Wilson Audio Specialties X-1/Grand SLAMM loudspeaker system Page 7
Several lines of attack were tried to solve these multiple problems. As the X-1 is a single system, its placement has to be simultaneously optimized for both the bass and midrange performance. I had first to find where the low-frequency modes of the room were. This would help me find the optimum placement for both speakers and listeners, the one that gave the most balanced, even, and extended bass performance without sacrificing stereo imaging.
It's undeniable that the Wilson Audio speaker's overall frequency balance is aligned for the best transient definition, with good rhythm and timing. By conventional standards, their bass is often quite dry and well damped (footnote 3). But in contrast to the flexible placement and bass adjustment offered by the Martin-Logan Statements, the room has to serve the X-1, not the other way around. This was a severe lesson. If you want to achieve all the X-1 is capable of, you must have a listening room first, a living room second.
Another factor in this equation concerns the differing radiating patterns of these two speaker systems. The MartinLogan electrostatics' bi-directional nature had given a good forward throw and ample rear-directed ambience. The primarily direct-radiating X-1, even with its rear-facing ambience tweeters, needs to "breathe" in order to properly voice the room and sound suitably spacious. Accordingly, the side rooms and corridors outside the listening room began to fill with displaced furniture—several heavy padded leather easy chairs, coffee tables, and the like. Two magnificent jukeboxes located in a side wing of the room were powered up so that their woofer cones were suitably damped by their internal amplifiers. If you think that's crazy...well, all I can say is that at last the X-1's bass came back!
You just can't afford to give any of the X-1's bass away—nor would you want to! I'd judged the bass to be remarkably good in my room, despite an audible loss in the last half octave down to 18Hz. My measuring microphone confirmed that while the speaker could produce very low frequencies, my room just wouldn't support them. However, Ricardo's room could and did! Aside from a moderate and very narrow dip at 31Hz, the X-1 drove the second room at awe-inspiring levels right down to 18Hz. Using the 20Hz warble tone on the second Stereophile Test CD, it was possible to approach clipping with a Krell KSA-200S (250W continuous) on this track, and hear a body-shaking, earthquake-like thundering free of any untoward limiting or distortion. The dynamic envelope of the X-1 truly extended to 18Hz!
With the increased width of Room 2, the X-1s could be placed between 5' and 7' from the side walls, 50% farther than in my room. However, like my room, Room 2 had a deep bay window behind the speaker position, so the X-1s could be positioned relatively close to the rear wall—about 3' from the back of the bass cabinets. The floor also possesses greater mass than mine, despite the concrete loading I had specified for my suspended floor.
The distance to the listener was just over 15', allowing a close approximation to an equilateral triangle. This resulted in superb soundstage width and focus. Ricardo's ceiling height was also greater than mineק' compared with 9.5'. With this, together with Room 2's increased width, I found that still greater levels of performance were possible from the X-1.
Once again, the specific location of the speakers quickly faded from one's listening consciousness, the X-1 achieving that enviable state of grace: a playback system in which the music counts for more than any deficiencies in the system. Optimally set up, and regardless of the chain of electronics used to drive it (within obvious quality limits), the X-1/Grand SLAMM managed to re-create that satisfying sense of performance, of live music-making, that nearly always transcends the audio components used. I didn't need to know or care how the soundfield was being created in the room—all I had to do was sit back and enjoy it.
In Room 2, not only could the X-1 play louder, with better dynamics and a greater dynamic range; it also sounded even more neutral and natural. Stereo images were best described as extraordinary. Using accurate program, the sense of scale, height, width, and depth was absolutely state-of-the-art. The wholly natural spaciousness was not accompanied by any false phasiness or blurring, while focus was crisp and sharp in all regions of the essentially three-dimensional soundfield.
There were also gains in the bass. I had already admired the speaker's ability in my room to resolve detail and to sound transparent down into the upper bass, a quality wholly comparable with the excellent midrange. But now I could hear this ability extended a further octave, from 80Hz down to 40Hz. Amazingly, this speaker could reproduce individual notes in bass chords. This gave me a shock when I first heard it done right—for example, on cathedral organ and at realistic sound levels. The X-1 exhales clean, clear bass; the room acoustic was held fast and forced to obey the speakers' command. Once again, the percussive bass quality was revelatory both for its precision and its visceral impact.
Room 2's larger space needed and could take more power. Trials at levels up to 300W peak program showed no signs of strain or limiting, although deliberate abuse by their owner with headbanging synthesizer material at up to 500Wpc did pop the fusible resistors to the mid and treble—just as the designer had intended. I'm glad Ricardo carried out this test; I wouldn't have dared!
Footnote 3: The WATT/Puppy 5 appears to be something of an exception, my first trials indicating a quite generous bass.—Martin Colloms