Deep in the Gloucestershire countryside, nestled in a pretty country lane between wild hedgerows, lies the headquarters of perhaps the world’s most respected manufacturer of professional loudspeakers. Since 1974, ATC—the Acoustic Transducer Company—has designed, engineered, and built professional monitor systems for a client list that seemingly includes most of the leading recording or mastering studios on Earth. ATC speakers hang in the Sydney Opera House, the Royal Festival Hall, and Ronnie Scott’s Jazz Club. ATC speakers were used by Doug Sax at The Mastering Lab while he was cutting many of his vinyl masterpieces. The company’s client list reads like an A–Z of the world’s most beloved artists, including Enya, Kate Bush, Bruce Springsteen, Mark Knopfler, and Pink Floyd. In short, if you want to hear Pink Floyd the way that David Gilmour does, you’d better use ATC speakers.

The firm’s factory is housed in a couple of mysterious-looking former Royal Air Force buildings. When I visited last summer, it felt like I had stumbled upon the secret world of a kitsch 1960s spy thriller. I half-expected a purple-catsuited Diana Rigg to emerge from a side door and drive away in a pale-blue Lotus Elan. In the event, there was no sign of Rigg, but I did learn that I had narrowly missed singer-songwriter Chris Rea collecting a pair of his loudspeakers that had just been repaired.


When former Goodmans engineer Billy Woodman founded ATC in 1974, there was a very healthy British loudspeaker industry that built systems with high neutrality but limited dynamic range. By contrast, there were many speaker systems being produced in the United States capable of high dynamic range—but they also had high tonal coloration. ATC was born of a desire to engineer speaker systems combining the virtues of high neutrality and extended dynamic range. Initially, the company focused on supplying monitor systems for professional studios, broadcasters, and concert halls; more recently, ATC has produced an increasingly successful range of loudspeakers for the home.

A key element which distinguishes ATC from the majority of loudspeaker firms is that it designs, engineers, and builds all of its drive units entirely in-house. While most other manufacturers source drive units from third-party firms and bolt them into cabinets, ATC starts with a blank sheet of paper and designs everything from the ground up to perform precisely to its requirements. And not just the drive units—the firm also manufactures the voice coils, crossovers, active amplifier packs, and even some of the cabinets. This guarantees that every component that goes into a unit is manufactured to ATC’s exacting tolerances, and provides the company with absolute control over the resulting sonic performance. Such commitment to in-house engineering excellence reminds me very much of SME, another legendary British marque with fastidious attention to detail bordering on obsession.

Aside from hearing the company’s speakers at industry shows, my first proper encounter with ATC was in 2005, when I reviewed a pair of its SCM20-2 standmounts for Hi-Fi News & Record Review magazine. Those speakers were a revelation and left a very deep impression, so I jumped at the opportunity to review a pair of ATC’s SCM40 passive floorstanding loudspeakers ($7999 per pair, all prices in USD) for SoundStage! Ultra.


The SCM40 resides at the top of ATC’s Entry Series hi-fi loudspeaker range and is a three-way floorstanding design of modest proportions: 39.6″H × 14.6″W × 12″D, including plinth and spikes. These are no lightweights; each unit weighs a hefty 68 pounds, and the pair certainly provided a workout as I finalized their positioning. The fully sealed, infinite-baffle MDF cabinet is extensively braced and impressively inert to a knuckle rap. The gently curving sidewalls are designed to reduce internal reflections, and the front baffle is wider than the rear of the cabinet. During installation, the cabinet is bolted to an MDF plinth, which accepts adjustable spikes. Four cabinet finishes are available to suit a wide range of decor: Satin White, Satin Black, Cherry, or Black Ash. A protective metal grille attaches to the cabinet via hidden magnets—a nice touch, that. To the rear is a set of sturdy 4mm binding posts with facility for triwiring.

Below the SCM40, the Entry Series comprises the SCM7 bookshelf, the SCM11 standmount, and the SCM19, which comes in passive standmount and active floorstanding variants. The SCM40 is also available as an active floorstanding system, but I elected to review the passive version. Above the SCM40 lies the Classic Series, whose SCM50, SCM100, and SCM150 models are closely related to their counterparts among ATC’s professional studio monitors.

