Beolab 90 is one of those DSP powered speakers aiming at minimizing room influence, alongside Dutch&Dutch 8c and Bruno Putzeys' Kii Three which I cited earlier.
Yes, there's plenty on here on Beolab's but regardless of those in this presentation Geoff Martin I think provides a good explanation about very sound stage and imaging different speakers provide, as an observation of OP. They just use DSP and many drivers to mimic these (many different speakers) all in one. If we disregard Beolab 90's and just think of different speaker characteristics, we can see the difference of speaker-room interaction.
I think that most of us love big sound stage and precise imaging and depth all together, because it is required if we want to "declutter" and unfold the mixed cues and perceive them as layered, focused and orderly for critical listening. These are different things, and may be a lot to ask of just one pair of speakers, at least for far field listening. I am glad that there is so much research and finally modern ways to find "good ones", objectively measure and predict their in room response (read ASR
). I wish I had access to any, let alone modern equipment when I designed mine.
So, it turns out that if we want correct and focused imaging (true to the recording), we need better, more uniform directivity across the frequency spectrum. The more frequency dependent directivity is (i.e if we let lower frequencies be wider and higher frequencies narrower), the less focus we get. As given example, vocal occupies more places at the same time, which in return confuses the brain by blurring the perception. Further more, lower, i.e wider ranges of frequency reflect of the wall and give away where the speakers are located. Even more confusion. How can a listener compute directional cues if they are telling contradictory things? Not going to happen.
When we are engaged in near field listening, we just point any speakers on axis, et voila! But far field is apparently a different story. I think a lot is explained in the video if we look carefully.