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Positive Feedback ISSUE 39
september/october 2008



SCM20-2A loudspeakers

as reviewed by Larry Cox






GamuT L-5 speakers and ATC SCM 20-2A powered speakers.

E.A.R. 864 preamplifier both with a mix of NOS tubes.

Apogee Mini DAC, 24/96 DIY DAC. Amazon Model 2 turntable with a Moerch DP6 arm and a vdH retipped Koetsu Rosewood Standard, and a Audiopath 4 tonearm cable.

Ensemble Dynaflux interconnects and speaker cables, Oritek X-2, Silver Audio Silver Bullet 4.0's and Audiopath tonearm cable. Supra EFF-i balanced interconnect between preamp and powered speakers, Supra DAC cable with WBT connectors, Supra Lo-Rad Mains power cords as borrowed cables, Kubala Sosna Emotion power cords and interconnects.

A Lovan Classic Rack, Townshend Seismic Sink, assorted Vibrapods, Final Labs Daruma III isolation bearings, Black Diamond #3 and #4 cones, with Black Diamond Whatchamacallit's, DH Cones, Discsolution, ASC Tube Trap Bass Trap and assorted other stuff. I hear the differences these items make, but only use them to optimize if the review isn't going well. Too much work to swap out a piece and balance it on Darumas and then take that out and repeat the process. Using all these consistently is a pain as what works with one component isn't a welcome addition for another.


This is my ninth review of ATC products in twelve years, four varieties of amplification and five different speakers. I've had ATC speakers as my reference for about eight years. The line represents excellence; their entry level products and much more expensive products perform very similarly. I owned their entry level speaker, the SCM7s ($1375) and recently wrote about their SCM 100s Tower speakers ($26,500) and have owned or written about everything else ATC makes in between. The 100 sounds like a much bigger, more dynamic version of the 7s with scads more bass.

Said yet another way, the top of the line speakers aren't of a "better quality" sonically, in terms of resolution or truth of timbre, they're just a bigger speaker for larger spaces with greater costs, hence a higher price. They accomplish this because they make their own drivers and have been OEMs for some top line companies, e.g. ProAc. ATC speakers tend to be a set and forget product.

They remind me of the Acura Integra I had for 16 years; I loved it until the day I donated it to a charity. Among the things I loved about my Acura was a clutch that lasted 207,000 miles; cost me less than $1500 in repairs over its life, handled really well and was a pleasure to drive every day I owned it.

With both products, years into my ownership I found myself spontaneously smiling and laughing (yeah, I'm a bit off) at what a delight they were to own. Certainly I wish I had less expensive taste, but these provide pleasure in ownership over the long haul and without diminution in satisfaction over time. With ATC and Acura I have no sense of wishing for something better or different, it's like winning the lottery, with the prize being daily satisfaction instead of millions of dollars.

The ATC20-2A speakers here bear the new "modern" style enclosures, which my wife loves. This two driver design has a wire grill cover, with laminated side panels and aluminum panels on the rear that function as heat sinks. Heat sinks you ask? The "A" in the model designation indicates that the speaker is amplified, or in this case each speaker has two amplifiers, two hundred watts for the six inch driver and the one inch silk dome tweeter is powered by a fifty watt amplifier. Both amps operate in class "A" operation for two thirds of their operation.

The 20-2A speakers are actual "mini monitors," not just sized that way—their 60 pound weight is significant and you'll want substantial stands for them. Probably much of the software you listen to is mastered on ATC speakers— Their professional pedigree is reflected in their superb build quality. At one point during this review, my three year old climbed on the speakers to get at the DVD player causing the speakers to tumble to the ground—cutting sound and flushing my body with the wrong kind of adrenaline—fear my son would be an audio casualty!

Relieved that nothing happened to my son, I turned my attention to the speakers. Replacing them on their stands it appeared that all electrical connections were still good, but there was no sound. Oy! I thought, how bittersweet, relieved my son wasn't a pancake but the speakers were ruined!

A quick investigation revealed there was no electrical contact at the power cord. A simple reinsertion of the power cord into the speakers and I was back in business with the sound quality unchanged. It's a blessing to have such a durable build quality.

