ATC SCM40 Loudspeaker Review

Posted on 13th July, 2021

ATC SCM40 Loudspeaker Review

David Price loves the live sound of this compact floorstanding monitor…


SCM40 Loudspeaker


ATC SCM40 Review

In the wonderful world of loudspeakers, you don’t get more hardcore than ATC. The company has ploughed its own furrow imperiously since 1974, largely avoiding the fashion-conscious world of consumer audio and focusing instead on its growing number of pro clients around the world. Unlike many speaker makers, the company doesn’t update its model range every year. Indeed, its apparent disdain for stylistic trends seems to endear it to many customers – something that’s buttressed by the unusually long product life of its designs.

Yet the Gloucester-based English company’s appeal is more than just about being too cool for school – it’s the sound that seals the deal. It’s distinctive, and – how can I put this diplomatically? – not necessarily voiced to mainstream consumer tastes. You never forget you’re listening to a seriously engineered and purposeful product designed to get the job done. Some love it, and others seek solace in more vanilla sounding speakers…

The SCM40 floorstander doesn’t look or feel like any other loudspeaker in its price class for two reasons. First, it’s a true, old school 3-way design with ATC’s iconic (to speaker geeks like me, at least) 75mm dome midrange driver. Second, the cabinet is an infinite baffle type which is rare in any modern speaker these days, and last commonly seen back in the nineteen seventies!

ATC SCM40 Review

Dome midrange drivers are as rare as hens’ teeth – and again they were last ‘a thing’ back when ABBA and the Bee Gees were storming up the charts. Yet ATC has been happy to use versions of its own bespoke driver for many years, and it gets the job done with aplomb. It uses a hand-doped acrylic diaphragm and suspension system, using a “secret ATC formula”, whatever that is. It mates seamlessly to the company’s SH25-76 25mm dome tweeter, a relatively recent design. This has a doped polyester diaphragm and suspension, plus an alloy waveguide.

With both upper drivers being domes, they have similar acoustic properties to one another, which is ideal for maintaining the correct phase relationship between the critical midband and lower treble range, where the human ear is super-sensitive – especially around this speaker’s 3.5kHz upper crossover point. Several serious speakers have done this over the years, not least the Yamaha NS-1000Ms that I use as my daily reference. Most of the SCM40’s price rivals are not proper 3-way designs, but, those that are, use dome tweeters with cone midband drivers. This may be a decent cost-effective solution, but ATC and others would contend that it isn’t the intellectually correct one – at least for a box loudspeaker.

Beneath the two domes, we find the SCM40’s bass driver, which kicks in below 380Hz. It features a hand-coated paper pulp diaphragm selected for its low mass, damping and rigidity. Its modest 164mm diameter is surely a concession to the speaker’s basic packaging requirements; it’s designed as a relatively small footprint floorstander to appeal to modern aesthetic norms and must be a practical proposition for modern listening rooms. The woofer is as wide as will fit in its cabinet; anything bigger would mean a wider front baffle. ATC designers have minimised this compromise by making it as beefy as possible – if you pardon my technical jargon. The huge motor assembly goes some way to making up for the cone’s relatively small radiating area.

ATC SCM40 Review

The cabinet is a nice, sensible size at 980x370x305mm, and as its name suggests, has an internal volume of 40 litres. Yet, that modestly sized bass driver and infinite baffle loading drop the sensitivity of the SCM40 down a bit. Designer Billy Woodman told me that the infinite baffle loading, “gets control over the bass driver across its complete operating band, and in turn reduces non-linear distortion. The 12dB per octave rollout associated with an IB also provides a fantastic transient response, resulting in a bass that sounds tight, controlled and fully representative of the audio signal.”

