Review: ATC SCM20PSL – Compact Speaker

Review: ATC SCM20PSL - Compact Speaker - Are they the best two-way full-range drivers in the world? ?? From a technical point of view, the answer is.....

The ATC SCM20PSL, the most compact and, at 5,500 euros per pair, the cheapest model in the Classic series from ATC Loudspeaker Technology Ltd., was not available in Germany for a long time. Compact loudspeakers in this price range are not necessarily blockbusters – after all, the hi-fi customer wants something for their money! However, this “more is more” attitude seems to be slowly changing.

I like compact speakers. They are less bulky in the living room than prominent floor-standing speakers for two reasons. Not because of the footprint – the space required on the floor is usually within the same range. But they are less dominant and optically leave more room. And they often sound (up into the middle to upper four-digit price range) better than comparably expensive floor-standing speakers in most relevant criteria – even if you add the costs for decent speaker stands.

This is a claim that not everyone may agree with. Still, if you think about it, there are already some arguments that speak for it: There are lower costs for housing and assembly, so the development and production budget can be invested in higher-quality ones Invest components. In most of the listening rooms of ordinary people, deep bass-capable loudspeakers can rarely be “extended” and, in the worst case, tend to boom. With more miniature loudspeakers, the developers usually have to coordinate fewer chassis in phase and timing. In addition, a smaller cabinet usually resonates less, and a smaller front often reflects less.

Frequently, a perceived sound that is open, clear, and precise results from all these circumstances. The visual advantages mentioned – and thus the potentially “more vertical house blessing” – are an additional factor in addition to easier mobility on the back.

WAF is that nice!

While mobility is a thing with “shelf boxes” weighing 18 kilograms each, I can confirm the theory with the visual factor from my experience. As soon as the SCM20PSL in the smooth, warm cherry wood veneer are freed from their shipping boxes, I hear “Oh, how beautiful! They’re staying with us, aren’t they?” from my better half. Well, we’ll see. First, we place the speakers next to my ATC SCM50PSL (15,500 euros) on the Solidsteel SS6 speaker stands.

The similarities are unmistakable at first glance. The siblings present themselves as right-angled, practical, and elegant – due to their smaller proportions. However, the SCM20 appears a decisive bit more elegant. The difference in size is also revealed in the knock test, where the SCM20PSL reveals less void space – one of the abovementioned benefits. And that is certainly not only due to the bitumen damping plates applied to the inside, which are ultimately used in both models but above all to the more compact design of our test subject. Those interested in the right finish can choose from four veneers and satin black or white lacquered surfaces.

The differences are more fundamental regarding the housing principle and the drivers. While the SCM50PSL is a bass reflex design with the ventilation opening playing to the front, ATC uses a closed housing for the SCM20, as in the smaller entry-level models. And although the same 25 mm silk dome with double suspension (Dual Suspension) called ATC SH25-76S is used in both Classic models, the design paths separate underneath.

But let’s stay with the tweeter for a moment: By installing a second suspension, the moving components should only vibrate in the axial direction (i.e., not wobble), suppressing vibration modes and ensuring less distortion .

The added stability this approach offers compared to conventional tweeter designs eliminates the need for ferrofluid to dampen wobble, ATC says. As a result, the magnetic gap can be reduced, allowing the tweeter to function optimally for longer and offering higher power handling than conventional designs. The drive of the tweeter consists of a “magnetically tempered” pole plate and a neodymium ring magnet, whose geometry has been individually optimized by ATC with the help of finite element analysis. With a flux density in the magnetic gap of over two Tesla, the magnet assembly of the SH25-76S is fully saturated and, therefore, free from the effects of flux modulation in the surrounding metal structure. Frequency response to over 20 kilohertz.

Instead of the bear nose typical of the Classic series and an (at least) 25-centimeter bass drum, the 18-millimeter thick baffle of the ATC SCM20, which is attached to the actual housing, has a 15-centimeter diameter bass-midrange driver. Its oversized dust cap is designed in such a way that it acts as a quasi-midrange driver in the sense of the 8-centimeter midrange dome of the larger Classic models. The principle: The higher frequencies transmitted by the driver cause only this dome (and not the cone-shaped “rest” of the membrane) to vibrate, improving the radiation behavior in the midrange.