I have found writing this review rather difficult in that I feel I've said before of other ATC speakers the same thing I think of the powered SCM20-2A speakers. They're a very complete speaker, not requiring you turn a deaf ear to performance anomalies. Searching for faults is troublesome. They are omnivorous with regard to genre aren't finicky about placement and can image very well. They're as dynamic as nearly anything on the market (horns included) close to their size, when placed in the right size room, as they are well and properly powered. As powered speakers they play quietly very well, though do really shine at moderate to loud levels.

With amplification provided some might be concerned that they're "stuck" with ATC's on board amplification. While the amplification is not interchangeable, I hear no penalty here. The sound remains "rich" in timbre, the timbrel progression from violin to viola to cello is easily discerned, as are other timbres as shown by the following experience.

A Deutsche friend, Peter, who got audiophile fever from hearing my system purchased his own system. His is what many would consider a high-end system, it's all tubes with electrostats. It sounds quite good, though like many budding audiophiles, he's got too much bass and has sentenced himself to listening to female singers with small ensembles. He played an exceptional CD for me from Harmonia Mundi called The Voice.

In his system, the sound was beautiful, vocals were angelic and a soprano pitched female, only the femaleness was a little odd. The oddness got louder and louder until I was listening for something in the voice, at which time my friend told me "the voice" was Andreas Scholl. And, Scholl is a counter-tenor not a soprano. The confusion of female sounding vocals is part of his gig. And, make no mistake his high pitched, castrati-like voice is quite moving. It's an eerie experience listening to her only to find out it's a him!

My friend gave me his CD. Through the ATC 20-2A speakers in my system, the disguise is less complete and more of the male warmth comes through, pulling back the curtain a bit, in a way that is more revealing of the vocal originator. The vocals reveal a larger chest cavity as the source of the vocals and a bit of male "resonance" is shown off, and perhaps that provides a bit more humanity and a bit less of the angelic qualities. While it might seem a disappointment that Scholl's trick is undone, sonically it allowed me to appreciate the signer's accomplishment of crossing the line between male and female vocals. The truth revealed was more of a delight than the trick obscuring reality.

The ability to unravel music and performances is part of the delight of ATC as a brand and the 20-2A in particular. Sometimes for better you hear all that is going on, and sometimes for the "worse" you'll hear all that is going on. If you're looking for all of your recordings to be drippingly beautiful, look elsewhere. This speaker is not a Photoshop, airbrush makeover artist. The sound is like a live event, which will remind you that while a live event can sound incredible, it may not also be beautiful.

And so, I might say, ATC speakers are probably not for the faint hearted or for those in search of the golden bloom of beautiful sounding, if also highly colored speakers. While I love the presence of beauty in life and music, I assert the beauty should come from the performance or recording and not overlaid by an audio system. Let me thresh this point out.

It's natural that you might want your music system to produce beautiful sound, no argument here. But when a system always sounds beautiful, even on poor recordings, you're hearing a recording from behind the curtain of the system's colorations or "beauty." Yeah it's nice, for a while, much as oatmeal is good (pretend oatmeal is good for a moment) at every meal that "good" eventually wears and you're back on track for a new meal/coloration.

The 20-2A speakers reveal the exceptional recording and expose pedestrian recordings each as they are. This might sound like an unwelcome experience, who doesn't want consistent excellence? I'm for it; I just know that there are always qualitative differences in recordings and performances. In recordings, as in life, some days are better than others. Not every performance by Ella Fitzgerald is equally excellent, nor is every recording. Those differences should be discernible through a high end system, not obscured by lacquering the sound in "beauty." Certainly the 20-2A speakers reveal differences in ways that I think are musically significant.

So, bad recordings sound like real instruments recorded poorly, the difference is preserved and communicated. It's more like listening in person to a cello in a bright and reflective room; you are hearing the room more dominantly than in an optimal listening environment. The cello still retains a cello's timbre, but with the room added in, on top of the instrument, not in place of it. Differentiating this way is easy to do live, that ATC do it with recordings makes it easier to hear and enjoy poor recordings through the 20-2A speakers.

