq would go a long way towards resolving the issue. Given that you listen at low levels you probably are not using up the potential your current amplifier provides. That leaves headroom within the amplifiers performance envelope to apply some equalization. It will go a long way towards solving your issues with no real downside. If it turns out that you are pushing the amplifier beyond its comfort zone, you would likely already be aware of it. Also, you might want to verify that both speakers are wired in phase. Its so easy to make that mistake and cheap to fix. Taming the room reflections will clean up the 'smearing' of the sound that occurs with to many hard surfaces. Curtains, carpet, all will help. Hanging a decorative tapestry on the wall might help too. There are many ways to experiment with taming a bad room and I am sure you can make some headway by just experimenting with things you already own without spending money. Money of course fixes a lot of things, but there are other avenues to explore before resorting to that.

I found a set of speaker stands, they weigh 40# each and are designed in two pieces to fill bottom with sand.    Does anyone know anything about these?    They were commercially made as I have seen several of them over the years.   Good construction.

https://imgur.com/a/S8WsCjD

https://imgur.com/a/er6Zmaj

I think the stands are made by Arcici.    

@chessie I would like to second much of what

@livinon2wheels and others have stated above.

As you may be aware, the Series 2 was originally brought to market with an optional equalizer. The designer, as I understand it, considered the EQ essential to the speaker’s performance, because without it the ‘6th order Butterworth crossover’ was not implemented, and the 6th order Butterworth is advertised on the box the speaker came in. I suppose marketing thought the speaker on its own without the crossover was ‘good enough.’ Evidently, many customers thought so too.
All of which is to say that implementing a DSP is one way to augment the bass. As a Series 2 owner, I can attest to the rather anemic performance in the bass register, it just doesn’t seem to have much extension. What bass there is sounds good, but there just doesn’t seem to be as much as there should be.
For my part, I can que up my 70E Warfedales, with their 15” drivers, to get that next level of bass, although they lack the ‘punch’ of the 801’s.
Another thing I do is add a subwoofer in a corner of the room, even my mini-Velodyne works wonders.
The other thing I’ve often thought would improve their sound in my room was to get them up off the floor a bit so that the midrange and tweeter were closer to ear level. The original designer is on record as saying it wasn’t necessary to raise them, and that the only reason they offered the stands was for use in studios where the added height was needed for the sound to clear the mixing desk.
Anyway, those are my thoughts on the B&W 801 Matrix Series 2. I would still love to hear my McIntosh XRT-20’s in your space. They sound wonderful in my biggest room, which is much smaller than the room occupied by your 801’s.

The bass alignment filter is the solution. The speaker was designed to be used with it for the proper alignment. If you cant find a set of JPS golden flutes, the simply get a good parametric eq and duplicate the filters that the stock B&W filter implements. A web search will give you the exact parameters. If you want to go custom contact Marchand electronics to build one for you. Of course you can add a sub or get different speakers or amps but that doesn't solve the issue of the bass alignment. You can also bi amp and run the filter only on the bass amp leaving the kids and high school untouched. I had those speakers for 30 years so Im speaking from experience with my recommended solutions. Good Luck