Reviews of Attainable Hi-Fi & Home-Theater Equipment

Reviews of Attainable Hi-Fi & Home-Theater Equipment

Atlantic Technology AT-1Great BuyI wrote recently about how, concerning their new DM 3/7 loudspeaker, Dynaudio may have struggled to find anything new and exciting to crow about. The DM 3/7 sounds wonderful, to be sure, but even Dynaudio’s own publicity department was at pains to find anything new or cutting-edge about the speaker’s design. I wondered whether that could be chalked up to the high cost of European manufacture, which will account for a good bit of the speaker’s price of $1995 USD per pair. 

Atlantic Technology, on the other hand, fills literal pages with news about the technology it has included in its AT-1 model, specifically its Hybrid Pressure Acceleration System (H-PAS). With H-PAS, Atlantic claims to achieve, in a single loudspeaker, the somewhat contradictory goals of truly deep bass, high sensitivity, and reasonable cabinet size. That this technology, which appears to be neither cheap nor easy to implement, is attempted in a speaker that retails for $2500/pair means that, you guessed it, the AT-1 is built in China. The AT-1 may seem to possess advantages that no speaker made in North America or Europe can hope to match, at least for now. 


H-PAS (patent pending) is well described in Atlantic Technology’s literature. Briefly, it combines in a single loudspeaker elements of bass-reflex, acoustic-suspension, inverse-horn, and transmission-line design, to “pressure and accelerate” the low-frequency soundwaves generated by the two relatively small (5.25") woofers mounted on the surface of the upper front baffle in D’Appolito style; i.e., one above and one below a single, 1.1” silk-dome tweeter. All three drivers are asked to do a great deal in this two-way design, especially the tweeter, which comes online at the relatively low crossover frequency of 2kHz. On their website, Atlantic provides a glimpse of the complex H-PAS internal chambering in an animated cutaway diagram. It’s impressive, and illustrates the invisible yet expensive features that separate high-end audio components from crap. Rule of thumb: If the component is any good, you should be paying more for what you can’t see, not what you can. 

Why all the expense and bother? Those small woofers, that’s why. To get good bass you need to move a lot of air, and to do that you need large-diameter woofers. But a bigger woofer cone means more mass, which in turn means a driver that’s less responsive; that is, a driver that’s more difficult to stop, start, accelerate, and decelerate as it reconstructs a soundwave. All else being equal, this presents a power amp with a tougher load, increasing the chance that transient details will be smeared. Although the size of the AT-1’s woofers is not unusual, the combination of the facts that the speaker has only two of them and a claimed frequency response of usable bass extension down to 29Hz, ±2dB, is fairly remarkable. 

According to Atlantic Technology, "the internal matrix of the cabinet takes the backwave of the driver below its resonance and pressurizes and accelerates it before it exits the vent. This acceleration increases the impact of the highly pressurized air flow in the enclosure when it leaves the vent. The result is both extended low bass and greatly improved dynamic range at such lower frequencies. The internal workings of the cabinet (using very specific, mathematically derived ratios between the various cabinet/driver relationships) are such that the low-frequency efficiency of the system actually increases with decreasing frequency -- exactly the opposite of conventional system behavior, where output below resonance drops rapidly. H-PAS produces a reciprocal output of the high-resonance drivers’ natural rolloff, yielding flat acoustic response to well below that of conventional designs using like-sized drivers and cabinets.” Atlantic Technology also claims less than 3% harmonic bass distortion for the AT-1, thanks to an “internal passive resonance/harmonic distortion line filter.” And, fear not, the soundwaves generated by H-PAS are in phase with those generated directly by the woofers. 

All this clever engineering promises some big payoffs for the listener, including a “yes, you read that right” claimed frequency response of 29Hz-20kHz, ±2dB, a highish sensitivity of 89dB, and a nominal impedance of 6 ohms. While at 41”H x 8.9”W x 13.6"D and 54 pounds the AT-1 isn’t especially small or light, it’s reasonably compact, especially in light of what it’s claimed to do. Along with the promise of high performance are such useful and welcome touches as the ability to biwire or biamp, brackets for taming wayward speaker cables, and something now rarely seen: a tweeter-level switch, in the form of a three-way toggle marked “0” (neutral), “+” and “-.” Altogether, the result is a real-world speaker in terms of both price and logistical requirements that promises world-class performance. 