Another welcome attribute of the 20-2A speakers is that the timbre they reproduce isn't dependent upon listening to "safe" recordings at one volume level. Some speakers do timbre well within a particular, limited dynamic range, but if you change the volume level you also change their character. In this latter instance, timbre is pinched, like toothpaste emptying the fullness of a tube, or precarious and strained like standing on your "tippy toes" as the volume or dynamic swing of the music changes. Not so ATC speakers.

The 20-2A speakers provide the "room" for instruments to show their particular and peculiar attributes, to communicate the ebb and flow of music. Much as each instrument has its own timbre it also has its own dynamic range. Some have much more than others. What ATC speakers do so well is to allow each instrument the sonic space to swing at its own pace or level, while having the control to allow each instrument to maintain, simultaneously, their own timbre and dynamic swing.

This characteristic blends with ATC's delivery of detail, without stooping to brightening the timbrel balance. Remember the old ProAc Tablettes? I'm sure detail and imaging freaks loved those speakers, but I cannot imagine a music lover pausing to give them a second listen. ATC does timbre really well, and retains clarity through the important region of vocals, by avoiding an electrical cross-over in that region. The 20-2A's six inch woofer mechanically crosses over to the dome midrange so vocals escape the net of the crossover allowing recordings to reveal the minute nuances that distinguish singers easily and effortlessly. Low level details are present, but within their own envelope, e.g. scraping shoes at a live recording aren't as prominent as the music but easily revealed.


A concern I would expect a reader to have is, what is the penalty with built-in amplification? Or, are you stuck with the sonics of the speaker amplifier combination? Well ...yeah, just to be clear about it. Powered speakers limit choices, for sure. First, the ATCs use XLR connectors and as amplified speakers will need to be within a power cord's distance of a power source. I did not find using adapters to be a problem sonically.

There are the negatives: you'll be deprived of years searching for the ONE right amplifier on the planet, or trying to resolve whether to bi-amp the speaker or finding the one right, magical set of speaker cables and then wondering whether to shotgun the wiring, biwire, or single wire with jumpers. Yeah, the possibilities of speaker/amplifier/cables combinations are as endless as the number of items for sale on audiogon are. Powered speakers cut that craziness out of your path to satisfaction.

Here's what ATC argues you get with an active system - amplifiers designed and matched to the specific load to be driven, so the amplifiers operate within their optimal performance parameters due to a reduced bandwidth work. This can dramatically reduce intermodulation distortion, and with ATC powered speakers drops the noise floor up to 20dB, which is a HUGE benefit.

Active crossovers also mean that there are fewer lengths of wires between the amplifier and the drivers themselves. ATC argues further that the filtering response of an active speaker should be much superior to a passive crossover because it isn't subject to the same issues. It should be no surprise then that active systems will be about 6dB louder than the same power applied through a passive crossover. That says a lot about passive crossovers, and the dozens of feet of wire encapsulated in the crossover. For information from ATC on their active speakers, go to: and look at pages 16-17 for a more thorough description of the benefits of powered speakers.

This version of the 20s is a remarkable product. It is more extended than previous models in the treble region with a tweeter that extends to 25kHz. Previous ATC iterations sounded a bit soft on top. The newer iteration sounds more extended allowing more filigreed definition on top, providing a more open sounding treble as well as midrange.

Bass is clean, tight and really fast. Some recordings might lead you to think the 20-2As lack a bit of bass, largely because it is so tight. You'll not hear billowing bass. If bass were like a bed, the ATC's bottom end would be the Marine's bed that you could bounce a quarter off of. Put on a recording with the bass amped up, e.g. try out DVDs and you'll notice how much the bass is pumped up in comparison to music. One exceptional "two channel" recording, Reference Recordings' Gabriela Lena Frank: Mestizo Waltz (Keith Lockhart/Utah Symphony) demonstrates substantial bass in the 30Hz region, with a fullness to it that is quite satisfying, and surprising from a speaker of the 20-2A's size. Through ATC's 100A speakers, however, and the bass is room massaging, truly and awesome experience.

Yes, the 100A speakers showed the 20-2A's limitations, but at three times the cost and five times the space, who would be surprised. Owning a pair remains a thought experiment at this point, and expensive as the 20-2As are ($8300) they're way more affordable than the $26,100 SCM 100s.

