Hardware Review

Tuesday, December 3, 2019
floor standing loudspeaker
Rahiel ‘Naz’ Nasir

It’s probably best not to wear socks whilst listening to the SCM40s – they’re only going to get blown off each time you fire-up these gorgeous floorstanders. Right from the outset, these hand-built speakers impress even before you get their drivers moving. They’re built using a curved cabinet design that adds a classic elegance, and our review pair was exquisitely finished in a cherry wood veneer (they can also be ordered in black ash veneer as well as a black or white satin finish). 

What’s more, the ’40s feel weighty and solid (ATC traditionally uses numbers in its speaker names to represent their internal cabinet volumes in litres). They feature a new cabinet design that has been developed to deliver more than just aesthetic appeal as each enclosure is braced and laminated for added strength and damping.

The SCM40s were first launched in 2013 as part of ATC’s ‘Entry Series’ range which also includes active models. The line-up is the first to use the company’s new SH25-76 soft dome tweeter, which utilises what’s described as a “unique dual suspension system that suppresses diaphragm rocking modes, even at high output levels”. 


As well as the 25mm soft dome tweeter, the three-way SCM40s (which can be tri-wired) also include ATC’s 75mm soft dome midrange driver (which was first developed in 1976) and a 164mm short bass driver. According to ATC, its driver design of a short edge-wound voice coil operating in a long magnetic gap ensures “exceptionally low” distortion throughout the operating band. The magnet assembly also has a hole through the pole, enabling air to be vented from under the dust cap. It’s claimed this cuts air flow noise at low frequencies while simultaneously increasing power handling and reliability. ATC adds that it has removed from all drive units the need for ferrofluids which, it reckons, can dry out over time and affect performance.

This company is known for its engineering knowhow, and all of this tech-talk certainly leaves you in no doubt that you get a lot of speaker for your money when it comes to the SCM40s, setting you up nicely for what comes next.

The ’40s have been designed to present an easy load for amps with 75W to 300W on tap, and I partnered them with ATC’s own SIA2-100, a combined DAC and integrated amp rated at 100W. I was in the mood to listen to Air and so loaded up their 2007 album, Pocket Symphony (using ATC’s CD2 CD player). Selecting the atmospheric track ‘Photograph’, the SCM40s instantly unleash a thunderous, wall-to-wall sound that instantly captivates and engulfs the listener. And the bass! To say these ATCs plunder the lower frequency depths is an understatement: they go further, mining subterranean frequencies and delivering them as a powerful backdrop to the soundscape that is created before you. 

The big and bold SCM40s belt out a sound that’s as Herculean as their solid looks and feel suggest. And just to be clear here, we’re not talking quantity over quality – these aren’t crude, stadium-style sonics that lack grace and subtlety. What these speakers truly excel at are dimension and imaging; singers are brought to the fore and you know exactly where they are, while instruments and backing vocalists appear in the sound stage with pinpoint accuracy. 


Some jazz proves the point here. Playing tracks from Gregory Porter’s 2016 album Take Me To The Alley, I was totally blown away by the atmosphere the SCM40s were able to produce, delivering ‘Holding On’ not only with great power but also with great intimacy. It was like the man was right there in my living room and singing just for me.

Track after track, these speakers consistently served up intricate detail, such as delicate percussive sounds on ‘The Power of Goodbye’ from Madonna’s William Orbit produced Ray of Light album (1998). In fact, ‘Happy Cycling’ from the Boards of Canada’s Peel Sessions EP, came across with a percussive muscularity that had not previously come to the fore (an effect that my cat Rumi found rather disconcerting). 

Downsides? Well, this is not a criticism of the ATCs as such, but they do need to be fed with high quality recordings if they are to give of their best. Don’t therefore think that they can turn a dull recording into gold – alchemy remains a myth. But fire-up some well-produced sounds and the SCM40s will leave you in no doubt that they are certainly magical.


Type: 3-way sealed-box / infinite baffle floorstanding loudspeaker
Tweeter: ATC 25mm neodymium
Midrange driver: ATC 75mm soft dome
Low frequency driver: ATC 164mm short coil
Recommended amplifier power:75-300W
Sensitivity: 85dB 1W @ 1metre
Nominal impedance: 8 Ohm
Crossover frequencies: 380Hz & 3.5kHz
Matched response: ±0.5dB
Frequency response (-6dB): 48Hz-22kHz
Dispersion: ±80° coherent horizontal, ±10° coherent vertical
Max SPL: 112dB
Connectors: binding posts/4mm plugs, tri-wire
Dimensions (HxWxD): 980 x 370 x 305mm (inc. foot plinth – spikes add 25mm to height)
Weight: 31kg

Manufacturer Details: 

T: +44 (0)1285 760561


Wow, at last, infinite baffle loudspeakers instead of baffles with a hole! Superior non waffle ports. About time too.

