B&W 802D1 - How can I tame the brightness?

@OP It does sound like you have a room and setup problem - see https://www.stereophile.com/content/bw-802d-loudspeaker-measurements - coupled with the fact that your amplification is not the most synergistic match for 802Ds.

BTW, apropos the post above, while B&W make a big hoo ha about being used in Abbey Road, they are not studio monitors. Having owned a pair myself for hi fi purposes - and sold them due to their inaccurate frequency response - they are a very long way down the list of speakers I would use as studio monitors.

@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.

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".