Atlantic Technology AT-1 loudspeaker Page 2

To address these problems, Atlantic has modified the AT-1's tweeter in some important ways. Steve Feinstein: "The tweeter's diaphragm breathes into a rear chamber. This lowers the tweeter's resonance from around 1800Hz to about 900Hz. Next, the entire rear chamber is made from drawn aluminum, which acts as one huge heatsink with lots of surface area, to cool the tweeter really well. Finally, the tweeter's surround is a full 4mm [wide], which is akin to a small woofer having one of those really big surrounds. It lets the tweeter have good, long excursion for low distortion, with no danger of mechanical mishap." The tweeter is also connected to a three-way switch on the rear of the AT-1 that controls its output level through a simple resistive network. The "+" position raises the tweeter's entire range of operation (2–20kHz) 1.8dB from the center position; the "–" switch lowers it by 1.5dB.

Though designed in the US, the AT-1 is manufactured in China. It seems to be finished in high-gloss piano-black lacquer, but a closer look reveals, under multiple applications of clear coat, a layer of metallic flake. It's quite pretty. The speaker sits on four aluminum feet that widen its stance and stability and permit the use of floor spikes. The buyer must install the pane of smoked glass that fits into an inset in the speaker's top panel. Though this looked fine, I'm no fan of letting a loose piece of glass rest atop a speaker, even though there are rubber damping pads. Other than that, the fit, finish, and build quality of the AT-1 were excellent, and at a level far beyond its modest price.

An open letter to all loudspeaker manufacturers
Dear Sirs/Madams:

It has come to my attention in recent years that many of you (this includes you, Atlantic Technology) think it superswell to put cable binding posts in recessed boxes and alcoves on your speakers, thereby making it very difficult to attach speaker cables terminated in high-quality spades.

I cordially implore you to cease and desist. There is no reason for you to hide your terminals in some nook or cranny. It saves you no money, and makes my life a living hell. (I'm not overstating this.) I know you want me to use good speaker cables, but I can't fit my spades into the Hobbit holes where your speaker terminals live.

I also find this practice of hiding away speaker terminals discriminatory. I was born with a common genetic condition called RFF (Really Fat Fingers): My hands look like an opened package of raw Hillshire Farm bratwurst. I've seen the top specialists in the country, but they tell me there is no known cure for RFF. Currently I am forced to hire small neighborhood children to tighten down your binding posts for me. Is this what you want? Do you want me to run some sort of suburban audiophile sweatshop out of my listening room? For shame, speaker manufacturers—for shame!

So that all may enjoy the serenity of knowing that their cables are properly attached to your speakers, please go back to mounting your binding posts on a flat panel on the rear of the enclosure. It won't cost you any more money, and at last I'll feel like a fulfilled human being.

Hugs and kisses,
Erick Lichte

Setup
Setting up the AT-1s was easy. After giving the speakers a few hundred hours of break-in, I began to dial in their presence in my room. Sitting where my reference Revel Performa F30 speakers usually do, the AT-1s sounded very balanced and neutral. However, I wasn't quite getting the low-bass weight that JA and I had heard at CES. I moved the AT-1s about 4" closer to the front wall.

The AT-1s remained very well behaved as I moved them closer to my room's boundaries. Each inch closer brought out more low bass, without the usual thickening and sluggishness of the upper and midbass. I also ended up toeing the speakers out from my ears by 10–15°. This gave me the best soundstaging and treble balance (more on this later) without too much of a sacrifice in midrange neutrality, clarity, or openness. The AT-1s didn't require extreme fussiness in setup, but will easily reward those who take the time to set them up right.

Sound
I was immediately struck by the AT-1's nice, open midrange: Voices and instruments were presented with full-bodied sound and distinct timbral colors. Through the AT-1s, the Emerson Quartet's recording of J.S. Bach's The Art of the Fugue (CD, Deutsche Grammophon B0000908-02) was rendered with each instrument having a generosity of tone that was both gratifying and accurate. The Atlantic's midrange was nicely resolving and revealing, allowing me to follow each voice in these fugues. I also found the handoff from midrange to upper bass seamless, which really helped the body of each instrument's tone meld with the rest of the instrument's overtones.

