December 2009

World Premiere!
Acoustic Technologies Classic Series Loudspeaker
Focus and transparency from a small driver.
Review By Rick Becker
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  At CES, 2009, this Acoustic Technologies LLC single driver loudspeaker captivated my imagination and I quickly requested a review sample. I was fascinated by the inviting three dimensional sounds that covered a wide range of listening positions. Even fifteen feet to the right of the right speaker the music retained three-dimensionality. Its high efficiency meant my tube amplifiers could drive it with ease. But this was a new company and the design had not been finalized. I had to wait for a production sample.

Eventually, I settled for a pre-production pair which was shipped to me in a heavy duty plastic flight case since the production packaging had not yet been completed. This was a mistake. Plastic is slippery and packaging sent via UPS and FedEx must negotiate long trails of conveyors in the cross-docking warehouses. Spills are not uncommon, I'm told. It didn't take long for me to recognize that this pair did not have the magic I heard at CES. Perhaps it was the loose solder connection at one of the binding posts, I thought. I wanted to take the drivers out, too, so that I might check their soldered connections, but they required a special bit. David Lesht of A.T. quickly sent one to me. The connections at the drivers on the speaker with the loose binding post were not great, so I leaned on my friend Bill Tomkiewicz, who is a serious tweaker, to do the job for me. In the mean time, I also discovered the cabinet of the speaker was cracked at the seam where the side meets the bottom plate — clear evidence of shipping damage.

I left the speakers with Bill to be soldered and picked them up a week later. We auditioned them in his system and they seemed to be better, but not great. Bill shared a story of what happened during their stay at his home. Over the years he has swapped a lot of speakers in and out of his system. His wife, who is not an audiophile, never comments on any changes he makes to his rig. But she did when the A.T.s were put into the system. Listening from another room where she normally sits to read, she commented that they sounded "really good". I filed that away for future reference.

Back home, further listening confirmed that there was indeed an improvement, but the speakers still lacked the magic I had heard at CES and far off axis, I did not have the holographic perception that was evident at CES. I contacted David Lesht again and he wanted to send me another pair, but could I wait until the new packaging had been finalized? Sure, why not? The Tekton Design monitors that were later awarded a Blue Note Award had arrived by this time, so I just changed trains for a couple of months.

When the new packaging was developed, several pairs had to be shipped out and returned to A.T. in Chicago to evaluate the success of the packaging. Eventually, it got the green light and a true production pair of speakers was sent to me. The delivery guy set them down in the store and I signed for them. Not until he was long gone did I discover on the side facing the wall (by chance?) there was a big hole in the box. I put my fist through the hole to feel for damage. There was just a tiny ding in the side wall of the speaker. Whew!

When I unboxed them at home that night the packaging was clearly over-engineered and under-effective. I've been told the packaging has since been beefed up. I set them up in the video rig and let Linda burn them in with her usual assortment of Netflix, Dancing with the Stars, Biggest Loser, and that pinnacle of democracy where people get voted off an island. If a speaker can pass that acid test, it is ready for my big rig.

Setting Them Up
Following the Tekton Design OB4.5 in my listening room is not an easy task. I was warned by an expert loudspeaker manufacturer that listening to an open baffle design with a full range driver may well spoil me for reviewing more conventional designs. The colorations of the A.T. cabinet were fully disclosed in comparison with the Tekton Design, but even beyond that, the A.T. was just not producing the kind of experience I remembered from CES. Not the focus, not the soundstaging, not the far off-axis listening experience that had enthralled me.

My friend Tom Lathrop was headed to the RMAF for the third time and I asked him to stop into the Acoustic Technologies room and take a photo of their set-up. In the photo he sent, the speakers didn't look like they were set up much differently than I had done. I had tried moving the speakers fore and aft in my wide listening room, but was not able to make a significant improvement. The RMAF photo seemed to indicate I had my pair about the same distance from the front wall as they did in Denver . I even went so far as to pull out a test CD to check for phase in the odd chance they had been wired incorrectly. Everything checked out fine. In desperation I called David Lesht and shared my frustration with him. He connected David Maeshiba, the designer of the speaker with us for a conference call. Mr. Maeshiba's background is in biomedical engineering for which he has taken many physiology courses giving him an extensive background in perception. DM started asking me about the distance between the speakers and the size of the room. Finally, he made the suggestion that I move the speakers closer together.

