Floor Loudspeaker Reviews

One of the joys of reviewing audio reproduction equipment is discovering a little-known product that provides an extraordinary level of performance and musical satisfaction at an affordable price. These components, sometimes made in a garage, reflect the designer's single-minded zeal for musical accuracy, not the sometime corporate mentality of meeting a price point or catering to the latest fad.

Unfortunately, this enthusiasm is tempered by the realization that being a brilliant designer and a shrewd businessman are often mutually exclusive talents. As a result, these components are usually destined to short, sporadic production runs, able to be appreciated by relatively few audiophiles. It is difficult to make the jump from garage operation to full-fledged company with a dealer network.

This brings us to the Vortex Screens made by Vortex Acoustical Engineering of Riverside, California. Designed and built by Albert Von Schweikert (footnote 1) in his proverbial garage, the Vortex Screens epitomize the paradox of a wildly successful design that is unlikely to achieve the commercial success it deserves.

Vortex Acoustical Engineering was founded in 1976 by Mr. Schweikert to develop a speaker that reduced the deficiencies he perceived in existing systems. Four years of research and testing led to the introduction of the original Vortex Screen reviewed here. To date, about 80 pairs of the original Screens have been sold, most of them directly through Mr. Schweikert. In 1988, Vortex introduced a new $3000 model, also (confusingly) called the Vortex Screen, that improved on the first design. All references to the Vortex Screen in the review are to the original Vortex Screen (no longer produced).

The Screen is a large, floor-standing speaker using conventional, well-known dynamic drivers in a somewhat unconventional enclosure with decidedly unconventional crossovers. Standing 48" tall, 24" wide, and 9" deep (excluding the base), the Screen's proportions are reminiscent of the monolith in 2001: A Space Odyssey. This impression is further reinforced by the fact that the Screen is completely covered by fabric bags, obscuring any hint of the design or driver complement. The Screens are available in black or an unusual off-white/beige color called "Desert Sand." The Screens are quite attractive, especially in the desert sand color that I chose for my listening room. This lighter color helps the Screens blend into their environment, making their large size less imposing in small rooms. The base extends 4" in front and 4" behind the speaker, and is finished in either black or off-white Formica to match the bags.

Design
Removing the fabric bag by unscrewing the base from the enclosure reveals the Screen's salient features. A 9" Dynaudio plastic-diaphragm woofer is mounted in a transmission-line enclosure that occupies the majority of the particle-board cabinet. The end of the folded labyrinth couples to the outside air at the side of the enclosure.

A 5" Audax midrange and a 1" Audax soft-dome tweeter are mounted in the "open air" top section of the cabinet. No exotic drivers here. The uppermost 13" of the cabinet is merely a frame to support the fabric bag. Both midrange and tweeter are set back slightly to physically time-align them with the woofer. This open-air design reduces diffraction from the cabinet. In addition, all cabinet edges are rounded to further reduce high-frequency diffraction. A panel mounted on the back of the speaker holds a five-way binding post and three fuses, one for each driver.

So far, the Screens don't appear that much different from some other three-way dynamic speakers. Indeed, with the fabric bags removed, they look somewhat like oversized Vandersteen 2Cs. The crossovers, however, hold the real surprises. Mounted on the bottom of the enclosure, the Screens' crossovers are among the most complex and expensive-looking I have seen. The 22-element design utilizes high-quality polypropylene capacitors and air-core inductors in fourth-order (24dB/octave) slopes at frequencies of 150Hz (!) and 3kHz.

According to the designer, the choice of such a low crossover frequency between the woofer and midrange is critical to the Screens' freedom from coloration in the all-important midband where the ear is acutely sensitive to tonal imbalances. In addition, problems associated with crossover points are shifted into a frequency range of significantly less auditory acuity. A primary design philosophy behind the Screens is that accurate midrange reproduction is a prerequisite for successful speaker design. According to the literature, the crossovers also employ three servo loops (?) to correct phase, impedance, and hysteresis variations.

I had some concern about driver overload distortion and the potential of driver failure when crossing over a 5" midrange at 150Hz, despite the steep slope of the fourth-order filter. Although the Screens played very loud without a hint of audible driver stress, I did, however, experience a midrange failure (a buzz from a loose voice-coil) after about five years of operation. The driver was replaced under warranty (even though it was a few months past the five-year warranty period) and has since performed flawlessly. I don't know if this failure was a confirmation of my concerns or a random event. Given the Screens' overall exceptional design, it is unlikely that the designer would have compromised the system by such an obvious flaw, if indeed it is a flaw.

The System
The Screens have been in my hi-fi system for over six years and have been driven by a variety of equipment. The system used for this review consisted of a Luxman CL-34 tube preamp, Adcom GFA-555 power amplifier, an AR turntable with an Ortofon MC-200 moving-coil cartridge with its associated step-up transformer, and a Sony CDP-520 ES CD player. Interconnects were Monster Interlink II and speaker cable was Monster Powerline II.

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Footnote 1: In 1996 Albert Von Schweikert founded Von Schweikert Audio, which in 2020 is run by Leif Swanson and Albert's son Damon.—Ed.