Congratulations Duke on what looks like a great and promising new loudspeaker!
I was scheduled to hear this beauty but last minute issues prevented my audition the day Duke shipped them. For persons who have not had the pleasure of hearing Duke's latest work, he inches closer and closer to the see-through transparency of the world's best electrostatics. I heard the late Bob Crump's CES demo shortly before he passed, with Blowtorch preamp, hot as witches brew Halo JC-1 mono blocks, and huge Sound Lab stats sited 1/3rd the room's length from the front wall. Also auditioned Sanders' big 'stat panels at recent CES. It's amazing to approach that transparency but with a huge sweet spot (stats often have the smallest sweet spot). Also, if you've never heard a speaker that does not thermally limit, you're in for a treat. But be forewarned, the experience will permanently ruin your perception for this level of unrestricted output. It's quite amazing how a speaker's thermal limitations restrict its sound stage size as level increases.
Battery powered fanatics: if battery powered power amps exist, bring them to audition this speaker at the first opportunity.
My setup advice for Duke's Distributed Sub Array changed over the years. My current advice is reasonably easy to replicate in any room within a couple hours, give or take depending if you have help and how fast you work. The FR results speak for themselves. One sub setup in the smoothest location yields a 13 dB FR window at the sweet spot, much worse variation at other locations, and about -6 dB @ 20 Hz. Conversely, four subs, one inverted, yield a 6 dB window, barely worse even in the corners, and -1.5 dB @ 20 Hz. Without EQ and without room treatment.
The 7 dB tighter window is obviously good. But better yet is timing accuracy and the fact there are no hot spots such as result from EQ; bass is generally similar everywhere in the room. Bass systems other than Distributed Array result in severe timing distortion in the bass. The worst and most obvious error is bass notes continue bouncing between walls after the new note appears, resulting in two disharmonious notes. Imagine a double bass section with double the number of instruments called for in the score, and on certain notes half the bass play the wrong notes while the other half play the right notes. This is a good analogy for bass mode effects. Frankly, after becoming accustomed to a complete lack of this phenomena, it is easily noticed and strongly disliked when you hear it later in lesser playback systems.
I remember Bob Carver once told me that humans have extremely high tolerance for HD in the bass, approaching levels in the range of 30% THD. If true, then it is wasteful to spend money only for lower HD in a sub woofer. But this tolerance does not extend to timing, where bass modes cause two disharmonious fundamental tones, potentially spaced by as little as a half-step on the music scale. I don't know the math formula to calculate such distortion, but I feel sure it's exponentially higher than 30%, maybe approaching 300%.
When I worked at VMPS I was convinced low distortion caused the extreme clarity in Brian's huge, floor to ceiling separate bass towers, each with four or six active 12s. I walked up next to the towers and marveled at their pitch clarity and overall presentation, while they effortlessly played St. Saens organ symphony or whatever huge score Brian chose. The active drivers moved little except on large transients. Now I'm convinced their best quality is that such towers damp the worst mode, the floor/ceiling bounce. Plus they are so large that their physical presence in the room minimizes modal effects. They do barely distort, but not for the reasons most people suspect. The fact of their size, weight, and cost are separate issues, all usually negative.
If I only knew about Duke's bass philosophy, and how to implement it prior to spending a lot of money on professional room treatment including three-sided acoustic ceiling soffit, in my last room. You or I or both of us would choke if I disclosed the cost.
From my reading, only Double Bass Array seems competitive performance wise with properly implemented Distributed Bass Array, but the former costs considerably more and is more complex to properly implement.
