@mylogic you would certainly be thinking outside the boxes if you attempted to turn a set of 800 series B&Ws upside down, seeing as there is no flat surface on the head unit of the speaker

Maybe hang them upside down from the ceiling like we used to do with the old Series 1 Bose 901s

that might be more difficult than hanging a ceiling fan:)

802 D1s need thoughtful placement to perform best. They are not bright and fatiguing in a non-reflective room with the right width and toe angle (zero or near zero). 

Placed in a small room with straight, on-axis toe and they can certainly sound boosted in the upper mids/low treble. Keep in mind that B&W voices their speakers knowing that the vast majority of owners will not have them many feet out into a room but instead have them within a foot or two from the forward wall. The resulting  boundary gain will go a long way to offsetting otherwise perceived brightness. 

If you have tried everything but still dislike them, what is left to do other than cut your losses and sell them? 

If you decide that you can’t live with them I’d suggest looking at Vandersteen upper range of speakers. They might be more to your liking

My 802 D2 was a little tight and sharp on the top end it wasn’t bad. I did what Bill Steveson suggested about 5 years ago. I used 2 JL Audio E 112 sub woofers with a JL Audio CR-1 and the system sounds great for my ears. It took me a while to get  the subs positioned correctly but it was worth it my room is 14’ x 26’. 

Well, one could always make a steel cage to house the 802s - a bit like Roksan did with the original Darius loudspeakers :))

BTW, joking aside, studio monitors usually have a specific orientation unless they are symmetrical such as in a d'apolito configuration e.g. many Focals, or where they mount the tweeter beside the midrange as in the Neumann KH 310.

I've never seen anyone use a pair of Yamaha NS 10s upside down in the studio - and that is a speaker that defines "bright".

I’m gonna get trashed for this, but damn, it works!  
The 802’s are equipped to biwire.  Single wire them instead, using the woofer input, the lower pair.  Connect a jumper between the upper binding post ground (minus, or black) and the lower binding post ground.  Instead of using a jumper between the two positive terminals, use a 2 ohm, 10 watt resistor. This will lower the output of the midrange and tweeter drivers by a small amount.  Too much?  Use a smaller value resistor, they’re available in increments of ohms.  I suggest a high quality resistor such as those by Dale, Caddock, or Vishay if you like the effect.  Resistors are comparatively cheap and using them won’t harm anything and is easily reversible and amenable to experimentation.  Just so you all know, Wilson offers the option of switching external resistors to tailor the high frequencies to taste as does Magnepan. In fact, any speaker that offers high frequency tailoring uses some variation of this method.

I fought a brightness battle with my B&W 801 Matrix speakers. I then fought a similar battle with my Wilson Sasha 2s. I now love my Rockports. Save yourself the battles. Sell them and find a sound you love.

+1 find a sound that you love.  A speaker that will draw you into the music, a joyful place like no other.  Move on, this one ain't it.  

You haven't mentioned any room treatments. For sure I would treat the first and secondary reflection points.  I've used GIK art panels and further added Owens-Corning insulation to this with excellent results.  My hearing is sensitive to high frequencies anyhow and this made a big difference for me.  This will improve the sonics in just about any room and no matter if you change speakers, it will improve your sound.  Also agree with the others regarding toeing the speakers straight out and not in.  

You might look at using Marantz gear with the B&W. Marantz lean toward the warm side and can help tame those speakers 

Op Audioquest waters interconnect are on the thin side, try Columbia Audioquest or maybe Cardas. Cerious graphene cables might work.you can audition them too.

What power cables are you using?

DSP ? or send one to Danny @ GR research he can fix them  see if he allready has a fix for that speaker? i just watched 2 YT vids about him fixing a pair of $27.5 K Wilson watt puppies! wow $27 K and they are real POS needing a LOT of re-work to be optimized!  weird! 2 part YT video! 
https://youtu.be/Tma9jFZ3-3k?si=GcgkV3o2Ep5KvSaA
https://youtu.be/pIt2pcQvf6M?si=V-nu0XtiWsQXfQlx
his kit for B& W is   
https://youtu.be/wmmw8QlThPk?si=Svwa4ln20v7rZkVn
only 54 parts! needed a lot of fixing ! LOL 

B&W 802 S2 Upgrade Kit (Pair)

$525.00–$692.00

The price is per pair.

This upgrade kit fixes a number of issues and greatly improves the quality of the crossover over the stock network.

The kit includes all of the necessary crossover parts, along with wire, solder, heat shrink and a set of tube connectors.
A new crossover/mounting board is not included.

Bass-Alignment Filter: B&W’s “bass-alignment filter” is compatible with our upgrade, as it only addresses frequencies below 100Hz. however we do not recommend it as it is more of a “band-aid” than an actual fix for poor room acoustics, while also robbing clarity from the midrange and treble.

I think you should replace the speakers or you spend all of your time acquiring components, etc to counter a specific deficiency. 

B&W upgrade kits….

These speakers and all the tweaks offered by other forum members (and now upgrade kits) suggests there are just some flaws with the design. Is this tweaking and upgrade path normal with speakers?