AT-1 binding posts

But if Atlantic Technology has spent money on parts of the AT-1 that you’ll never see, don’t expect to find any visible evidence of their having saved any money. Not only is the AT-1 an astonishingly well-put-together and well-finished loudspeaker, it’s also one of the most thoughtful designs I’ve seen. I can’t speak for the other kind, but the reality for the audiophile who throws a party attended by real people for fellowship and good conversation is that any drinks served may find themselves set down on any convenient flat surface. I’d guess that the folks at Atlantic know parties -- the AT-1 comes Animal House ready with a ring-proof glass top (isolated from the speaker’s MDF cabinet by sticky rubber disks) and an easily removable, heavy-duty metal grille. While the AT-1 may not appeal to those who appreciate the beauty of nature as expressed in finely finished real-wood grain, I thought it looked lovely in its own right, finished on three sides in hand-polished, metal-flake, gloss-black paint -- which is easy to keep clean. 

Use and listening 

I cringe whenever I read a review in which the subject loudspeaker proved an absolute bear to set up and position for optimal performance. Yes, audiophilia is one of the finer pursuits, but if it’s tough to get a speaker to jell in a not atypical listening room, I’m forced to wonder what sort of space it was designed to work with. Atlantic Technology recommends placing the AT-1s 6’ to 10’ apart and 1’ from the front wall to start; to increase the bass balance, move them closer to the wall. I ended up with the speakers about 6’ apart, 2’ from the front wall, and 3’ from the sidewalls. So positioned, they gave me the flattest frequency response I’ve experienced with any speakers in my room. 

Aside from the 50Hz dip that seems to plague my room (in this case, -13dB relative to 1kHz), the AT-1s’ overall frequency response deviated only ±4dB from 32Hz to 10kHz, the maximum range my RadioShack SPL meter allows me to measure. This result was obtained with the speakers’ grilles removed; leaving them on made for a much more ragged curve. The effect of the treble-control switch was subtle, almost negligible in the “+” position; at the “-“ setting, I measured a cut of about 7dB beginning at 10kHz. Atlantic suggests using amplifiers with power ratings of 20-200W; I got excellent results with 50Wpc.

Ink has been spilled concerning the alleged tight confines of the AT-1’s recessed terminal panel. I had no problems in this regard, but then, I didn’t use cables that retailed for more than the cost of the speakers (though that’s not to say the AT-1 would be unworthy of such largess). As far as I’m concerned, Atlantic’s terminal design worked just fine at keeping the positive and negative leads apart while offering some protection against accidental shorts, all without having to revert to one of the fully encased Euro-nanny designs, which are frustratingly difficult to use. 

It is commonly suggested that loudspeakers that are particularly good with recordings of jazz but not rock, or as having a special way with classical music but that fail to deliver the goods when it comes to getting funky with James Brown, may have been voiced to sound good only with certain types of music. By definition, such designs will not be entirely neutral transducers. I would suggest that the opposite may be true, at least for some examples: that the speakers themselves are neutral, but that the listener’s expectations of how certain recordings and even whole genres of recorded music should sound are not. We might expect and even yearn for huge, bombastic, even out-of-control bass from John Paul Jones on Led Zeppelin’s first, eponymous album (LP, Atlantic SD 19126) -- after all, Led Zep was a huge, bombastic, out-of-control rock band. We may then seek a playback system (there are plenty out there) that will give us the results we want. But what do we now have? Our expectations of what Led Zep’s first album should sound like may have been met, but whether or not the system’s fulfillment of those expectations is what the artists actually intended is anyone’s guess. 

