Our Verdict 
The ATC SCM40As are the most affordable way to get a full dose of ATC’s technology and engineering. The results are terrific
Terrific detail resolution
Exceptional dynamics and control
Composure at high volume levels
Convincing tonality
Seamless integration
Performance loses sparkle at low volume levels
Reviewed on

Two things strike us when we first unpack the ATC SCM40A floorstanding loudspeakers. The first is the sheer weight of the things. They pile in at 36kg each, meaning a strong, helpful friend is handy come unpacking time. It will help avoid damage both to the speakers and your back.

And then, once we wrestle them out of their boxes, it occurs to us these may well be the best-value speakers ATC makes.

If the idea of a six grand floorstander being called good value bothers you, consider that there’s no cheaper way of getting a full dose of ATC’s heavy-duty engineering and studio-proven technology than the SCM40As.

Drive units

ATC produces its own bass and midrange drivers, but the new tweeter is a first. It's an impressive unit

What makes ATCs different from their rivals? It comes down to drive units, mostly. There are few speaker companies outside of the industry giants such as B&W and Focal that make their own drive units. Most small manufacturers – ATC is tiny by most standards – buy in units from OEM suppliers such as Scan-speak or SEAS.

Usually such drive units are bought off the shelf, but occasionally they will get modified slightly if the quantities are large enough. With the introduction of an in-house designed and manufactured tweeter, ATC is a rarity among small speaker companies in that it now makes all its drivers. It’s taken the company years to accomplish this feat but now it has total control over the design and quality of its drive units.

The SCM40A features a new 25mm tweeter and is also home to the company’s trademark 75mm soft-dome midrange (introduced way back in 1976) and 16.5cm bass driver.

We’ve been to visit the factory and seen these units being made. It really is a labour intensive process with most operations done by hand. However, the result is that these heavily engineered drivers are as rugged as they come and deliver sonically to a terrific degree.

Build and design

ATC is also a strong believer in active operation where power amplifiers are connected directly to the drive units fed by a crossover that works at line level. The advantages of this approach are more accurate handling of the crossover points and the improvement in control given by the direct connection between the power amplifier and drive unit.

The company certainly makes passive speakers, such as the Award-winning SCM11, but talk to any of the engineers and it’s very clear that they consider the active approach superior.

The SCM40A has three power amplifiers (and an active crossover) in each enclosure: there’s a 150 watts module for the bass driver, 60W driving the midrange and a 25W amplifier just for the tweeter.

More after the break

It all comes wrapped in a solidly made, curved cabinet. The cabinet is available in two finishes; the cherry of our review sample and a black ash. Considering the functional-looking products the company has traditionally turned out the SCM40A are smart, and should fit in well in most medium to large rooms.

Our only concern on the aesthetics side of things has to do with the supplied metal grilles; they’re not particular classy. Connectivity is limited to a balanced XLR input and the need for mains power.

Just add an appropriate preamp – we used our reference Bryston BP26 or a suitably talented source with a variable output.


Once up and running, these are deeply impressive speakers. While magnificently detailed, they sound notably less clinical than some ATC actives we’ve heard in the past. That doesn’t make them any less insightful, and that’s a great thing.

We listen to a range of recordings from Keith Jarrett’s Paris/London: Testament and Tchaikovsky’s Swan Lake all the way to Dead Weather’s 60 Feet Tall and these speakers take it all in their stride, showing no bias towards any particular genre. That points to speakers that have a broad range of strengths, and get all the fundamentals of sound spot on.

The way these floorstanders reproduce dynamics is excellent. They have the reach to convince with the large-scale dynamic swings of Swan Lake, punching out crescendos with enthusiasm. There’s an impressive dose of muscle here, and the kind of low-end authority that only really capable big speakers truly manage.

Yet these ATCs are more than happy to turn their hand to subtlety when required. Jarrett’s piano playing simply sparkles with the SCM40s rendering the shape and harmonics of each note beautifully. Not only that, these towers link the notes superbly, producing a fluid sound that also stops and starts brilliantly.

If you want to analyse a recording we can think of few alternatives as good. Every subtlety is sharply defined with the speakers keeping organised and controlled even when the music becomes complex. Most Hi-fi – even true high-end kit – has problems making sense of Radiohead’s 15 Step.

Not these ATCs. They take all in their stride, making sense of the plethora of sounds and noises, arranging it all to make perfect musical sense.

This kind of performance happens only when resolution, timing and dynamics are spot-on. Their tonality is resolutely neutral. At low volumes there can be a loss of sparkle, but once the volume turns to medium levels and higher these SCM40As sound right at home.

They have a lovely cohesion throughout the frequency range, with a consistent sonic character from the lowest notes upwards. Such tonal characteristics only serve to make voices and instruments reproduction more convincing.


If you want a pair of speakers that play really loudly without turning hard or edgy these would be an excellent choice. At higher levels their punch is deeply impressive, as is their depth and power at low frequencies.

Initially that price tag of over six grand looks a little steep for a pair of relatively conventional looking floorstanders.

But factor the built-in amplification, exotically engineered in-house drive units and the resultant exceptional sound quality and the SCM40A emerge as something of a high-end bargain.

Consider us smitten.

The Competition 

ProAc Response D40/R

Our Rating