ATC also uses the same principle for the compact models in the cheaper entry series (SCM7, 11, and 19). The driver of the SCM20PSL does not differ from that of the ATC SCM19 (3,300 euros). Both have ATC’s Super Linear technology (hence the SL in the name, the P means “passive”) with a 75 mm diameter, short voice coil in a long magnetic gap, i.e., an underhang drive. The advantage: the voice coil remains in the linear range of the magnetic field even with large membrane deflections, which should ensure constant operation even under high loads.

ATC does not waste many words about the crossover of the SCM20PSL. It is only said that it is a second-order design. The treble is separated from the midrange and bass with a slope of 12 dB per octave. Anyone who has ever seen a crossover from the ATC Classic series knows that the British spare no effort: Hardly any other loudspeaker I know of contains so much high-quality and largely self-specified and manufactured material (see our company report on ATC).

The speaker cables dock to the typical, stable ATC Classic terminals that accept banana plugs, spade lugs, or stranded wires. In the case of the SCM20PSL, we found a bi-wiring version that was supplied with metal bridges; you should remove them immediately and use an excellent bi-wiring cable or high-quality pieces of cable instead.

ATC SCM20PSL: listening test and comparisons

Of course, the ATC SCM20PSL can warm up for quite a while on my Norma audio combo consisting of the DAC preamplifier REVO SC-2 and stereo power amplifier PA-150. But not much has changed – at least compared to the SCM50PSL, which still showed sound changes even after half a year; the SCM20 is already fresh out of the box at what feels like 95 percent “there.” And the remaining percentage points are not too long in coming either: a good week after the first notes, the compact ones are ready to dance with the tester.


I know what your first question is: “Can the ATC SCM20PSL do anything in the bass?” The answer to that is: they can do everything they have to do. And that means: building a stable foundation on which musical structures can be credibly built. On the other hand, bone-shattering coarse dynamics and accurate deep bass cannot reasonably be demanded from such compact loudspeakers.

In plain language, the SCM20PSL produces a bass up to around 50 Hertz that is subjectively perceived as minimally slim but never lean. In my opinion, the impression that the ATC SCM20PSL is a bit slimmer in the bass than many other compacts in their league is mainly because they play neutrally up to the mentioned 50 Hertz, i.e., with a linear level and without a bass belly between 80 and 120 Hertz. You’re almost not used to it anymore. Just as seldom one hears how the lowest audible octave fades significantly linearly. This seems pleasantly natural in the actual listening room, and somehow you don’t even notice that there isn’t that much happening at the bottom.

The ATC SCM20PSL reproduces the massive bass drum in Brendan Perry’s “This Boy” a little tighter than the Magico A1 (12,000 euros) and certainly not entirely with the same physical impact – but in the overall view, hardly believable. Incidentally, with the SCM20PSL, the differences between my rather powerful speaker cable Ortofon Reference SPK Black and the Kimber 8PR just tested (619 euros) in the bass are understandable: In this setup, I prefer the richer (and more expensive) Ortofon.


Surprisingly, the small ATC can play loud and with coarse dynamic sovereignty. They are in no way inferior to their American competitors, who are more than twice as expensive in terms of level stability and macro sprinting ability – only the aforementioned Ooomph is a bit “nice.” However, they still bring more pressure than, for example, a Wilson Benesch P1.0 (8,000 euros ). Whether that can be a point of criticism depends on your requirements and the type of music you prefer.

Mid tonal

From the middle register, it gets tonally somehow… boring? No, that puts you ultimately on the wrong track. Listening to music with the ATC SCM20PSL is anything but that, but the description of their tonality could be summed up in one word in a very sober and unspectacular way: neutral. I rarely say this with such unqualified conviction of a speaker model. But that’s the way it is: Starting with the fundamental tone, I don’t recognize any deviation from an ideal based on naturalness as soon as the positioning in the room is correct.