Are the 802’s (for example) the equivalent of the original Linn turntable that requires (in most cases) constant upgrades or fettling to please their owners?
Just adding the simile because the Linn comparison evidence is out there for all to see, and often on this forum.

Saying that, l have never heard of so much frustration or irritation with any specific model of speaker before. Every brand l have ever bought has never needed to be rewired or altered unless cosmetic repair or treatment was required.

I would just trade or sell these B&W’s on if they are that bad, but for me an audition first would have avoided all the fuss. Throwing more money at electronics is not always the best option.

There are many types of speakers which can be overly bright; ribbons, horns, etc….. 

One thing to consider is parametric equalization (PEQ) or low pass filters applied in the digital domain before your DAC.
Additionally it's desirable if you can achieve a "Harman tilt" or "Harman target curve" for a more enjoyable listening experience.

We have a video which overviews one way of doing using miniDSP Device Console  
 

@onehorsepony, 

I had the same issue with the entire B&W 800 series line and ended up purchasing Aerial Acoustics some 30 years back and been there ever since.

I would check into other speaker lines and if possible check in room for audition.

Good luck and happy listening!

DeeCee

Did you ever consider contacting PS Audio: Since you own their premiere product, I am sure Paul & his customer service  dept would be most happy to help you.
 

I am not sure how long you have owned the 802D1’s, but it could be you just don’t like them and the issue is not fixable, PS Audio and B&W may not be a good match. your room maybe overly bright. Like everything in audio, there are too many variables.

You don’t say what the rest of your gear is. 
 

b&w’s are highly revealing of components that add noise and distort highs. 

you likely need better gear especially better cables. 

EQ. Acoustic treatments. But different speakers.

@ghdprentice   I have a newly purchased pair of 22 year old Sonus Faber Cremonas and with my McIntosh 2200 amp they can still screech when fed certain cds (vinyl seems to not be a problem). The older models may have a warmer tone, but they're still honest & occasionally unforgiving, depending on the amp you've paired them with.

I can't listen to B&W diamond series at all. The tweeter's natural resonance is 35khz, breakup frequency is 17.5khz so playing anything with cymbals or bells I'll get ear fatigue (if not intense ringing) in less than 10 minutes' time.

Bright is not a word I would use to describe B&W speakers, I have sold lots of them and own a few pair, not what the OP has, the speaker is last in the chain of audio

it could be a system thing that just doesnt work, room issues, isolation issues etc

Trial and error is the only way. my take is if one cant get the sound they are looking for with basic cables like Gator cable....STOP right there. I have heard very expensive cables that just plain dont sound musical, not saying they cant

but start with the basics, try basic cables and different sources if you can and see where it goes.

Why do you say the following?

 a gross mismatch of preamp/amp and speakers.

What is this based on? any facts to support your claim?

Nah, just a WAG based on your description of the sound you are getting, i.e. too bright and poor bass, etc. If my use of the word 'gross' offends you (and it must since you seem not to focus on any of my other posts) then I will gladly admit it was probably a superlative and change it to 'minor'. That help?

IF the speakers are properly set up in your room, something that was suggested in many posts in your 2 threads, by myself and others, IF the electronics are high quality and 'matched' properly, then, the only thing left is the speakers which must be deficient for your purposes. If the speakers are not deficient for your purposes then you really have a conundrum. Good luck solving it. 

B&W speakers with the diamond tweeter are very bright to my ears. The solution is to use a warm preamp and amp combo. A number of years ago I heard one of the larger pair at Best Buy Magnolia with a Rotel preamp and amp that sounded very good. The very reasonably priced Rotel components actually sounded better than the pairing with high priced Mac tube monoblocks. B&W and Rotel are closely aligned companies, and B&W has been known to voice their speakers with Rotel components. If there is a store near you I would call them and see if they have the pairing for a demo. Costs you nothing to hear for yourself.

B&W speakers with the diamond tweeter are very bright to my ears. The solution is to use a warm preamp and amp combo. A number of years ago I heard one of the larger pair at Best Buy Magnolia with a Rotel preamp and amp that sounded very good. The very reasonably priced Rotel components actually sounded better than the pairing with high priced Mac tube monoblocks. B&W and Rotel are closely aligned companies, and B&W has been known to voice their speakers with Rotel components. If there is a store near you I would call them and see if they have the pairing for a demo. Costs you nothing to hear for yourself.

Stay away from noisy graphic EQs and get a Schiit Loki. Four bands, under $200.

Steve Guttenberg has one and loves his.

B&W upgrade kits….

"These speakers and all the tweaks offered by other forum members (and now upgrade kits) suggests there are just some flaws with the design. Is this tweaking and upgrade path normal with speakers?"
yes tweaking is VERY normal now for many speaker brands and models no the comparison to some turntable w/ issues is irrelevant . there are experts who have done the research and come up w/ fixes when  you have a speaker you like it makes sense to resolve some issues it has and keep it . sometimes it is cheaper than buying a better model sometimes not . but at least you know it is the best it can be lets say you buy a upgrade model it may have issues too!