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

OP, Have you ever measured the SPL out of your room / speakers?  If not, try to get some measurements to determine if the bass responses were indeed lacking and, if so, how far is it from the targeted or the factory published level.  REW is free but need some training and experience.  I would suggest getting either Wiim Pro or Pro+ to do the room correction and EQ.  While going through that process, you will be getting the current measurement out of the speakers and room.

The coveat is the internal mic of iphone or androi phone may not up to task and a mic such as Umik 1 is recommended.

yags1 probably has it with the Sound Anchors stands.  Or, possibly Gaia Footers or Townshend.  So many chase around trying to fix what cannot be fixed until stability issues are addressed.  This also applies to equipment.

The Sound Anchors, Gaia or Townshend will not provide more bass, but rather better bass.  They will also clean up the mids and highs and organize the sound stage.

Oh, and yes the windows are quite reflective of sound and not in a good way.

Cheers

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.