ATC SCM40A Review

My Story With ATC SCM40A

Reviewing ATC SCM40A is not something that I have been actively chasing. Let me explain… If you have read some of my reviews previously, you’ll know that I really like big and heavy speakers. For me, size and weight are synonyms of quality. I of course learned many times that these attributes don’t always guarantee a good sound, yet, I still find myself excited about hefty speakers… I found out about ATC over 15 years ago and I remember being really impressed by the execution of their drivers with significantly oversized magnet structures and heavy diecast baskets. Not to mention excessively large cabinets of the ATC SCM100 and ATC SCM150. Since then, I always had a soft spot for ATC, especially their larger constructions. Consequently, if I was going to purchase a set for a review on my website, it would likely be one of their larger models, and not the ATC SCM40A. However, when an opportunity presented itself for me to spend some time with ATC SCM40A, I could not really pass on it, hence this review.


Speaker Info

ATC is a UK based company that started its life in 1974 serving professional market, which then expanded to the domestic market. They are quite unique because they make their products in the UK, but what’s even more unique is that they make all of their drivers in the UK too! Not many business make their own drivers these days, and very few actually do it the UK.
ATC have a rather conservative approach to marketing, and as such, they release new loudspeaker models only every 5 to 10 years. ATC are also strong proponents of active speakers, which doesn’t always work well with audio enthusiasts, who like to tweak their sound by changing amplifiers. Because of these two factors, ATC is not very well known amongst audiophiles. I image that they are more known in the professional market, where large number of high end recording studios use ATC active monitors.

ATC SCM40A are the active version of their domestic speakers, ATC SCM40. It’s a 3 way design, where each driver has a separate class AB amplifier and the crossover is done in the analogue domain on low-level signals. As any other active speakers, ATC SCM40A have to be connected to the mains power supply (cable to each speaker) to power the amplifiers inside them. In terms of audio inputs, they only accept balanced signal (via XLR plug), so you will need to have a preamplifier with balanced outputs to drive them properly. This is a standard in professional market, however, it is not that common in domestic devices.

Driver-wise, ATC SMC40 are built around their 25mm soft dome tweeter and their famous 75mm midrange dome. Both of these drivers feature dual suspension, which according to ATC, suppresses rocking modes and ensures low distortion levels. ATC also claims that additional stability that this approach provides over more conventional tweeter construction, negates the need for ferro-fluid, which is often used in tweeters for damping and cooling.
Low frequencies are taken care of by a 164mm paper-cone woofer housed in a 40l sealed enclosure. This bass driver has a significantly oversized magnet structure and a short voice coil. This approach allows the voice coil to always remain within the linear magnetic field, which significantly contributes to reduction in distortion. Although this approach is technically sound, one of the reasons why we don’t see many driver manufacturers embracing it, is cost. Producing drivers like this is not cheap, and this is very much reflected in what ATC charges for their loudspeakers. I suppose, to some extent, you get what you pay for…


ATC SCM40A Specs

Frequency Response: 48 – 22,000Hz (+/- 3dB)
Sensitivity: N/A
Impedance: N/A
Built-In Amplifier: LF: Class AB 150W, MF: Class AB 60W, HF: Class AB 32W
High Frequency Driver: ATC 25mm Dual Suspension Soft Dome
Mid Frequency Driver: ATC 75mm Dual Suspension Soft Dome
Low Frequency Driver: ATC 164mm Short Coil Paper Cone Woofer
Crossover Frequencies: 380Hz & 3,500Hz
Enclosure Type: Closed
Enclosure Dimensions (HxWxD): 980x370x344mm (38.6×14.5×13.5″)
Enclosure Dimensions With Grill & Spikes (HxWxD): 1005x370x378mm (39.5×5.1×14.9″)
Weight: 36kg (each speaker)
Production Years: 2014 – Current
Price When Launched: £6,280 for a pair


Look & Feel of ATC SCM40A Speakers

The ATC SCM40A look like modern slim tower speakers, and this is exactly what they are. They have a nicely shaped cabinets finished in real wood veneer. I never liked the black version when I’ve seen it one the pictures, as they always looked a little bland to me. However, in real life I’m pleased to report that even in black, these speakers look very attractive. Look of the ATC SCM40A is definitely more house friendly than the square looking speakers from ATC’s Classic line-up, such as ATC SCM50A or ATC SCM100A. One thing I would criticise is that their cabinets are not as heavy duty as their drivers. Don’t get me wrong, there is probably nothing wrong with them, they just look somewhat anaemic in contrast to their drive units.

And speaking of drivers – these are real monsters, especially midrange and bass. The motor assembly of the midrange is actually larger than its faceplate, and this is also the reason why these midrange drivers have to be mounted from the inside of the enclosures. What’s not so great is the doping of the midrange dome – it rather sticky and it is going to attract dust, and I’m not sure how I’d go about cleaning it. I of course understand that this viscous damping medium is there for a reason, I just don’t think it’s very practical.

Overall, ATC SCM40A are very high quality loudspeakers.


Sound of ATC SCM40A Speakers

Whether we like it or not, we are all victims of conscious and unconscious biases, which often put a large question mark over sighted speaker comparisons. Before I commenced the review of ATC SCM40A, I was so excited about experiencing my first set active ATCs in my own environment, that deep down I already decided I was going to like it, no matter what. Not a good start but I just could not help myself!
I use currently use Magnepan 1.7i with dual subwoofers, and with parametric equalization as my main setup. I’m used to balanced sound with high resolution and fairly linear but extended low end. When I connected the ATC SCM40A for the first time, the thing that stood out straight away was that they generate a lot more energy in the top-end than what I was accustomed to. On tracks such as Miód by Męskie Granie Orkiestra from the Męskie Granie 2019 album, I could easily hear the distortion on the guitar riff at the beginning of the track when playing it through ATCs. In contrast, I could barely hear it on my main setup. On the other hand, ATC SCM40A made the very same song slightly edgy and not as easy to listen to, whereas it was quite pleasant to listen to on my main setup. First impression can be misleading, so I’ve moved my speakers out of the way and gave my ears some time to adjust to ATC presentation before commencing critical listening.