Voices, too, sounded lovely through the AT-1s. Soprano Carolyn Sampson's fabulous singing in Eriks Ešenvalds' phenomenal Passion and Resurrection, with Stephen Layton conducting Polyphony and the Britten Sinfonia (CD, Hyperion CDA67796), was coherent and colorful. Though the AT-1's midrange wasn't quite as open, revealing, or neutral as that of my Revel Performa F30s, I thought the Atlantic Technology speakers did a bang-up job, especially for their price. They consistently made compelling music.

Sometimes a product is so good that a single slight deficiency seems a bigger deal than it actually is—so forgive me if I unduly pick apart the AT-1's tweeter and treble. First, the tweeter wasn't as airy or as extended as I'm used to hearing from the Revels. Even though I listened to the AT-1s with the grilles off, the top octave sounded a bit dull, which made the AT-1 lose a bit of its otherwise nice resolution in the midrange and bass. This wasn't a huge problem in and of itself—plenty of tweeters sound like this. However, the tweeter also was a touch hard in the low treble when pushed to realistic concert levels. Less-than-stellar-sounding recordings—such as Destroyer's Kaputt (CD, Merge MRG369), an intoxicating blend of 1980s yacht rock and stream-of-consciousness musings on America—were even tougher listens than usual through the AT-1s; that low-treble hardness made my listening sessions a touch more fatiguing.

I settled on listening to the AT-1s with their tweeters at the "–" setting, which alleviated some of the hardness and blended better with the midrange, but gave up more top-octave air. When I pushed the AT-1s to higher volumes, that tendency for hardness in the lower treble also flattened out the soundstage in this region, even with such good recordings as Pantha du Prince's This Bliss (CD, Dial CD09), lessening the wonderful illusion of space this recording can otherwise convey. To put this all in perspective: The AT-1's treble is not at all bad, especially at the price, but the rest of the speaker's performance is so good that this was the single area in which I found the Atlantic's performance slightly lacking.

The AT-1's bass was as impressive in my room as it had been at CES 2010—not only deep and powerful, but taut and tuneful. More than this, I found the quality of the bass to be more coherent than from most sealed or ported designs, especially as it seamlessly presented low, mid-, and upper bass with a coherence that passed over to the midrange without a blip. Cellos and double basses sounded full and natural, without a bit of that pipe-organ quality that they have through some ported designs, in which certain bass frequencies—usually those at or near the port resonance—have a fatter, looser quality than the rest of the low end. Sealed designs lack that pipe-organ quality, but tend to also lack ultimate bass power and the ability to lock on to a room. The Atlantic AT-1 offered the best of all possible worlds and approaches to bass reproduction, especially for a speaker of this size at this price.

Pantha du Prince's This Bliss truly was bliss through the Atlantic, with bass notes full of weight and speed and great articulation. The AT-1 also did a fine job of delineating each bass sound from the rest—synths sounded like synths, basses like basses, drums like drums, etc. And the speaker's ability to make the bass information in classical music, such as the Ešenvalds disc or the Emerson's The Art of the Fugue, sound as coherent and compelling as electronic fare and rock, was a rare treat. By the way, "Fit Song," from Cornelius's Sensuous (CD, Everloving/Warner Bros. EVE016), sounded as good as I remembered from CES. (JA would have liked it.) In my room, I got good extension down to the upper 20Hz region, with no bloat or tubbiness. Bravo H-PAS!

