"Those 800 Diamond's were easily the best sounding B&W speakers I've ever heard."
Krell man, while you thought they were the best B&W speakers yet how do they stack up to other speakers you have heard?
Goatwuss,
I did not hear the 800D but I have demoed the 802D at length a number of times (also owned 803s) and I demoed the 802diamond for a few hours.
I heard the 802D and 802Diamond in different rooms with different pre-amps (audio research, classe') but both demos used Classe' amps (and I used the same music). I felt the 802diamond had better impact on bass drums and a little less overhang. The initial hit of the bass drum seemed more dynamic. The mids had a little more detail (again different preamp...) but stayed true to the older 802D in the mids. The highs were better. They had more detail and better decay. This all added up to the 802Diamond being a little more transparent and dynamic than the older model.
I have read a number of places the midrange on the 800 diamond is clearer than the 802diamond. I read in a forum somewhere that the 800diamond uses higher quality crossover parts but I don't know if it is true or not. Keep in mind that the 802diamond has a very clear midrange already.