Wilson Audio Specialties X-1/Grand SLAMM loudspeaker system Page 8

Sound in a nutshell
The following is condensation of all the results from the many listening tests undertaken in both locations.

The most exciting aspect of the X-1/Grand SLAMM was undeniably its extraordinary dynamic expression. Really good dynamics do not result from any single aspect of technical design. Rather, a whole group of interrelated factors come together to generate accurate, lifelike dynamics. These include low distortion, high thermal capacity, low coloration, and fast attack and decay of transients. High sensitivity and good electrical load matching are also important here so as not to compromise the signal from the power amplifier. If the amplifier cannot deliver good dynamics into a specific speaker loading, there is no way that the speaker can be made to reproduce them.

Compared to the X-1, other speakers sounded rather polite, dulled, quiet, and compressed. It was as if the X-1 took a high-contrast photo with very fine gradation—like an Ansel Adams study of Yosemite in winter.

Subtle low-level information was accorded its own "microdynamics," this just as exciting in its way as were full orchestral crescendos. I remember with amazement the way the X-1 could pick out a harp within an orchestra and find full expression in the way it was played.

Its dynamic range was huge. Remaining very transparent at literally milliwatt levels, around 60dB peak, it could still deliver a terrific undistorted impact above 115dB. Moreover, clean audio power was available right down to 20Hz.

With that amazing transient definition and clean attack came a remarkably fine presentation of rhythm and timing. Its sound was firmly upbeat, and involving. It communicated a sense of lively performance on classical, jazz, and rock program.

Coloration was low, what little there was often tending to be associated with sources and speaker location. That's not to say that the X-1 has no coloration at all, but that these other factors were relatively more influential. I might point to a touch of lift in the upper bass as well as a touch of upper-midrange "leanness" and "forwardness" which could result in a trace of hardness. There was also just a hint of "plastic-cone" character detectable on piano recordings in a small region above middle C. The treble may not have been perfectly sweet, but neither the transparency nor the detail were affected one iota; by established standards, the X-1's treble is very, very good.

This speaker was characterized by such a high degree of definition throughout the frequency range that it was not worth splitting up the discussion of this area of performance into bass, mid, and treble ranges. Excellent detail was present throughout. The frequency response was essentially uniform and well balanced, with a very wide bandwidth encompassing the entire audible range. No excess or boom was evident at low frequencies.

Stereo focus was truly exceptional; the very good focus in my room was easily surpassed in the larger space of Room 2. Here the X-1 focused sharply everywhere in the soundstage, and was also rather less critical of listener position. Soundstage width and depth were both excellent, while there was a most natural impression of height. Very convincing perspectives were established, extending from a little in front of the speaker position to far beyond the back wall of the room.

The Wilson Audio X-1/Grand SLAMM sets entirely new standards for loudspeaker performance and sound quality, and I cannot be confident that I've yet found its measure. I feel sure that it won't age for many years to come, but will continue to sound better with future improvements in ancillary equipment.

Realistically loud, full-range piano and orchestral reproduction is possible with this speaker. Typically it will play 10dB louder than the competition—a doubling of subjective loudness.

As for the sound, it's out of this world. Time and again this speaker tested my ability to assess just how good it really was. Invariably, it measured the quality of the source and the subsequent audio chain. Ruthless in exposing faults in room acoustics, placement, and system, it wasn't unkind, but set such high standards that its use was exacting. Even when performing in an averagely good setup, the X-1 worked well; but it really sings when optimally set up.

Wilson's X-1 puts the excitement and pleasure back into reproduced audio. This unique Class A, full-range reference loudspeaker system carries my admiration and heartfelt approval. Truly great products like this are rare indeed.

Wilson Audio Specialties
2233 Mountain Vista Lane
Provo, UT 84606
(801) 377-2233