I have been pondering the same question for a while and do think it is possible with the right monitors (untested hypothesis). Kalman Rubinson of Stereophile, in his review of the Kii Audio Three hinted at the answer: “If I use Dirac Live equalization to correct my room's sound, my current reference speakers, the Bowers & Wilkins Diamond 802 D3s, don't sound much different from the Kii Threes….” The Kii’s are $12k (and he was not using Subs) compared to his $22k B&Ws. The Kii’s use inexpensive drivers according to diyAudio (Peerless $20 x 4, Dayton $16 and Seas $74) but do rely on sophisticated DSP techniques. I would be very curious if one uses a less expensive well-engineered monitor with “good quality drivers, a solid cabinet, low distortion, good off-axis response” such as the $4k Revel M126Be or $4k Ryan S610, (both that can get to ~50 Hz) and add subs and DSP, the sound can actually get there. Anyone in my area with Revel’s want to conduct a fun experiment?
Do $2k speakers + DSP = $50k speakers?
Now that I have your attention, I’d like to share one of my recent experiments. Like many of you, I've never truly been satisfied with my system and often consider purchasing higher-end speakers. I have a variety of speakers in my house including small, high-quality monitors, and mid/high level floor standers and a few subs (all names left intentionally blank) from $2k to $15k. One part of me enjoys the flexibility of monitors while the other part prefers the full-range sound of floor standers. I have a mid-sized room with some strategically placed panels, but the room is average at best.
As a fun project, I used Dirac room correction and bass management, via a MiniDSP unit, to tweak the frequency response of my floor standers. I then used Room EQ Wizard to further tune the frequency response and properly integrate my subs. They sound “good” (and far better than they did without the EQ), but I suspect they’re ultimately limited by the room. I then used this result as a baseline to see how far I could go with my monitors (1/10 the price of the floor standers). I set up my monitors in nearly the same position and went through the same process. I worked to bring the response as close as I could to the floor-stander baseline as possible. I did not fully invest the time to seamlessly integrate the subs, but I must admit I was pretty shocked as to how close I got things when I A-B'ed them.
There are so many speaker manufactures out there with unique strengths and focuses. If you select a speaker with good quality drivers, a solid cabinet, low distortion, good off-axis response, and solid engineering behind it, is the only hurdle left frequency response differences? Can a $2k speaker (with subs and DSP) = a $50k speaker? Thoughts?