By mbic

By 2017, my 1997 purchased Ruark Crusader II speakers were having problems with the mid range domes starting to display distortion. Sadly Ruark no longer manufacture loudspeakers and hold no spares for their past products. SO...what to do.. I was searching for a 3 way replacement with the same discrete 3 way inputs to permit continued bi-amp tri-wired operating.
A fellow HiFi enthusiast pointed me in the direction of the ATC SCM40s. An audition was arranged at a suitable dealer, I was blown away and ordered a pair the same day! Have now had them since June 2018 and these are the BEST speakers that I have ever owned and the last ones that I will need before my “box”!
Friends who visit are just left shaking their heads when they hear them for the first time. As the EAR reviewer states, the Bass just drops through the floor, can I say that that specified 47hz Bass response is remarkably
modest as the ATCs go that much lower than my old Ruarks which were rated at 35hz.
I am making full use of the tri-wire inputs with each speaker tri-amped with a pair of British Audiolab 8000M monoblocs for the tweeter and mid range and an Audiolab 8300M for the Bass, preamped with the British 8000Q which 23 years on is still giving stirling service.
As the reviewer states, the ATC SCM40s are remarkably revealing of any source, CD or vinyl, they HATE...some of the dreadful modern over compressed so called remasters which are now popping up such as the dire recent reissues of Curved Air’s first three albums all recording dynamics just ripped away, manufactured for earbud and car listening rather than an audio system.
The only thing which saddens me about these ATC speakers is that I did not discover them years earlier.
I had some wonderful now passed on fellow audiophiles who would have been blown away by them.

From the above review did you find that the ATC SIA2-100 amp could drive the speakers properly as to enjoy all genres of music to full extent?

By Gandalf

That is most certainly the case. The active version of this speaker will deliver more control at higher levels and higher resolution at all levels but the SIA2-100 is more than up to the job of making all musical genres enjoyable.

Since my first report, I have upgraded my vinyl source.
My Michell Orbe and SME Series V arm combo are now complimented by a Van Den Hul Frog Gold cartridge feeding now to a Rega Aura phono preamp (given an excellent review on this platform)
Now fully run in, these new additions make my ATC SCM40s that much more spectacular!
And my word do these wunder speakers now sing.
In the review mention is made of excellent reproduction using a CD source, I suggest another listening session is essential using vinyl.
I have been purchasing new 180-200gm remastered half speed cut albums of late and the head shaking disbelief of what is projected from the ATCs is astounding.
As you mention about the clarity and bass, it was unbelievable with my 2019 purchased Marantz SA 10
Signature SACD player, but the phono upgrades have taken it to another level.
For rock, the half speed mastered vinyl reproduction of Queen’s Bohemian Rhapsody just blows you away, never mind socks being blown off, you have to be wearing a safety belt! Visiting friends just can’t believe what they are hearing and as you say, extraordinarily these are “entry” level speakers?
Classical vinyl listening benefits, the Philips label John Elliot Gardiner’s Handel’s Firework Music displays exemplary clarity of the period instruments and the ATCs give forth a previously unheard infrasound of bottom end strings. Another Philips label treat is Saint Saens Organ Symphony No.3, Ed Waart & the San Francisco Symphony Orchestra, the second movement has your stomach shaking as the BIG..organ pipes break into tune. It’s now over two years since I took delivery of
my ATC SCM40s and in a HiFi hobby since 1972, these have to have been my most important, best ever audio acquisition ever..Thank you ATC!!

Renieblas's picture

Hello Jason,

I saw you review on ATC Scm-40a with Naim 272 that convinced me to buy the Atc! For the streamer I still hesitating to move on with the Naim 272 or Cambridge Azur 851n or...?

If you think Naim is far above I would like to know which cable did you use ? RCA to XLR? Or 4 pin DIN to XLR? I struggle to find a company to get the right cable.

Many thanks !

Best regards,

Hi Stephane, Naim and ATC is a very good combination. The Naim adds a bit of the warmth which the very neutral ATCs don't go in for and the result is often sublime. So in short, if you can afford the Naim then go for it.

As for connection I used RCA to XLR as that was all I had but DIN to XLR would probably be better as it's Naim's preferred connector.

Renieblas's picture

Many thanks for your prompt feedback! Any store / Manufacturer recommendation to order this type of cable online?