Tough to find another speaker this size that recommends amps up to 300 watts. Yes, they’re inefficient and require more power than many similarly-sized speakers, but it’s indicative of extremely robust construction. Not surprising that a pro audio oriented company produces these -- in that world speakers are often used at high volumes for several hours a day; power handling, output and durability are thus high priorities.

The drivers in this two-way are ATCs own design. The mid-bass unit is unique -- a midrange dome nestled in a cone woofer. As with other ATCs that use this type of driver, the transparency through the middle is striking for a two-way. One suspects an advantage to not having a single cone handle the entire mid and low frequency spectrum.

The speaker also excels at bite and attack, but let’s backtrack to the facts. The SCM 11 measures 15”H x 8.3”W x 9.8”D, and weighs 19 pounds -- as noted almost exactly the size of a cinderblock and nearly 80 percent as heavy. The front baffle is curved to minimize diffraction, but all other edges are sharp. These are nicely veneered, plain-looking boxes -- wallflowers in looks but not performance. I used them primarily with my Meridian front end (598/G68) and Llano 200 wpc tube/ss hybrid amps in a medium-sized, acoustically treated room.

THE SOUND: I’ve listened extensively to ATC active 10-2s, 20-2s, and now these passive SCM11s. If you can call transparency, detail and dynamics a house sound, the SCM11s are ATC all the way. It’s easy to think upon first listen that ATCs are tilted towards higher frequencies and a little lean-sounding, but this is largely a trick of their transparency and accuracy. There’s no mid-bass bloat or overhang, and no coloration that passes for warmth. They also fill out over time -- as I’ve found with the 20-2s, bass response improved after 100 hours or so of use.

On Wilco’s Yankee Hotel Foxtrot, the guitars on ‘Heavy Metal Drummer’ come through extremely clean and invigorating, though cymbals flirt with mild scratchiness. Female voices shine with clarity and detail, yielding edge-of-your-seat presence on well-engineered, intimate performances such as Feist’s Mushaboom and Shelby Lynne’s Suit Yourself. And though it can’t energize the air like a large speaker, the SCM11 goes deep enough to satisfyingly capture Leonard Cohen’s bottom-of-the-well baritone on Ten New Songs.

All speakers sound better at higher volumes, but the 11s more so than most. They don’t quite come to life until turn it up a bit. Do so, and you find excellent bass definition and punch for a speaker this size, as well as extraordinary dynamic capability. These things can swing thanks to rock solid driver and cabinet construction. Hesitation gives way to mad glee as you realize these small speaker seem to ask for more and more volume. The appeal and payoff is not simply loudness capability; rather it’s the sound of power. You hear it with amplified live music at any volume, and the 11s convey this better than any passive speaker I’ve yet heard at their size and price.

My main gripe with the 11s is a slight flatness in their presentation. Left/right imaging is precise, but palpability, the feeling of instruments and voices blooming in the air in front of you, is not quite class-leading. The requisite detail is present, but not the depth. Couple this slight negative, with the excellent transparency the design offers, and some recordings come off a bit dry.

THE COMPETITION: It’s instructive to compare the SCM11s to ATC’s active designs, as well as to the other monitor-sized speakers I’ve reviewed, the Amphion Ion ($1350) and the Zu Tone ($1795). Roughly a third the size and a third less money, the Ions lack the room-filling volume and dynamic capability, as well as the bass extension of the SCM11s, but present greater image palpability and texture that lends an appealing body to their presentation. Moving up the Amphion line to the larger Helium2 and Argon2 might be a more apt comparison to the SCM11s. The Zu Tone, at about the same price and two and half-times as large, are not as extended, punchy down low or transparent as the SCM11s. However, they sound more lively at low volumes, equal the 11s dynamic strengths, and offer subtly better pace and timing. The choice, of course, is a matter of personal taste.

The ATC active 10-2s ($4200) and larger 20-2s ($7300) offer all the strengths of the SCM11, as well as the image depth and palpability the 11s subtly lack. Their presentation is more supple and full-blooded. I’ll guess this is a result of the greater phase coherency the active crossover allows. They also sound more transparent than the SCM11s, though it’s the champ in this regard among the passive designs I’ve reviewed. In addition, the Active 20 is notably smoother in the highs, but it’s a far more expensive speaker.

If transparency, dynamics, extension and resolution are your priorities, the SCM11 is tough to beat at its size/price. It’s revealing nature along with relative insensitivity requires a good quality, powerful amp. In a word, the ATC sound is truthful, and if you like it as I do, be sure to give their active designs a listen as well. Not only do you get the synergy of amps and drivers designed under one roof; you also gain the advantages of an active crossover which is substantial in this application. The price jump to the active 10-2s is significant, but add in the cost of an amp for the SCM11s and you'll largely or entirely close the gap. Can you name another company that manufactures its own drivers, amps, and preamps, creates custom designs for large installations and is a fixture in mixing studios throughout the world? Whether active or passive, you’re buying into unique engineering prowess if you go ATC.

ATC SCM11 $2000

Manufacturer’s website: ATC.GB.NET

US Distributor: WWW.FLATEARTHAUDIO.COM