ATC SCM7 v.3 loudspeaker Page 2

The SCM7 v.3 measures 11.8" H by 7.9" W by 9" D and weighs 15.4 lbs. It's a solid, hefty little speaker that looks quite different from and far more up-to-date than its predecessors. The footprint is no longer square. The sides curve out and back in toward the rear, in the modern-speaker lute, canoe, or truncated Coke-bottle look wherein the rear panel is narrower than the front. The SCM7's drivers are now flush-mounted in a fully veneered front panel. The precision of the driver cutouts is impressive. The veneers are, as before, grain-matched across the left and right speakers.

The stylish, all-metal, hex-mesh grille is a neutral, medium-light brown just a little darker than café au lait, and attaches by means of concealed magnet pairs. With these updates, the speaker's front looks far less cluttered when the grille is removed to reveal the 5" woofer and 1" tweeter. On the rear panel are two pairs of non-insulated binding posts for biwiring; jumpers are provided; and the speaker comes with a six-year warranty. In 2009, when I reviewed the SCM11, the SCM7 cost $1050/pair; the SCM7 v.3 costs $1499/pair in Cherry or Black Ash veneer.

ATC states that the SCM7 v.3's frequency response is 60Hz–22kHz, ±6dB; its sensitivity is a lowish 84dB/W/m, its nominal impedance 8 ohms. They claim that the SCM7 v.3's flat impedance curve presents an easy load to amplifiers (they recommend 50–200Wpc), that the woofer's motor assembly weighs nearly 7 lbs, and that the drivers are pair-matched to within 0.5dB.

The most notable experience with the ATCs driven by the 2.5Wpc Miniwatt amplifier was with Mark Hollis's sparse and moody Mark Hollis—the album with the rather unsettling (at least to me) cover image of a malformed loaf of Sardinian Easter Bread (CD, Hip-O 5376882)—another loan from the friend who'd lent me the Miniwatt. Perhaps he suspected that I needed a break from working my way through all of Deutsche Grammophon's Archiv Produktion 1947–2013 (55 CDs, Archiv Produktion 001833572). Which, by the way, is a phenomenal bargain. Thanks, Jorge.

Hollis's solo work was new to me, and I found it more engaging than what I'd heard from Talk Talk. That said, his music, which strikes me as a blend of Tom Waits and Brian Eno, is something I think I'll return to only infrequently. Background music for Campari and chitchat it is not.

When first set up, the ATC SCM7 v.3s sounded to me like promising speakers that definitely needed breaking in. Between lots of listening to the Archiv boxed set, sifting through a treasure trove of Mobile Fidelity Sound Lab SACD reissues, and keeping up with new releases, as well as daily thwackings with Ayre Acoustics' Irrational! But Efficacious System Enhancement CD Version 1.2, over the course of weeks, the SCM7's treble blended better with the midrange, and the sound as a whole opened up and calmed down. All of my substantive comments refer to the end state the SCM7 reached.

It was immediately apparent from the first application (at a moderately but not insanely high volume) of the Irrational! But Efficacious disc's "Full Glide Tone," which begins at 5Hz (!), that the SCM7 was, for its size, bombproof. The woofer's excursions at subsonic frequencies were just plain huge. And while no sound emerged, the lack of sounds of distress or mechanical noises was most impressive.


The woofer behaved as you might hope a 5" woofer with a magnet structure the size of its cone and a motor weighing 7 lbs would. A DIY speaker-designer friend witnessed one administration of the "Full Glide Tone" and spontaneously exclaimed his amazement at the robustness of the woofer's excursion, and at how low (especially for a sealed-box design), the woofer began to actually make sound.

The SCM7 deftly handled the "Channel Identification" and "Channel Phasing" tracks of Stereophile's Test CD 2 (Stereophile STPH004-2). Image specificity was excellent, and the difference between the in- and out-of-phase segments was as great as I've ever heard. I do have to call the SCM7's reproduction of JA's low electric-bass notes "respectable" rather than "convincing," and nowhere near flat at 41Hz, the frequency of the instrument's low open-E string. On the bass guitar tracks, the larger woofer, larger cabinet, and ported design of the Opera Callas that I reviewed in August 2013 carried the day. (I relied on aural memory; the Callases were shipped to JA before the SCM7s arrived.) However, the higher-frequency reaches of the "Full Glide Tone" indicated that the SCM7 had a noticeably more extended top end than the Callas.

The SCM7 offered pinpoint imaging. "Easy to Love," from Ella Fitzgerald's The Cole Porter Songbook, Volume Two (CD, Verve 821 990-2), was a prime example—and if you think that judging imaging with a monaural recording is cheating, then Esa-Pekka Salonen and the Philharmonia Orchestra's live recording of Schoenberg's Gurrelieder was just as impressive (SACD/CD, Signum SIGCD173). There were also excellent retrieval of detail in the frequency and time domains (the acoustic guitar in the title track of Joni Mitchell's Court and Spark [gold CD, DCC GZS 1025]); low distortion (the mechanical noises made by the ancient pipe organ played by Helmut Walcha in the Archiv set were quite apparent), and, overall a naturally musical sound. I listened to Roxy Music's Avalon (CD, Virgin 8 47460 2) straight through, three times in a row.

