Dynaudio Special Forty loudspeaker

A highlight of my visit to AXPONA, held last April in the Chicago suburb of Schaumburg, was the Dynaudio room, where the two-way, stand-mounted Special Forty loudspeakers ($2999/pair) were being driven by a tubed Octave integrated amplifier. “The stereo image was superb,” I wrote in my show report; “even more impressive [were] the solidity and believability of the softly struck bass drum that punctuates the Ramirez Misa Criola.” I concluded that this dem “illustrated how matching a relatively small speaker to a smallish room can produce optimal and excellent sound quality.”

As its name suggests, the limited-edition Special Forty was launched to celebrate the Danish loudspeaker company’s 40th anniversary. I had already asked for a pair for review before I flew to AXPONA; they arrived just as I was finishing up my review of the Wilson Alexia Series 2 speakers for our July issue.

The Special Forty, the third anniversary-edition loudspeaker from Dynaudio that we’ve reviewed, is both less expensive than and quite different from its predecessors. Dynaudio’s 25th-anniversary Special Twenty-Five ($5200/pair) was previewed by John Marks in his January 2003 The Fifth Element” column, with a very positive Follow-Up review from me in June 2005. While the Special Twenty-Five was a fairly large, stand-mounted, two-way speaker, Dynaudio’s 30th-anniversary model, the Sapphire ($16,500/pair), was an unusual-looking floorstanding design. I reviewed the Sapphire in January 2009, recommended it “with a bullet,” and warned that “the remaining 300 pairs of Sapphires won’t hang around much longer.”

The Sapphire was the last Dynaudio speaker to spend time in my listening room until I wrote about the Contour 20 ($5000–$5750/pair, depending on finish) in our May 2017 issue. The Contour 20 is an elegant-looking, two-way, stand-mounted speaker, and now I’m about to audition another: Dynaudio’s Special Forty.

Special indeed
Actually, when I unpacked the Special Fortys, I was reminded not of the Contour 20 but of Dynaudio’s no-longer-available Focus 110, two of which reside in the office of Stereophile publisher Keith Pray. The Focus 110 used to sell for $1500/pair, and the Special Forty reminded me of it because while a little larger than the ‘110, the ’40 has an enclosure of the same shape, with sidewalls that taper toward the back and a large, flared reflex port on the rear panel. (If the owner finds the bass excessive, foam plugs are supplied to block the ports.)

The differences between the two speakers are substantial. While the Focus 110 used Dynaudio’s Esotec+ D 280 1.1″ soft-dome tweeter, the Special Forty’s ferrofluid-cooled, 1.1″ soft-dome tweeter is the Esotar Forty, a descendant of Dynaudio’s venerable Esotar2, used in both the Special Twenty-Five and the Sapphire. The 28mm fabric dome is treated with what Dynaudio calls its Dynaudio Secret Recipe (DSR) coating, which they say “is applied in exactly the correct places and thicknesses to optimize high-frequency reproduction.” The Esotar Forty’s other improvements aren’t visible, as they involve a chamber behind the tweeter that is filled with damping material; a “pressure conduit” controls the air movement from behind the dome into the chamber. There’s also what Dynaudio calls an “aero-coupled pressure-release outlet” under the voice-coil to minimize resonances, while the neodymium magnet is small and light.

The Special Forty’s 6.7″ woofer is based on Dynaudio’s 17W75 MSP unit, but features an improved spider for better motional symmetry. The cone and its central dome are formed in one piece from Dynaudio’s proprietary magnesium-silicate-polymer (MSP) material, claimed to offer “a precise combination of stiffness, stability, rigidity and damping.” Like the tweeter, the Special Forty’s woofer has a voice-coil wired with aluminum, to keep the moving mass as low as possible. Sitting inside the woofer’s voice-coil is a hybrid magnet system: a powerful neodymium magnet to provide the drive energy, and a ferrite magnet to direct that energy where desired. The benefit is said to be a reduction in second-order harmonic distortion.

As is usual with Dynaudio designs—but unusual for speakers with flat front baffles—the Special Forty’s crossover has first-order slopes. This demands that drivers behave well outside their nominal passbands—Dynaudio says that this was a design priority, that the tweeter’s raw response “extends comfortably down to around 1kHz,” and that the woofer “can easily handle frequencies up to around 4kHz.” The Special Forty’s crossover is set at 2kHz, meaning that there is a “safe zone” of an octave either side of it. The Special Forty’s internal wiring of OFC copper is sourced from van den Hul, and electrical connection is via a single pair of high-quality binding posts below the port.

The Special Forty’s enclosure looks stunning, with unusual striated veneers finished in high gloss. The veneer is created by gluing sheets of birch together, then cross-cutting the layers. Two finishes are available: Grey Birch High Gloss and Red Birch High Gloss. The enclosure’s inner surfaces are also veneered, to increase stiffness and prevent warping.

Setup
I sat the Dynaudio Special Fortys on 24″-tall Celestion stands, which placed their tweeters 35″ above the floor. The stands’ central pillars are filled with a mixture of sand and lead shot, and the speakers were decoupled from the stands with small pads of Blu-Tack. Grilles are provided, but I didn’t use them in my auditioning.

As with all small speakers, setting up the Special Fortys involved placing them close enough to the sidewalls and/or the wall behind them to get respectable low-frequency extension, but without the bass definition becoming obscured by room resonances, or the accuracy and stability of stereo images being degraded by close-spaced reflections.

As my room is somewhat asymmetrical—behind the right-hand speaker, two steps lead to a raised area—I ended up with a slightly asymmetric placement. Both woofers were 98″ from the wall behind the speakers; the right-hand Special Forty was 52″ from the books lining its sidewall, the left-hand one 26″ from the LPs lining its sidewall. I ended up with the ports open, which gave the best bass extension without comprising definition. Looking at the measurements taken at the listening position when I prepared the spatially averaged response (see “Measurements,” figs. 7 and 8), the left and right speakers’ in-room responses were well matched above 500Hz. The differences in the outputs in the region covered by the tweeter was typically <0.5dB.

Listening
The dual-mono pink-noise track from my Editor’s Choice (CD, Stereophile STPH016-2) sounded smooth and evenly balanced, though with some slight emphasis in the upper midrange. If I sat so that my ears were above the tweeter axis, the sound had a slightly hollow quality. The central image of the noise signal was narrow and stable, without any splashing to the sides at some frequencies. As I explain in my 1981 essay on stereo imaging, while dual-mono pink noise is certainly not music and doesn’t present a “soundstage,” it is supremely capable of revealing a pair of speakers’ precision of imaging. As I wrote back then, “For a central listener, one has an absolute yardstick for assessing the quality of stereo imaging, without any reference to musical debate, the ‘real thing,’ direct/reverberant ratios, concert hall acoustics, the subjective experience, emotion quotient, or any other philosophical red herrings. . . . As long as the narrow central image produced by a ‘double-mono’ signal remains narrow and central at all frequencies, then the system must be inherently accurate as far as stereo is concerned.” In their ability to reproduce a stereo image, the Dynaudio Special Fortys are indeed “inherently accurate.”

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Dynaudio A/S

US distributor: Dynaudio North America

1852 Elmdale Avenue

Glenview, IL 60026

(847) 730-3280

www.dynaudio.com

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Specifications
Associated Equipment
Measurements

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