The current version of the SCM40 was launched in 2014, featuring the new, curved cabinet design and an all-new 1″ soft-dome tweeter—the SH25-76 model—that, according to ATC, offers significantly improved performance. This enhanced performance arises from some revolutionary design approaches; for example, the tweeter has a unique dual-suspension design, which reduces rocking modes and negates the need for ferrofluid. Often used in drivers for cooling and damping, ferrofluid tends to thicken with time. This results in a gradual degradation in performance, so its elimination is highly desirable. The design also enables the magnetic gap to be made smaller, allowing ATC tweeters to offer increased power handling over conventional designs. The crossover point is at 3.5kHz.


The SCM40 uses ATC’s legendary SM75-150 3″ soft-dome midrange, regarded by some as the best midrange drive unit ever made. The dome is a hand-doped acrylic diaphragm on a dual-suspension system, with a highly linear drive system designed to deliver uniform dispersion, wide bandwidth, and low distortion. It is worth noting that this is a slightly different variant of the midrange fitted in ATC’s huge SCM150 and SCM300 studio monitors, with reduced efficiency. This seems entirely reasonable when you consider that the SCM40 is unlikely to be playing back a 24-track mix of the latest Springsteen album at 125dB for 18 hours a day like its professional siblings. The SCM40 is the cheapest entry point to the magic of that legendary midrange, and I was keen to see what it could do.

The 6.5″ long-throw woofer crosses over at 380Hz, and is yet another in-house design—with a hand-coated carbon-paper diaphragm driven by a short coil in a long gap, and a highly over-specified heavy voice coil and magnet system. The design maintains linear coil forces and inductance to ensure low distortion even at high sound pressure levels.

System and setting up

Listening commenced in my 33′ × 14′ room with the speakers placed to fire across the short axis of the room, around 9′ apart, 12″ from the front wall, and slightly toed in. ATC claims that the SCM40 presents a benign load to amplifiers; nominally 8 ohms, with a broadly flat impedance curve. However, the sensitivity is low by modern standards at 85dB (1W/m). As a result, the firm recommends amplifiers in the 75–300Wpc range. My review system comprised Naim’s NAC 82 preamplifier, NAP 250 power amplifier (80Wpc into 8 ohms), and HiCap power supply. Sources included my Michell Engineering GyroDec Mk IV turntable with SME Series IV tonearm and Audio-Technica AT-OC9ML/II moving-coil cartridge. The vinyl front end was fed into a Trichord Research Dino Mk 3 phono stage with Trichord Never Connected Dino+ DC power supply. Digital sources included my Naim CDI CD player and Naim NDX streamer, with source material either from Tidal or my own local FLAC music library.



To gain an initial impression of the ATCs, I opened proceedings with “Miss You,” from the Rolling Stones’ Forty Licks compilation album (CD, ABKCO Records CDVD2964). This isn’t an audiophile recording by any means, but through the ATCs it sounded like I had just walked into a dive bar and the Stones were jamming and grooving on the stage! Charlie Watts’s drums sounded astonishingly live and visceral, with realistic weight and scale, but even more jaw-dropping was the speed of attack of his snare—it was as percussive as a machine-gun burst. The drumming on that track is a wonderful example of how Watts accented his playing to emphasize certain drum hits and in 35 years of listening to audio systems, I had never heard this more clearly revealed on any system at any price. Think about the last time you stood next to someone playing a drum kit live: how clean, tight, fast, and physical it seemed and then reflect on how very different drums sound on 99% of the world’s hi-fi systems. Some of this is dynamics, some is speed, and the rest is bandwidth. The combination of my Naim amplification—which majors on timing and speed, and has the ability to swing huge currents instantaneously—with these superbly engineered ATC monitors was mesmerizing.

Thankfully, this pair of SCM40s was no one-trick pony; that glorious midrange driver made sure that every nuance of Jagger’s pouting delivery was reproduced with palpable presence and outstanding clarity. Mel Collins’s brief saxophone interjections had superb ripeness and clarity, and Bill Wyman’s wonderful, strutting bassline was gorgeously rich and fruity. On so many loudspeakers there is a sense of “one note” bass—just a tuneless rumble—that kills a track like this stone dead, because the melody line on the bass is so vital to the swing of the song. There was none of that here; every single bass note was pitch perfect and perfectly delineated. Overall, this was a tour-de-force rendition of a much-loved classic.