“Ha! But one limitation!?” Please! A placement tailored to the loudspeakers is part of the little hi-fi basics. So: almost 50 centimeters from the rear wall, 2.1 meters apart, with a slight angle towards the listening position, which is a good three meters away from the speaker base – this is how my almost 25 square meters become an acoustically well-fitting Full Brogue Oxford.

Voices, whether male ( Jarvis Cocker on “Tearjerker” from the album Room 29 ) or female ( Diana Krall on “Temptation” from the album The Girl in the Other Room on Amazon), possess the perfect balance of body and air, solidity and openness. In this discipline, the small ATC SCM20PSL play more neutrally than the slimmer Wilson Benesch, almost even at the high level of their big siblings and thus in range with the Magico A1. What exactly is missing from the vocal performance of the SCM50PSL? A touch more dynamic headroom, an iota of openness, a dash of articulation detail. Nothing you would notice without a direct comparison, but it should be said.

Oh, right: the tones are all there, where they belong. The ATC brushes are not too pale and not too rich; romantic oil paintings with a warm undertone are not their thing. Such an accurate vote may not appeal to everyone, I think it’s great.

Treble, resolution, and fine dynamics

Speaking of details: Since the ATC SCM20PSL has the same tweeter model as the SCM50, I don’t expect any significant differences in the tweeter characteristics. However, this assumption is only partially confirmed: Yes, the tweeters play cleanly and calmly even in the small ATC, but they allow themselves a little more “pizzazz” here, appearing fresher and more concise than in the slightly milder SCM50PSL. So they are right on the neutral line because even if you might think that the treble is a bit louder when listening to the SCM20PSL for the first time, this is more due to the bass range without over-elevation, which softens a neutral treble and ” pampered hi-fi listening habits.”

Be that as it may, the freshness, freed from the heaviness of the bass, obviously awakens the spirit of discovery in the silk domes. In any case, I can’t say that there is any deficit compared to the SCM50 in terms of resolution; almost on the contrary: In Chick Corea’s “Return to Forever” from the album of the same name, the silk domes serve the metal percussion very detailed, lively, precise and without false one’s Restraint, which, despite being structurally identical to the siblings, brings them closer to the beryllium tweeters of the Magico A1. They work out a few more subtleties when, in Felix Labande’s “Dirty Nightgown” (Album: Dark Days Exit), the electronically generated effects buzz out of the domes at a dizzying speed. But here, too, there are more nuances.

The same applies to fine dynamic gradations: Both compact loudspeakers react so directly and are finely granulated to dynamic micro-variations like only a few other dynamically equipped models I know. There are the Wilson Benesch P1.0 and the Grandinote Mach 2R (from 6,600 euros) with their “super tweeter,” – but neither play as balanced as the ATC. Be it the stroking of drumsticks with the mallet, the brooms on the drum heads in Melanie De Blasio’s “With All My Love” (Listen to Album: No Deal), or the jingling of tubular bells in Snarky’s “Sing to the Moon.” Puppy feat. Laura Mvula (Album: Family Dinner Vol. 2) and Prince’s “Welcome 2 America” ​​from the album of the same name: The sensitivity of the ATC drivers is fascinating. And when the xylophone oscillates a thousand shades in space on “My Favorite Things” from Youn Sun Nah’s album Same Girl, I wonder how ATC, with its all-island manufacturing at this price point, can do it.

Spatiality and imaging ability

The differences between the compact Brits and the Magico A1 become more precise when interpreting spatial imaging. The Magicos tend towards the large room, towards the stadium stage – the ATC towards the more comfortable theater hall, even if not towards the puppet theatre.

What sets the A1, which is more than twice as expensive, apart is its ability to scale independently of the stage size, i.e., the ability to display sound events large and small, regardless of the dimensions of the surrounding virtual space of the recording – they also act as physical objects acoustically entirely out of the sound field. The ATC prefer a more compact, three-dimensionally well-defined representation of voices and (also large) instruments but adapts them to previously limited space in depth, top and bottom. The position of the boxes in the room is also a little easier to identify than with the expensive Magicos. However, I have no complaints because this more focused-concentrated than extensive presentation seems consistent.

