ATC SCM50 ASLT Loudspeaker

Active Alternative

Equipment report
ATC SCM50 ASLT Loudspeaker

The SCM50’s character is underscored by three key properties: One, midrange presence and immediacy; two, midband speed that borders on electrostatic territory; and three, a staggeringly wide dynamic envelope that easily puts electrostats and most cone loudspeakers of this size and spec to shame. In tonal balance, the SCM50 is an exemplar of ease and neutrality across the octaves. This is a no-nonsense speaker, not subject to hyperbole in any frequency range. Its drivers integrate smoothly, speaking with a single authoritative voice, each driver in step with the other. The soft-dome tweeter, especially, deserves kudos for its ease, extension, and openness—a profound improvement over the drier, whiter, third-party tweeters that ATC had to outsource in years past. Transient behavior is smooth rather than underlined and exposed for effect. Bass response plummets effortlessly and aggressively into the mid-thirty-cycle range in my room. Some might opt for more extension but few will be disappointed with the quality that this response represents. Low-frequency musicality is stunning—a combination of pitch control and effortless slam that are hallmarks of ATC’s active products. The SCM50’s woofer has an enviable ability to resolve textures and timbral colors, capably rendering the skins of bass drums, or the flutter of tom-toms, or the dark voicing of orchestral bass viols as bows are dragged across their strings. Where the SCM50 really grabs attention is its talent at holding onto the decay of bass notes. Many speakers are uneven in response or subject to dropouts in the upper-bass and midbass regions. Music reproduction suffers amplitude ups and downs, depending on the pitch of the note and the involvement of the port. Just listen to the acoustic bass in either Harry Connick, Jr.’s cover of the classic “A Nightingale Sang in Berkeley Square” or Dave Brubeck’s “Take Five.” In both instances, the ATC treats each change in pitch with timbral and textural consistency—and does so with an output that doesn’t rise then precipitously fall off. If you really want to hear Paul McCartney’s bravura chops on electric bass guitar listen to “Dear Prudence” aboard the SCM50. The sheer musicality and weight of Paul’s bass playing is fully captured by the level of linearity and midbass dynamics that this speaker produces.

The midrange, with its extended frequency bandwidth, provides the thrills and dynamic thrust that I’ve come to expect from this potent 75mm dome. As I listened to the Manhattan Jazz Quintet playing “Autumn Leaves,” I found images leaping from the speaker like a cat pouncing on a meal. When the trumpet solo kicked in, it was as if the SCM50 had been hiding a can or two of propellant inside its enclosure, just for igniting dynamics.

The SCM50 has an almost eerie immediacy that seems to glean the intent of the musician before his bow touches the string or a note escapes his lips. And piano reproduction is, in a word, breathtaking with an extended range of soundboard weight and resolution that reaches all the way back to the touch of the player’s fingertips.

It would be easy to peg the midrange dome as the only hero of this story, but it’s equally about the inter-driver transfer of the signal—just how well the tweeter and woofer gel playing above and below the midrange. If all the drivers were not equally up to the task, then the transparency of the midrange dome would be unrealized.

Parenthetically, I also had to rethink the issue of dynamic compression on some of my treasured recordings. Turns out it wasn’t always the recording to blame. With the SCM50, keep in touch with your preamp’s volume knob; one of those vinyl albums may shock you with what’s been heretofore hidden in the grooves.

Vocals are fluent, at times almost voluptuous, in their weight and harmonic bloom. Diana Krall’s “I’m Confessing’ That I Love You” is ripe with inflections and a smoky sensuality that wraps itself around your ears. Inner dynamics—the way a singer uses the microphone to capture the intimacy and emotion of a song, moving in towards the mike or farther away to massage micro-dynamics—are equally well expressed. After listening to Mary Travers during PP&M’s “All My Trials,” on an Audio Fidelity SACD, I had to sit back and ponder the eerie reality of what I’d just heard from this fifty-year old minimalist recording. The fly-on-the-wall, “you are there” moments that this track offered were nothing short of a time-machine trip.

The SCM50 thrives, even gathers energy when challenged to reproduce orchestral music. Rather than constrict, lose air, or reduce inner detail as the strings and winds rise in a flurry of complexity, the ATC seems to sail through with aplomb. Similarly, its resolution doesn’t falter as it tracks the sustain and decay of instruments, whether it is a crash cymbal, an organ, or a cello. But what really took my breath away are the layering of images and the width of soundstage reproduction. Less desirous is a lack of vertical soundstaging. The midrange has a specific and direct sound energy. Consistent with its studio roots, the speaker pinpoints images in depth and width. This is a virtue, but there is also a sense of a ceiling over the acoustics of a concert hall that may take an adjustment for some listeners.

In order to discover for myself the sonic distinctions between active and passive, ATC, through its U.S. distributor Lone Mountain Audio, dispatched to me a “conversion kit,” so I could swap out the amp pack/electronic crossover for the standard SCM50 passive crossover, thus creating a near-identical version of ATC’s SCM50 PSLT (P for passive, $21,999). ATC also kindly provided me with its P2 stereo amplifier for the comparo. I managed to make the switch without incident. Minus the tri-amplifying amp pack, this was not truly an apples-to-apples comparo but it was instructive. The differences were obvious. The speaker’s tonal character didn’t change, but its presentation was a tad less self-assured. Images didn’t quite adhere to spatial positioning like they were stuck on flypaper. Soundstaging was just a tad amorphous. The upshot? Still a brilliant speaker, but I’ll take mine with an AC plug, please.

Normally, when I’ve concluded my time with a review product I’m of a somewhat mixed mind, weighing attributes and oddities, balancing the great against the not-so-great. In the matter of the ATC, its exemplary performance over so many criteria pushed any lingering issues into near-insignificance. I think you see where this is going. Yes, I bought these speakers—my review samples being a well-travelled demo pair that had seen life on the road for the better part of two years. They’ve now found a permanent home and will not only be valuable tools going forward, but splendid musical companions in the years to come. Is active for everyone? I’m sure it’s not. But for enthusiasts who are willing to open their minds just a bit, ATC might be the first call you should make.

Specs & Pricing

Driver complement: HF 25mm ATC SH25-76S, mid 75mm ATC Super Dome, LF 243mm Super Linear
Frequency response: 38Hz–25kHz
Power output: 200W LF, 100W mid, 50W HF (active version)
Max SPL: 112dB
Dimensions: 12" x  40.2" x 18.9"
Weight: 117.5 lbs.
Price: $28,999 (satin cherry, oak, walnut, black ash)

Gypsy Lane
Aston Down
Stroud, Gloucestershire
GL6 8HR, England

ATC HIFI USA (U.S. Distributor)
(702) 307-2727

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