Keen to evaluate how the ATCs would render female vocals, I picked a personal favorite: The Corrs’ masterful Unplugged set (CD, Atlantic Records 7567-80986-2) and the track “No Frontiers.” This live performance by the band, recorded just before they rose to fame, is an essential purchase for anyone who loves melodic female vocal rock. The honesty of this recording was fully conveyed by the SCM40s and the awesome purity, yet distinctive character, of each of these three astonishing female singers was laid bare. At no point was I aware of the crossovers between drivers, and the sound was impressively cohesive. This is a very good recording indeed, but the ATCs excavated a forensic level of detail from the disc. This wasn’t mere playback; once again, it felt like live performance, and the three singers were palpably ranged across the stage in front of my listening seat with pinpoint precision and lifelike scale. The feeling of being in a sizable acoustic space or a small auditorium was utterly convincing. The SCM40s painted the soundstage with architectural precision—I could tell exactly how big the room was and precisely where each performer was located. The illusion was so convincing that my hands instinctively went to clap as the song drew to a close!

One of the things that concerned me most about the SCM40 was the relatively small size of the bass driver, at a mere 6.5″ in diameter. I suspected at the outset that the dimensions of my 460-square-foot listening room might require a driver with a larger cone area to provide full-bandwidth sound. ATC quotes the frequency response as 48Hz–22kHz at -6dB, and it’s worth remembering that even a piano extends down to 27.5Hz on its lowest note. And yet, I was surprised to find myself pulling these speakers farther out into the room because there was too much bass! Aston Martin, with typical British stiff upper lip, once described the performance of its Vantage V8 as “adequate,” and I’m inclined to believe ATC has a similar wry tendency to understatement.


While the SCM40s were in for review and I was singing their praises, a good friend who is a drummer and keen music lover came around to listen. He spent the first ten minutes utterly convinced I had hidden a subwoofer somewhere in the room, or had secretly wired in one of my home-theater REL Acoustics subwoofers for music replay. I hadn’t, of course; the ATCs were quite capable of pressure-driving the room themselves on some tracks. Nowhere was this more apparent than on “Weather Storm,” from Claude Challe’s stunning first Buddha-Bar compilation (CD, Mercury Records 546 363-2). The bass synths and electronic drums on this track reached deep into subsonic territory to the point where you could feel the block walls of my room shuddering and the air in the room jolting. This was bass at a pitch where you felt it as much as heard it. I’ve heard very few loudspeakers capable of going this low with such a sense of unbridled power and control and none at this price, or even close to it. The low sensitivity undoubtedly helps extend the bandwidth of this speaker and for sure it likes to be fed power in spades. Don’t expect to connect them to a nice 40Wpc integrated amp and achieve good results. My NAP 250 at 80Wpc is the bare minimum I would use, but then again I sometimes like to listen at levels that approach those of a live performance.

While we are on the subject of listening levels, the SCM40s are loudspeakers that really respond to volume. They performed well at low listening levels (and I’m thinking hotel-lobby Muzak levels here), but the sound really opened up as the volume rose. You don’t need to put yourself in the mosh pit at a Clash concert, but when listening to Kate Bush’s stunning debut album, The Kick Inside (CD, EMI Records EMC 3223), and the track of the same name, I found that a volume approximating the level of a live piano in the room achieved the best results. This is a gorgeously intimate and haunting recording, which has virtually no instrumentation apart from Bush’s voice and her piano. The ATCs projected her soaring teenage vocals deep into the room with extraordinary levels of expression and sensuality. There was a feeling of boundless dynamic range and a vividly lifelike quality to her voice that sent shivers up my spine. There’s a line in this song where Bush sings “I’m giving it all, giving it, giving it, giving it,” at which point she strikes the next piano chord with dramatic ferocity. On lesser systems, this searing intensity isn’t fully realized—there’s compression and a lack of attack to the notes—but with the ATCs I found myself pinned to the seat, near rigid with emotion. It’s moments like this that make all the years of saving and sacrifice, all the faffing about with cables and worrying about dedicated AC wiring, utterly worthwhile. In these musical moments it all makes perfect sense; and you realize, while sitting in your favorite chair and listening to Kate Bush pouring her heart out to you so intimately, that your eyes are full of tears.