In my opinion, bass is a foundation of everything and the way speakers reproduce bass can often influence our perception of other frequencies. ATC SCM40A seem to produce a fairly impactful and dry bass. This is noticeable on songs such as Granda by Brodka, where these speakers definitely make your foot tap. Moreover, there are plenty of details in the bass, and this helps with reproduction of tracks such as Abyssinean Dub by Blue Asia, where the bass guitar sounds very well defined, and it is easy to follow. The extension of the bass is not bad considering their small internal volume (40l), however, its definitely not as deep as what I’m used to. If you like electronic music and get a lot of joy from experiencing lowest notes viscerally, then you will definitely need a subwoofer, or better yet, two. The character of bass generated by ATC SCM40A is probably more accurate than bass from a lot of other speakers, however, sometimes I wish their bass wasn’t as dry and had more ‘meet on the bones’. And it is not the bass extension that I’m referring to here, it’s it’s dryness. Saying that, it is plausible that I’m used to bass which is not as well controlled, and if I was to keep these speakers for longer, their dry bass would become my reference point.
One thing that disappointed me a little was lack of effortlessness. With many large 3-way speakers, I often get a feeling that their sound is very easy going, very effortless. I get a feeling that I could open up the volume control as far as possible, and the speakers would go “is this all what you have?”. I was expecting this sort of impressions from the ATC SCM40A but unfortunately this wasn’t really the case. Even though they have a pretty good impact, they do not sound effortless. Moreover, once I got them playing fairly loud, they seemed a little shouty, as if the speakers were reaching their limits. Again, the level I was playing them at is something that 99% of people wouldn’t do in their living rooms, so don’t hold this against the ATC SCM40A.

Midrange and treble are very detailed and accurate. In contract to many speakers, it seems that ATC SCM40A don’t impose their own tonal character onto the music. They play what was recorded without colouring it. Despite having a lot of output in the higher frequencies, sibilants on vocals are not emphasised, which is great. This indicates to me that what I perceive as extra top-end energy output, must be in the upper treble (i.e. above 6kHz). This would also explain why I could hear more ‘air’ on majority of live recordings. It is worth pointing out at this stage, that this extra top-end energy is very much depended on your listening environment. For instance, my room is relatively hard – concrete floor covered with laminate flooring. I have listened to the very same speakers in my friend’s room (suspended wooden floor covered with thick carpet), and the extra top-end energy wasn’t present there. I’m suspecting this may have something to do with relatively wide dispersion of the ATC SCM40A, and how the reflected sound influences the overall tonal balance in various rooms. In my room this was a double-edged sword. On songs such as No Woman No Cry from the Live! album by Bob Marley & The Wailers, presumably due to more harmonics in that area, it made me focus my attention of the cymbal from the drum kit. And it was to the point where that cymbal was distracting me from listening to and engaging with the track. In contract, in some cases this extra air adds to the atmosphere, and a great example of that is Chan Chan by Buena Vista Social Club which sounded very engaging on the ATC SCM40A. This track also made me appreciate how great these speakers are at throwing deep and well separated soundstage, which further enhances engagement with music.

However, it is not all rosy. In my room, likely as a result of that extra top end, ATC SCM40A are quite unforgiving. Great example of that is Hell Is for Children by Pat Benatar, which is a quite bright recording. When things got busy in the song, I had to turn it off as it was ear-piercing. That experience reminded me somewhat of the Yamaha NS-1000 M speakers, which were equally unforgiving of bad recordings. In contract, I used to use Harbeth M40.1 as my main speakers for couple of years, and on these, I could definitely listen to that track. Ok, it wasn’t fantastic, but I could still have an enjoyable experience, whereas that is not really possible with the ATC SCM40A in my living room.
Moreover, relatively flat sounding tracks such as Grey Street by Dave Matthews Band don’t sound very engaging on the ATC SCM40A. Again, these type of songs don’t sound very engaging on most loudspeakers, however, there as some speakers (i.e. KEF LS50 Wireless II) that present them in a way that makes them more engaging to listen to.

Overall, ATC SCM40A are very capable speakers providing that they are placed in the suitable environment. If I was going to use them in my relatively hard room, I would have use to parametric equalisation to reduce their treble output. On the other hand, my friend has a set of these in a fairly absorbent room and they sound very even-handed there.
In my experience, certain speakers (i.e. Harbeth) tend to sound pretty good regarding of the environment you put them in. This does not seem to be the case with these ATCs, so an audition in your own listening room is definitely a must if you are considering a set.




ATC SCM40A are very accurate and transparent sounding speakers. They are capable of creating deep and very broad soundstage. They can sound perfect in fairly absorbent rooms and too hot in more reflective rooms, so definitely listen to them in your own environment before you decide to purchase.

Balance of Sound: 3.5 grey stars
Neutrality of Tone: 4.5 grey stars
Transparency: 4.5 grey stars
Soundstage: 4.5 grey stars
Attack: 4 grey stars
Engagement: 3.5 grey stars
Total Score: 4 red stars


Songs Mentioned In This Review

Brodka – Granda
Blue Asia – Abyssinean Dub
Bob Marley & The Wailers – No Woman No Cry (Live)
Buena Vista Social Club – Chan Chan
Dave Matthews Band – Grey Street
Męskie Granie Orkiestra – Miód
Pat Benatar – Hell Is for Children


Reviewed: October 2022 | Published: December 2022

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