The AT-1s' soundstaging was very good, and in some ways bettered that of my Revel F30s. The Atlantics had an uncanny ability to "disappear," and threw a soundstage that was immersive and specific. However, when I pushed the AT-1s to higher volumes, their hardness in the lower treble caused the soundstage depth in that part of the audioband to become slightly shallower. On the AT-1's front and side panels, which are finished in metallic black-gloss paint, I subjectively found cabinet vibrations to be relatively minimal; the unfinished rear and top panels seemed to vibrate a bit more. Thankfully, I noticed no major colorations that could bee the fault of the cabinet.

Conclusions
Atlantic Technology's AT-1 is the bee's knees. It offers a colorful, open midrange; coherent, extended, and powerful bass; great fit'n'finish; and is relatively forgiving of room placement. Though I've been a little tough on the AT-1's treble performance, it's entirely in line with that of other speakers costing $2499/pair—and the AT-1 gives many speakers costing twice as much a real run for their money. Though some of those $5000/pair speakers will do this or that thing better, they likely won't be able to do everything as well—and they likely won't have the AT-1's bass quality or quantity.

COMPANY INFO
Atlantic Technology
343 Vanderbilt Avenue
Norwood, MA 02062
(781) 762-6300
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COMMENTS
mrplankton2u's picture

The above speaker is a decent performer - for a bass reflex. However,  there is nothing unique, patent worthy, or even new about the design. PMC has been using resonance traps in its speakers for years.The "patent" shows a tapered transmission line shape with an anti resonance trap whose opening is located at a pinch point within the line. The distortion measurements shown in the patent are as misleading as the marketing hype for this speaker - distortion figures are presented only for select frequencies  to make it look better on paper than it really is. In fact, the impedance plot shows the telltale sign of an anti resonance trap - a impedance peak around 100hz. This is actually not a good thing. If you were to measure THD at that frequency, you'd find a noticeable increase. "Anti resonance traps" or acoustic filters have been around since the beginning of transmission lines. Their use actually demonstrates a lack of knowledge/skill in design - not an advancement. 

Moreover, the claims of mixing bass reflex with transmission line are totally bogus. True transmission lines possess a gradual 12db per octave rolloff in the bass region below the transducer's Fs or fundamental resonant frequency. This speaker clearly does not. It's rolloff is representative of a reflex design (steeper 24 db/octave roll off below transducer resonance). Compare the low frequency response of this to that of the Vivid Giya "quasi" transmission lines:

http://www.stereophile.com/content/vivid-audio-g1giya-loudspeaker-measur...

 

What this AT speaker is is a bass reflex with a small horn attached to the port opening and an acoustical filter incorporated to help dampen the upper resonances of a primitive design. Phil is just warming over a 25 year old transmission line patent with the application of an internal restrictor.  

Despite the false claims of this speaker's "designers", there is no continuum between a true transmission line and a pseudo "mass loaded transmission line". Mass loading means bass reflex - PERIOD. The velocity of low pressure pulses escaping a transmission line should be in the neighborhood of 340 m/s. The velocity of air transfer in most reflex designs is about 18- 20 meters per second (notice I said "air transfer" - not low pressure acoustical pulses - big, big difference). The mechanical tuning of a reflex design is centered about a Helmholtz resonance - a slug of air being forced through a restrictive pipe. The time it takes to ram the air slug through the restrictor determines the tuning frequency. With a transmission line, there is not supposed to be any "restriction" beyond the slight tapering of the cavity behind the speaker diaphragm that follows the natural reduction in acoustic pressure that occurs when sound radiates a given distance from its source (the 1/distance attenuation rule). The timing (frequency tuning) of a transmission line is established by distance from the source and the frequency whose peak presssure occurs at that distance. Contrary to now unfortunately common assertions, the two approaches can't be mixed. You either have restrictive timing and the inherent 24 db/octave rolloff or you don't.The design concepts are worlds apart and so are the results - particularly when you attempt to feed both designs with sub bass programme material at high volume. The reflex design unloads (over excursion) below tuning frequency and the transmission line just keeps humming along. The frequency response and impedance plots always give them away.

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