Broadband Genes

And with the keyword “harmonious,” I come to the icing on the cake, which gives the sound cake that special touch: The tonal balance and the unbelievable temporal unity of the ATC SCM20PSL – together with its low-distortion cleanliness – result in a sound for experienced people who have outgrown the tonal storm and urge times Listener almost irresistible mixture.

Because instruments, voices, or structures never fray – even when the recording could encourage it, as in the beautiful “Iron Sky” from Paolo Nutini’s album Caustic Love. If a playback chain gives this clip-recorded track an ounce too little flesh and body or produces a touch too much distortion, it may not even make it to Charlie Chaplin’s poignant speech from The Big One at higher volumes Dictator”. And that would be a shame. Luckily, the ATC SCM20PSL walks the path between grounding substance and opening clarity so confidently that this danger doesn’t exist. And funk tracks like Stanley Clarkesrousing “Hot Fun” (album: School Days) seldom groove into the dancing legs as accurately as with the small ATCs – an unmistakable sign of almost perfect timing. Oh, how nice is that! However, one shouldn’t confuse this musical unity with the ability to create a brute “heavy metal wall of sound” because the little one can’t do that despite all the love. But that’s what the larger ATC models are for.


Are the ATC SCM20PSL the best two-way full-range drivers in the world? From a technical point of view, the answer is, of course, nonsense. Still, one could answer it like this in terms of sound: Hardly any other speaker that I know of in this price range plays so skilfully balanced, the timing is impeccable and musically so round and harmonious, whether it is a compact monitor or a floor-standing model. Anyone who would like to enjoy music in a relaxed manner without any antics, but with a high information content, without running the risk of eventually getting tired of listening, should risk an ear.

Techno, house, and steamroller metal are not the favorite genres of the ATC SCM20PSL, but they don’t sound like a travesty either. Natural instruments, subtle electro, pop, rock, and jazz work excellently, preferably in small and medium-sized rooms between 10 and 25 square meters.

From 50 brisk watts per channel, it should start with a sensible amplification department; ideally, over 100 watts should be present to explore the astonishing level and dynamic reserves of the not-overly-sensitive compact. In any case, the electronics should sound as neutral, natural, and dynamically free as possible so as not to disturb the balance of the ATC SCM20PSL.


  • Are tonally and in terms of timing exceptionally closed multi-way loudspeakers, which almost have something broadband-like, but without the disadvantages of such concepts.
  • Play precisely in the bass, appropriately powerful for their size and, due to the linearity, felt more slim than fat. The well-controlled (deep) bass, which is more profound than expected and very predictable, evenly falling, predestines it for small to medium-sized rooms, where it can be a problem solver.
  • Have a neutral, open midrange and treble, although the latter may appear fresh to one or the other listener who has no experience with neutral studio monitors.
  • Reproduce voices openly, clearly, and movingly authentically.
  • Play distortion-free and clean up to level regions that were hardly thought possible.
  • Paint timbres more objectively than romantically, i.e., always with the correct dosage and differentiation.
  • Of course, they don’t hit the drum with the physical force of larger floor-standing or compact loudspeakers in coarse dynamics, but they have sufficient “oomph.”
  • React exceptionally quickly and get straight to the impulse point. They play in a finely dynamic, stunningly differentiated, natural, and effortless manner. An absolute highlight.
  • Resolve high-frequency details and what happens in the middle and presence range surprisingly well for the price class.
  • They are not spatially excessive but limit the stage a little, especially to the rear, in favor of an intimate, well-defined image on and around the loudspeaker level.
  • They are exceptionally well made and an absolute haptic delight.


  • Model: ATC SCM20PSL
  • Concept: passive two-way compact box with closed housing
  • Pair price: 5,500 euros
  • Nominal Impedance: 8 ohms
  • Sensitivity: 85 dB (1 W/1 m)
  • Dimensions & Weight: 440 x 239 x 326 mm (H x W x D), 18 kg/each
  • Colours: satin black, satin white, walnut, oak, cherry, black ash veneer
  • Guarantee: 6 years