Spinning up the hypnotic GyroDec, I slipped on a favorite classical recording—The Academy of Ancient Music, under Christopher Hogwood, performing Vivaldi: The Four Seasons (LP, L’Oiseau-Lyre 410 126-1). From the very first note, the SCM40s captured every single nuance of wiry horsehair bow on gut string with astonishing transparency. The ensemble was precisely located within the marvelous acoustic of London’s Kingsway Hall, and as each soloist stepped into the limelight I could sense their location with great precision. Once again, I had the sense of witnessing a live performance. During the busy opening movement of “Summer,” the period violins and violas danced, swooped, and soared with a feeling of unlimited headroom and bandwidth. The resulting sound was vivacious and utterly captivating—but never shrill—and proved that the ATCs are emotional communicators of the first order. They revealed every detail of the performance but never in a way that deconstructed its majesty. The Academy was clearly presented on the soundstage as an ensemble, but I could easily follow a particular instrument if I chose; its phrasing, color, timbre, and expression were laid naked before me. These loudspeakers were so impressive that they kept me up well into the early hours, delving deep into the dark recesses of my vinyl collection and to hell with the clock!


The ATC SCM40 is an extraordinary loudspeaker at this price and it’s very hard for me to think of anything that comes close, even at twice its cost. There are speakers that reveal more at very low listening levels—my own Naim SBLs, for example—but the SCM40s opened up and took a clear lead once the volume rose a little. The ATCs are beautifully built, easy to accommodate, possess world-class dynamics, deliver a powerful full-bandwidth sound, and are blessed with what I think is the world’s best midrange driver. Fed by good sources and driven with enough power, they delivered superb transparency and soundstaging. With their refined new tweeter they are more tolerant of poor recordings than many loudspeakers at this level. The SCM40s had astonishing timing and speed—there was zero overhang, and transient sounds were delivered like a bullet through a plate-glass window. They could groove and rock with the best, yet displayed superb delicacy on classical instruments or solo piano.

As I revealed at the start of this article, I reviewed a pair of ATC speakers 16 years ago and nothing I have heard in the intervening years ever came close to their sound at their price point. Sadly, I returned those original speakers due to fiscal constraints and spent the following decade-and-a-half regretting the decision. In lover’s terms, that pair of speakers was “the one that got away.” Well, not this time, baby. Slip another album on the GyroDec and pour a drink, it’s gonna be a long night.

I finally bought them . . . .

. . . Jonathan Gorse

Associated Equipment

  • Analog sources: Michell Engineering GyroDec Mk IV turntable, SME Series IV tonearm, Audio-Technica AT-OC9ML/II cartridge, Trichord Research Dino Mk 3 phono stage with Never Connected Dino+ power supply.
  • Digital sources: Naim CDI CD player, Naim NDX streamer.
  • Streaming sources: Tidal HiFi, library of ripped and downloaded FLAC files (up to 24/192) on dedicated Netgear ReadyNAS 2×2TB server with X-RAID.
  • Preamplifier: Naim NAC 82.
  • Power amplifier: Naim NAP 250.
  • Power supply: Naim HiCap.
  • Cabling: Naim interconnects on all Naim digital sources, Chord Company interconnects for phono stage and other primary sources, QED interconnects for secondary sources, Naim NAC A5 speaker cable, Grahams Hydra Power Cable for Naim Systems.

ATC SCM40 Loudspeakers
Price: $7999 per pair.
Warranty: Two years, extended to six years on product registration.

US distributor:
Lone Mountain Audio
7340 Smoke Ranch Rd,
Las Vegas, NV 89128
Phone: (702) 307-2727


Loudspeaker Technology (ATC) Ltd.
Gypsy Lane
Stroud GL6 8HR
United Kingdom
Phone: +44 (0)1285 760561
Fax: +44 (0)1285 760683