In the past, I lamented my passive ATC 20's ability to image. Well, perhaps that was my fault. I tend to listen in the far field (well away from the speakers) and when music is "just playing" at our house, I'm often not even listening on axis in the "sweet spot." These are all the things you'd expect of someone who doesn't particularly care about imaging.

By some accident I found myself listening in the near field with the 20s going through the output of an Apogee Mini DAC, functioning as DAC and preamp. This proved revelatory and delivered an amazing feast of detail with as natural a sounding timbre as I've ever heard and with a stunning clarity on recordings that could be the Holy Grail for many audiophiles. So good were things, that I wanted to hear EVERYTHING. So, I moved closer and closer to the speakers until images and instruments snapped into a "visual" focus, letting me know in no uncertain terms that they are clearly a near-field speaker and image as well as anything I've heard when listened to in the correct position.

For what it's worth, there is a right position with regard to imaging, though they sound very enjoyable off axis too. Although I listen in the near field more often now, listening off axis and further away still provides a satisfying listening experience. There isn't a correct or incorrect seat to hear timbre properly. Nearly any seat delivers a realistic rendering of timbre not just the sweet spot. And this is part of what makes listening through ATCs a delight.

More Tweaking?

While you may be frozen out of swapping amplifiers with the powered 20s, you can fine tune the 20-2A's sound with different power cords and interconnects. I was very surprised by how much power cords altered the sound. Frankly, they made a larger difference in my system than interconnects. Generic DIY power cords cables were unexceptional. Supra's Lo-Rad Mains power cords were a step up, and Audience power cords were yet another, though, for my system, the horrifically expensive Kubala-Sosna Emotions ($925/2 meter) were the horses to own. The even more horrifically expensive balanced Kubala Emotion interconnects ($2750/meter) altered the sound substantially less. I was very surprised.

Other directions for experimenting are preamps. I've heard good things about Accuphase, Ayre and Plinius' pre-amplifiers as matches to ATCs. I also really liked the sound of ATC's CA2 preamplifier. Using the Kubala-Sosna interconnects (the same prices as the CA2), the sound was really satisfying, as with the Supra EFF-I interconnects. I heard none of the sand-papery quality I described in a review in these pages. ( If I didn't already own the E.A.R. Yoshino 864 I would have the CA2 on my list. It's a bit more up-front sounding, but not like an electrical shock. Its sound is bold, dynamic and it's very easy to follow musical lines. It also features remote control of volume and source and that's really attractive.

For over seven years, my choice of preamplifier has been an E.A.R. 864, a true balanced preamp. It is a chameleon changing colors as I change tubes. The stock 12AX7 tubes are quite solid state in sound. Brimar tubes warmed things up though softening the sound, while Amperexes retained the Brimar's warmth and provided a bit more definition, though my favorites were Mullard 12AX7. The Mullards retained the Amperex's "humanity" with even better definition. All let me "contour" the sound.

Running through various combinations, the 20-2As don't become soft and romantic speakers through different preamps, interconnects, or power cords, though changes are apparent. I found highly capacitive interconnects provided a more organic and realistic sound, rather than a sound that occurs like a microphone feed with the metallic sound that can attend that experience.

Their $8300 price may cause you to gasp a little, but keep in mind that the 20-2A speakers include four amplifiers, two active cross-over networks and require one less set of speaker cables, and given the cost of excellent speaker cables, that's welcome news. Though still expensive, the ATCs look like a relative bargain, if your wallet can find $8300 a bargain.

The speakers sound terrific at lower volumes, unlike their passive variety when underpowered, though if you are primarily a low volume listener, there are probably other candidates to investigate. ATCs do their thing with all genres with aplomb, like a smart high school student doing basic "multiplication tables;" they stay on track now matter what's thrown at them. You'll notice that the upgrade path for many ATC owners is to a bigger speaker, not a different brand.

The final note is that regrettably ATC are not available on every corner. You'll have to hunt them down in some of the rarer places. Check out Flat Earth Audio's website,, they're ATC's US importer. For more complete information, you can log on to ATC's site at It is a bit ironic that ATCs are so hard to find domestically, when they're so widely used by the people who record and make the music you listen to. Recommended? Absolutely. Larry Cox

ATC 100
Retail: $8300

Flat Earth Audio
web address: