ATC SCM19 Loudspeaker

Where The Drivers Do The Talking

Equipment report
ATC SCM19 Loudspeaker

For the past forty years, British loudspeaker-maker ATC has forged an enviable reputation in recording/mastering studios, concert halls, and post-production facilities worldwide. Its professional active monitors are akin to precision tools, as faithful to the source as they are indestructible. Though not as well known in the high end, the same bloodline holds true in ATC’s consumer line of mostly passive loudspeakers. The company’s across-the-board excellence has never been more evident than in its latest offering, the SCM19.

The SCM19 is the largest of three two-way compacts that make up ATC’s new HiFi Series. All passive, acoustic-suspension designs, and affordable (by ATC standards), the line also includes the SCM7 and SCM11. The cabinets are conservatively tailored yet elegant—ATC has never been prone to flights of whimsy in its enclosures. Viewed head-on there is no extraneous hardware; even the unique metal grilles attach via hidden magnets. Notable are the curvilinear side panels that arch toward the back panel, a design known to reduce internal standing waves.

The look and selection of materials remains traditional, even Old School some might say—MDF enclosures, doped-fabric mid/bass diaphragms rather than the latest exotic craze in cone materials. If anything, this is entirely consistent with the stated philosophy of ATC’s founder and chief designer Billy Woodman, who said in a TAS interview [Issue 117]: “It is our aim to produce loudspeakers of a neutral fidelity, with no particular signature, and capable of wide dynamic range when driven by a suitable amplifier. We try to produce the best loudspeakers in the world, not by breaking new ground, but by the application of better engineering to established principles.”

Actually, it’s more accurate to characterize ATC as, first and foremost, a transducer company. Other loudspeaker manufacturers typically source their drivers from third parties; ATC doesn’t. Its transducers are still engineered, tested, and assembled as they have been for decades in the same, small facility in Stroud, England. And they remain exclusive to ATC. Don’t bother looking for ATC drivers on other consumer brands; you won’t find them.

There was, however, one exception to ATC’s house-designed rule—tweeters. For years they were sourced from SEAS to ATC’s specifications. No longer. Following some lengthy R&D ATC began producing its own soft-dome tweeters. The tweeter, designated model SH25-76, represents a jewel in the crown of ATC transducer design. This 25mm soft dome is a short-coil, long-gap, dual-suspension design, like ATC’s famous 3" soft-dome midrange. According to ATC, the configuration “ensures pistonic motion and suppresses rocking modes even at high output levels.” ATC reports that its diaphragm “is based on a complex geometry which maximizes power transfer from the former, extending the high-frequency response and giving a smooth off-axis response.” The design also enables the use of a narrow magnetic gap and negates the requirement for ferrofluid—and the potential negative effect of the fluid drying out over time. The tweeter is set in a resonance-free, machined-alloy waveguide that’s been calculated for optimum dispersion and the flattest possible on-axis frequency response. Later this year a high-efficiency “S” version of this tweeter will debut on pro and select consumer models.

Midrange and bass frequencies are handled by ATC’s top-rung 6.5" Super Linear mid/bass unit—a driver with a sophisticated diaphragm structure that integrates the dual profiles of a traditional cone with a 75mm soft dome. Per ATC tradition, it features a short coil in a long gap, a massive ceramic magnet, and long-throw suspension for linearity at extreme dynamic levels. The ultra-rigid basket construction is so sturdy it appears ready to launch into space. Given the output levels that are expected of these pro transducers, space-launch is not far from the truth. At 85dB sensitivity, however, power is what the 19s require. They gobble it up like candy, and won’t be in full song at less than moderate volume levels.

I’ve owned ATCs for years, a relationship that began with the classic SCM20SL, later the SCM20-2—both direct descendants of ATC’s active studio monitor. The SCM20s invariably shared one thing with their pro-monitor progenitors: They never communicated in a passive voice. The ATC sound is fully committed, never retiring. And so it goes with the new SCM19. Its resolution is unstoppable, as if it is on a mission to exploit every single aspect of an amplifier’s output. Tonally faithful to the source, the 19 is brimming with midrange power and a single-driver like coherence, challenging if not surpassing its compact predecessors.