In today’s world of powerful solid-state amplifiers, the SCM40’s lowish (quoted) 85dB/1w/1m sensitivity isn’t that big a deal – especially as its nominal impedance is said to be an amp-friendly 8 ohms – but you still need muscle to really tickle this speaker’s transducers. ATC recommends amplifiers between 75 to 300W per channel. Quoted frequency response is 48Hz to 22kHz (-6dB), the relative lack of bass extension being a function of both cabinet loading and woofer size. The three-element crossover – comprising a low pass filter, bandpass filter and high pass filter – is simpler than expected and achievable because the drivers are designed around it, says Billy. The 31kg cabinet comes in a choice of four finishes and is beautifully made; few speakers at this price feel anywhere near as solid to the touch.

ATC SCM40 Review

Thanks to the lack of a bass port, the SCM40 is easier to position in a listening room than you might think. I ran my review pair just 30cm from my rear wall, slightly toed in. A range of amplification was used, from a gutsy NAD 3155 integrated amp to my Sony TA-E86B/TA-N86B pre-power in Class AB mode, putting out about 100W per side. A Cyrus CD Xt Signature silver disc transport was used, feeding a Chord Hugo TT2 DAC. I found this speaker needed a little more running in than is usual and sure likes a bit of power to really sing.


ATC speakers sound quite distinct, and the SCM40 is no exception. Let’s get away from naive notions of great speakers being ‘open windows on to the world’, shall we because they all have their own sonic fingerprints. You can’t call this floorstander perfectly tonally neutral, but it does have some extremely endearing traits that are hard not to love. Indeed, it’s the sort of speaker that – once you’ve heard it – reminds you what all its price rivals are getting wrong. It is exceptionally good at capturing the music’s natural timing – for a box speaker of this price – and the result is a gutsy, feisty and gnarly sound that’s about power and poise.

ATC SCM40 Review

It has a relatively even frequency response, with no particular areas in the bass, midband or treble that stick out at you. Even better, every bit of the spectrum works in concert with every other; there’s no sense of the bass arriving a little later than the treble, for example. The result is a cohesive, all-of-a-piece sound with precise image location. The speaker is very well integrated, tight, taut and together – so much so that you almost find yourself trying to provoke it into falling apart by playing ever more complex programme material.

For example, spin up Dance on a Volcano by Genesis, and this slice of mid-nineteen seventies rock absolutely hits the spot. It’s a dramatic sound with firecracker dynamics coming from Phil Collins’ drum kit, which he smashes the hell out of from start to finish. Overlaid is the delicate but inspired guitar work of Steve Hackett, plus washes of keyboards, bass guitar, and vocals. It’s a big, complex, multi-layered prog extravaganza, and the SCM40 absolutely loved it. I heard great scale, insight and detail, but most of all, I was beguiled by the bass.

I can’t think of any competitor that offers its combination of articulation and precision at the bottom end. It’s gutsy, visceral, powerful, yet doesn’t sound in the least bit overblown; it can start and stop with great alacrity; there’s no sense of overhang. Instead, it integrates perfectly with what’s going on further up the scale. The result is a sensation that’s hard to describe, but when you switch over to one of the SCM40’s reflex-loaded rivals, it almost seems like someone has added a touch of reverb to the recording, especially lower down. You lose that crunchy, tightly etched quality that’s unique to a properly executed infinite baffle box loudspeaker. This is a joy to behold, and of course, is clear to hear with every type of programme material you choose to play.

ATC SCM40 Review

The louche seventies soul sounds of Bobby Womack’s Across 110 Street are a long way from the Genesis track in mood, but I could still hear this ATC speaker working its magic. More obvious here, though, was the SCM40’s integration doing its stuff – everything in the mix fitted together hand-in-glove, or so it seemed. That meant a lovely central stereo image for the vocal line, with the different instrumentalists very clearly defined behind.