Especially rewarding was track 1 of Stile Antico's The Phoenix Rising (SACD/CD, Harmonia Mundi 807572), William Byrd's Ave verum corpus, precisely because the SCM7's lack of extension below the midbass was a nonissue with this recording of a cappella choral singing, allowing the ATCs to "romp like the mind of God."

When he measured the ATC SCM11, JA mentioned that "its measured behavior suggests it will work better when listened to fairly close," by which he was specifically referring to the SCM11's non-aggressive treble response and its lack of high-treble dispersion. As chancy a proposition as it may be to judge a new speaker against memories of the sound of a different speaker of the same family, I did get the impression that ATC's new, in-house–made tweeter was more extended and more linear in response than the tweeter I'd heard in the SCM11—or that the SCM11's crossover voicing had made it sound that way.

You can't have everything in a speaker that costs only $1500/pair. Obviously, a sealed-box speaker with a 5" woofer won't get anywhere near flat response at 41Hz (low E on an electric bass) or 32Hz (low C on a pipe organ) or 27.5Hz (low A on a piano). Furthermore, while the updated SCM7 has impressively low distortion—actually, it had no distortion that I could hear, which I attribute to the robustness of its woofer—it didn't match the resolving power of much more expensive two-way loudspeakers such as Vivid's Oval V1.5, which I wrote about in my October 2010 column. The V1.5 similarly lacks audible distortion but also sounds more transparent, with greater resolution of fine detail. At $7600/pair—five times the price of the ATC—it should.

Summing Up
The ATC SCM7 v.3 is an extremely competitive entry in the British Shoebox Monitor sweepstakes. That it's made in the UK by a company known for making professional monitors, and has first-class fit'n'finish and addictively engaging musicality, are strong arguments in its favor. I didn't have on hand a pair of KEF LS50s with which to compare the SCM7s. However, from what I recall of the sound of Harbeth's P3ESR—over which I exclaimed "Gloriosky!" in October 2005—the SCM7 v.3 was as listenable and enjoyable. While the Harbeth retains a bit of the LS3/5A's midrange sweetness, the updated SCM7 seems designed to be a thoroughly modern mini monitor. And the ATC costs $700 less per pair.

Well done, indeed, and highly recommended. I look forward to the arrival of ATC's SCM19.

ATC Loudspeaker Technology Ltd.
US distributor: Lone Mountain Audio
7340 Smoke Ranch Road, Suite A
Las Vegas, NV 89128
(702) 307-2727

Supperconductor's picture

Headline typo.

John Atkinson's picture

Thanks - JA

audiolab's picture

I know you are right in that low c on a piano is 27.5hz, I will not argue that low c on a bass guitar is 41hz (I do not know of such things), but who decided low c on an organ is 32hz. Any half decent sized organ in a cathedral or concert hall will have a 32ft stop that yields a low c of 16hz. Some people would point you to two organs in the world that have a 64ft stop that yields a low c of 8hz, some would even point out that technically one of those two could play a resultant tone of a 128ft stop resulting in a almost purely accademic low c 4hz. I am quite happy to settle with it at 16hz and what a wonderful note it is to !

John Atkinson's picture

audiolab wrote:
I will not argue that low c on a bass guitar is 41hz

The low E string (not C) on a bass guitar or double bass is tuned to 41.2Hz, but most of the energy lies an octave higher, at 82.4Hz. See fig.3 at

John Atkinson
Editor, Stereophile

jmsent's picture

In the absence of enclosure resonance as an explanation, that fairly substantial dip in the measurement between 600 and 1 kHz might be the result of a woofer "edge resonance". Surprising, given the pedigree of the company.

John Atkinson's picture

jmsent wrote:
that fairly substantial dip in the measurement between 600 and 1 kHz might be the result of a woofer "edge resonance".

I had wondered if that were the problem, but I thought that cone/surround termination problems occurred a little higher in frequency, between 1kHz and 3kHz.

John Atkinson

Editor, Stereophile

jmsent's picture

I would normally take place a bit higher up in frequency on a driver this size. But certain cone/surround combinations can push it down. But whatever the cause, that sharp dip is fairly severe, and I'm still surprised they'd let it go to market with this flaw.

RoryB's picture

Looking at the magnitude of the peak/dip couplet, which does look like a surround resonance (probably due to the relatively wide surround; a Klippel scanning laser vibrometer could reveal the true cause), it is visible in the graph but at +3/-3dB in magnitude, it is not terribly severe. At the lower frequency where it occurs, you are less likely to notice it. You might notice it more as a coloration if it occurred at 2-3 kHz, and more would need to be done to correct it. A thicker surround or a variable thickness surround could correct this problem, but it would reduce broadband sensitivity of the driver.

Bob Loblaw's picture

In the article the term active and powered to describe speakers with built-in amplification is used interchangably. They are not the same thing. An active speaker has an active crossover and 1 amplifier for each driver, such as with ATC's active speakers.

A powered speaker is a passive speaker with an amplifier built in. The Audioengine A5+ is a powered passive speaker.

Active speakers have several advantages over passive and powered passive speakers and it's a disservice to your readership not to acknowledge the difference when there are those out there who may not know better.

ryder's picture

I am well aware that small monitors cannot go too loud or too deep in the bass. Having said that, can this SCM7 v3 go loud without losing control at moderate to high volume levels? Can it go louder than say the Harbeth P3ESR?