The AT-1 is one of those speakers that, instead of meeting expectations, tell it like it is. For Led Zep, that means that “Good Times Bad Times” was not the stupidly visceral rocker we imagine it to be, but a stunning re-creation of a masterful performance by four virtuosos. In the same way, the big bass was not so big in “Daughter,” from Pearl Jam’s Vs. (CD, Epic ZK 53136), as I’ve heard through my far more colored Snell EII speakers. Then again, I haven’t heard the band presented so well as individual musicians comprising a whole. There were now yards of space between Eddie Vedder’s voice and the rest of the band in “Elderly Woman Behind the Counter in a Small Town.” 

Atlantic’s great achievement in H-PAS is that such highly processed and massaged bass can be at once strong, tight, and detailed. I had no doubt at all that a double bass was one of the five instruments in Schubert’s “Trout” Quintet (CD, Sony Classical 5128722); through the AT-1s, the instrument had a good sense of weight, along with an excellent portrayal of its size. And when bass guitarists play lots of notes in a short amount of time, as John Wetton does in King Crimson’s Starless and Bible Black (LP, Atlantic SD 7298), nothing but a laser-fast propagation of the notes will do. And that’s exactly what the AT-1s gave me. And that low, low organ-pedal C on which the fanfare is built in Richard Strauss’s Also sprach Zarathustra (CD, Deutsche Grammophon 423 576-2) was truly subterranean -- although its level was in scale with that of the brass instruments, which were in no way smeared by these subterranean rumblings. 

AT-1 tweeter

And what about that tweeter? Though Atlantic doesn’t give it anywhere near the publicity it lavishes on H-PAS, that 1.1” silk dome is an extraordinarily fine thing in itself. Only the Legacy Studio HD may better the AT-1 in treble detail, but not having heard the Legacy in a while, I may be wrong even about that. The separation of the hi-hat and tambourine in “The Ballad of Peter Pumpkinhead,” from XTC’s Nonsuch (CD, Virgin TOCP-65720), which I first heard so well through the Legacys, was also clearly presented by the AT-1s, proving just how well balanced a design the AT-1 is. Care was obviously taken in making sure this speaker sounded superb from top to bottom of the audioband. 

Not to forget the all-important midrange, the AT-1 had that covered as well. Well-recorded female voice, such as Corinne Bailey Rae’s on her self-titled debut album (CD, Capitol CDP 66361 2), was presented as if she were in my room giving a personal impromptu performance of “Like a Star.” I had almost the same, albeit unexpected reaction to “The Only Exception,” from Paramore’s Brand New Eyes (CD, FueledByRamen 518250-2), where it was obvious that less purist techniques had been used to capture Hayley Williams’ voice. Creepy to have disembodied voices in your listening room? Perhaps, but isn’t that the goal? 


The Atlantic Technology AT-1 is more costly than its closest competitor I’ve yet listened to, the $1995/pair Dynaudio DM 3/7, but the extra $505 buys a whole lot in terms of fit’n’finish and performance. The AT-1 just does more, both on paper and in the listening. Nothing about this speaker annoyed me in the least -- and usually I find something that does. To say that the AT-1 should worry other manufacturers is an understatement. Smart people will buy a pair for $2500; the same smart people would be justified in considering the AT-1 even if it cost two, three, or four times as much. 

. . . Ron Doering

Associated Equipment 

  • Speakers -- Snell EII
  • Integrated amplifier -- NAD C 325BEE
  • Sources -- Rotel RDD-980 CD transport, Meridian 203 DAC; Thorens TD 309 turntable, Shure V15 V-MR and Audio-Technica AT-95 B cartridges, Bellari VP-129 phono preamp
  • Interconnects -- Kimber PBJ, Cardas Cross (phono), Have Canare Digiflex Gold (75-ohm coax)
  • Speaker cables -- Kimber KWIK (12 gauge), home-brew RadioShack hookup wire
  • Headphones -- Sennheiser HD 600

Atlantic Technology AT-1 Loudspeakers
Price: $2500 USD per pair.
Warranty: Five years parts and labor.

Atlantic Technology
343 Vanderbilt Avenue
Norwood, MA 02062
Phone (781) 762-6300
Fax (781) 762-6868