I’ve heard tonally sweeter renditions of this song but rarely hear more involving ones – the ATC isn’t a sweet-sounding speaker, being too matter-of-fact for that. It won’t sugar the musical pill, yet somehow this doesn’t matter because it cuts to the musical heart of the matter, time after time. Some may find its tonality a little stark, but this is due to its naturally revealing nature. I found The Jam’s Smithers Jones quite an ear-opener because the SCM40 reminded me about the low-fi nature of the track, yet it seemed to uncork the energetic fizz of the band at its best. This speaker’s rendition of this new wave classic was visceral and gripping. It conveyed the sense of the band’s immense power – something that often manifested as a kind of coiled spring, keeping the song under tension until the band hit a dynamic climax.

The ATC had headroom and bandwidth to spare. I really ramped the power up on tracks like these, and the speaker got louder and louder with no complaint – indeed, it seemed to relish the challenge. It wasn’t until I was virtually blowing plaster off my ceiling that this speaker seemed to start compressing things – and that’s in my largish listening room, at least by UK standards. It’s this combination of clarity, precision, insight and poise – allied to a really gutsy delivery – that makes the SCM40 special, at least to my ears.

ATC SCM40 Review

So it’s all perfect, and this is the best floorstander in the world, then? Well, I wouldn’t say so because if you’re a lover of natural instrumental timbre then the ATC is found a little wanting. To my ears, it imbues every recording it touches with a slight dryness – it’s as if the colour saturation control is edged down slightly to make it tonally somewhat more black and white. With classic rock recordings – which are often quite dry anyway – this isn’t a big deal, but musical genres like soul lose a little of their warm, inviting quality. I’m thinking of Marvin Gaye’s What’s Going On here, for example. There’s just a slight sense that it’s not so sweet and sumptuous as it should be. It’s not a profound sensation by any means – and some might even like it that way – but this speaker’s midband tonality isn’t the most full-flavoured all the same.

The tweeter is very good in most respects, being fast, balanced and without any unpleasant facets to put you off listening. Yet, it doesn’t quite have the finesse of some speakers at this price. A delicately struck hi-hat cymbal from Rush’s Different Strings, for example, is superficially impressive with an etched and tactile ‘wooden stick on metal’ sound, yet there’s a subtle loss of atmosphere in the treble all the same. Again, in the SCM40’s defence, this is but a trifle because the track as a whole sounds wonderfully tight, powerful, engaging and emotive. It’s only when compared to the best of the rest at its price – such as Acoustic Energy’s AE520 – that it is found wanting.

What this all boils down to is that the ATC has a ‘pro’ sound which you may love or hate. It’s more dynamic, expressive and physical than most domestic speaker designs. It has much more of a live feel and gives a good taste of that thrill you experience when actually experiencing music as it’s being made. Yet it’s a little less ‘house trained’ than some rivals, lacking just a touch of finesse and delicacy of more domesticated designs. This is most evident with classical music, a genre whose emotion and power is well conveyed by the SCM40, but one that loses a little of its textural purity all the same. I loved hearing my Deutsche Grammophon pressing of Beethoven’s Pastoral Symphony (Karajan, Berlin Philharmonic), for example, but it was for its power, scale, passion and stereo imaging precision, rather than the sweet sound of those massed strings or the atmosphere of the concert hall.


ATC’s SCM40 will either confirm your prejudices about ‘pro’ speakers or confirm your prejudices about domestic ones. Personally, I adore it for its accuracy, speed and insight – the way it strings the rhythmic elements of the mix together, punching out the music’s emotion in a marvellously unconstrained way. You might call it a monster of rock, but it conveys the power and majesty of other musical genres just as well. It’s one of my favourite compact floorstanders, but as ever with loudspeakers, it is a case of ‘different strokes for different folks’ – so do audition a pair if you possibly can.

Visit ATC for more information


      David Price's avatar

      David Price

      David started his career in 1993 writing for Hi-Fi World and went on to edit the magazine for nearly a decade. He was then made Editor of Hi-Fi Choice and continued to freelance for it and Hi-Fi News until becoming StereoNET’s Editor-in-Chief.

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      Posted in: Hi-Fi Loudspeakers Floor Standing Applause Awards 2021
      Tags: atc 


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