The Listening
It seemed counter-intuitive, but I moved the speakers closer together (from 8 to about 5 feet) and sure enough, the music snapped into greater focus. The soundstage became deeper as well as further recessed behind the plane of the speakers, but it narrowed down considerably, too. Moving fifteen feet to the right of the right speaker, finally, I had a similar experience to what I heard at CES where the image of the soundscape was still 3-D and positioned behind the plane of the speakers. The imaging is not pin point, but neither is the sweet spot for listening. In fact, three people on a sofa could easily be satisfied with the three dimensional imaging. When walking across the middle of the room from left to right the music seems to come from an area behind and between the loudspeakers. As I pass in front of the first speaker there is a shift where I became aware of sound coming from the speaker itself. Continuing on, as I pass between the speakers the distant soundstage is re-established until I pass in front of the second speaker. All-in-all, it makes a great speaker for a party situation where people are milling about, or for a dining situation if the speakers are in an adjacent room in a house with an open floor plan. It even sounds decent down the hall at the far end of the house when sitting in my home office!

From their literature before the speakers arrived, I noticed a similarity of the 3" full range driver with the Audience full range driver. Both use titanium cones and neodymium magnets, but the A.T. driver is sourced from China and is more modestly priced. It is quite efficient and was easily driven by my Manley Mahi monoblocks that put out about 13 watts into an 8 Ohm load such as this. Because it is a single driver, there is no crossover, of course. High purity solid silver wiring of 24 gauge is used within, and this same wire was used as speaker wire in their CES and RMAF presentations. Since it does not draw a lot of current, they can pull this trick off. A boondoggle weave of three wires was used in their demo to enable the wire to lie flat on the floor. A twisted pair has a tendency to curl up and pose a liability for tripping visitors. In actuality, only two wires were connected to the gold plated solid copper Cardas binding posts. From my DIY experiments in making my own interconnects I learned that 24 gauge silver plated copper mil-spec wire produced more highly focused music than the 18 gauge mil-spec wire I had previously been using. With this in mind, I made up a pair of speaker cables with 24 gauge mil-spec wire to replace my JPS Labs Super Conductor+ cables. The mil-spec wire gave me a little more energy at the top end, but switching back to the JPS cables some weeks later gave me a more relaxed presentation.

The A.T.s perform the disappearing act common to small stand mounted monitors very well. The footprint of the tower is similar to many such monitors, but in stead of paying extra for a 24 to 28 inch stand, the A.T.s give you a slender tower design that incorporates a proprietary labyrinth that synthesizes bass notes that no three-inch driver has a right to produce. The total excursion of its cone is only one millimeter, after all. And with no crossover, there is time and phase coherency throughout its range. David Maeshiba explained that the bass notes coming from the rear port were close enough in time to the midrange and treble notes (7ms comes to mind) that the mind hears it as being time coherent. I did note, however, a discontinuity in the quality of the music between the directly radiated notes coming from the driver and the synthesized bass notes emanating from the large rear-facing port at the bass of the tower. The midrange and treble were well focused, but the bass has warmth and resonance characteristic of a wood bodied musical instrument. Another term for this might be "cabinet induced coloration".

The audiophile in me had a hard time coming to grips with this discontinuity because at the same time I was equally enjoying listening to music through these speakers. A lyric from Leonard Cohen's "Love Calls You by Your Name" helped me resolve the situation. He wrote:

You stumble into this movie house then you climb, you climb into the frame.

As a film maker and videographer I did this all the time. And now, as an audiophile, I'm still guilty of this. I climb into the musical presentation seeking perfection and ferreting out flaws in the system. But if I sit back and let the music bathe me like water cascading over the falls, the AT is very pleasurable. My toe taps right along with the music. This brings me back to Bill's wife, who, not being an audiophile, simply bathed in the music coming from these speakers and loved what she heard. Another factor that may have led to her enjoyment was the smoothness of the upper treble. Women, in general, have better hearing than men, particularly in the uppermost frequencies and are quick to dismiss an irksome tweeter. While the treble sounded rolled off to my aging male ears, it actually measured surprisingly well. In fact, it was this curiosity about the high treble (as well as the bass) that led me to pull out my somewhat trusty Radio Shack analog SPL meter for a set of crude measurements taken from the listening position — a practice that David Maeshiba also prefers. This method incorporates the room response as well as the off-axis response which more closely represents what I was actually hearing than would an on-axis, anechoic measurement. Audio engineers, of course, think otherwise, but I'm more schooled in British Empiricism than electrical engineering.

Keep in mind the extremes of this meter's range are not terribly accurate. The range from 400 Hz to 8 kHz is exceptionally smooth and would probably test smooth to a much higher frequency with a better metering system. In the 100 Hz to 200 Hz range I typically have a room peak as shown, although this one is more moderate than most loudspeakers I've measured. The bass falls off in the mid and lower bass as you would expect, and in fact, with a 3-inch driver it is a wonder that there is any bass at all. In that regard it reminds me of the single driver Tekton Design speaker and begs for a subwoofer. (I'm told they are working on a subwoofer but it is not yet ready for production.)

Keep in mind the SPL chart is a measure of energy and does not correlate to the quality shift I heard in the bass that I mentioned above. It also does not reveal such shortcomings as the soft attack I heard on rim shots or even on cymbals.

Both of these traits lean the A.T. toward pleasurable, non-critical listening. Also missing from the chart is the very nice transparency due to the time and phase coherency and the absence of electronic crossover. I drove the A.T.s not only with my hot-rodded Manley Mahis, but also with my Plinius solid state muscle amp, very conservatively, I might add. The A.T.s gave one of the deepest soundstages I've heard with solid state, and the tonal characteristics of the speaker did not seem to shift as much as usually happens when you go from tubes to solid state, or vice versa. It works with both, as long as you don't over drive them. Obviously, with a 3-inch driver, this is not a speaker for head bangers, but I could easily play them at moderate levels.

Ergonomics and Aesthetics
With only a single small driver at the upper end of the front baffle, the rectangular tower has an elegant form that should work well in almost any décor unless the dark finish is a total mismatch. Optional veneers are available at an additional cost. A clear plastic cap is provided for protection during shipping and can be used when not listening and when small children are playing about. Still, the speaker and driver do not draw much attention to themselves. The finish of the cabinets, which are made in Mexico , is about par for what I see in the furniture world coming from abroad, and about what you would expect in this price range.

What bewildered me was the absence of spikes to anchor the speaker to the floor. David Maeshiba claims they are not necessary, but I experienced a small improvement in focus when I placed a pair of Symposium Acoustics shelves beneath them. On my wall to wall carpet with a soft pad beneath it, the speakers seemed tippy at first, but after a while, once the carpet compressed beneath their weight they seemed less vulnerable. They were even more stable when placed on the shelves and would probably have about the same stability on a hardwood floor. Being use to much heavier speakers, I probably would feel more secure with spikes and the focus would likely improve a bit as well. Anyone competent with an electric drill should easily be able to retro-fit them if they choose. At only 33 pounds each (17 percent below spec) with a center of gravity about at its midline, it is somewhat vulnerable to being knocked over by clumsy adults or rough-housing children.

Summary
I've heard precious few loudspeakers that can hold a soundstage was well as this one when walking about the room. Its sweet spot is as wide as your sofa which makes it great if you share your music with others. The single driver technology gives very good transparency, though its focus did not seem as good as my distant impression from CES earlier in the year. There is a reasonable impression of bass, but real bass lovers will yearn for a subwoofer or two. Had the focus been as good as the transparency, I could have loved this speaker a lot more. In fact, as I look back at my excitement over this loudspeaker at the CES show, I'm not entirely sure I got it right in my own room. But my time is up. If you get a chance, see if it works for you.

Specifications
Type: Fullrange single driver loudspeaker
Driver: 3-inch titanium cone
Internal Wiring: Solid silver wire 99.99% purity
Binding Posts: Gold-plated solid copper - (Cardas CCGGL)
Crossover/Filter: None
Nominal Impedance: 8 Ohms
Rated Power Input: 15 Watts
Maximum Power Input: 30 Watts
Dimensions: 43.25 x 6.25 x 9.75  (HxWxD in inches)
Net Weight: 40 lbs. each
Price: $2450

Company Information
One North Wacker Drive
Suite 4130
Chicago, Illinois 60606

Voice: (312) 948-4400
Fax: (312) 984-0146
E-mail: info@acoustictechnologiesllc.com
Website: www.acoustictechnologiesllc.com