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Positive Feedback ISSUE 19
may/june 2005


aerial acoustics

Model 6 loudspeakers

as reviewed by Jeff Parks






Aerial 7Bs in Bird's Eye Maple, coupled to the floor using OEM (optional) Sound Anchor stands.

Audio Research SP-15 preamplifier--modified by Richard Kern of Audiomod, an Audio Research VT-100MKIII amplifier with twin Genalex NOS KT88 matched quads or the equivalent Audio Research matched quads of Svetlanas 6550Cs, and M-150 monoblocks by Keith Heron.

VPI Aries w/JMW 10.5 arm-Benz Micro Ruby 2 H cartridge, a PS Audio Lambda II Special transport--modified by Richard Kern of Audiomod, and a Dodson 218 DAC.

Cardas Golden Reference interconnects both XLR & RCA, Cardas Golden Reference bi-wire speaker cables, Acoustic Zen MC-2 Silver and Audio Magic Clairvoyant S/PDIF digital cables, and PS Audio xStream Statement power cords.

Bybee Magic Bullets, a PS Audio P-500 power regenerator for source gear and preamplifier, Wally Tools, PS Audio Ultimate Outlet 20 amp high-current version for the amplifiers, a VPI SDS power regenerator for the Aries table, two Townshend Seismic Sink stands, a Townshend Seismic Sink for the Aries, a Bedini Dual Beam Ultra Clarifier, Shun Mook Diamond Acoustic resonators under preamplifier, a VPI 17F vacuum record cleaning machine, 9 Bright Star Big Rocks under all gear except for VPI Aries, Bright Star Little Rock 3s atop PS Audio Lambda II Special and Dodson 218, 9 Bright Star Little Rock 2s on top of all gear except for VPI Aries and Audio Research VT-100MKIII, 3 Lovan Sovereign sand filled amplifier stands, 9 RPG Skyline diffusers (back wall), 32 RPG Melfoam diffusing/absorbing panels (front and side walls), 4 Echo Buster Corner Busters, a set of 3 Argent Room Lens diffusers/tuners, 3 Sound Connections 15 amp duplex outlets, and one 15 amp dedicated line.

Being an audio reviewer can be tough. Let me cite an example. I recently spoke to a major manufacturer who stated, "I have no need for reviews or reviewers. In fact, I would prefer not to have them at all—reviews, that is." This manufacturer was extremely curt, bordering on rude, even after I told him that I used to own one of his products and loved it. The problem was simply that I was an audio reviewer. Talk about prejudice! This person did not know me, yet was treating me like some sort of lower life form. I was taken aback by his attitude. I feel that I am an honorable person. I believe in God and country, and even my profession as a middle school teacher leads most people to consider me honorable. (Just a couple of months ago, I received a Teacher of the Month award at my school, so I must be doing something right!) Nevertheless, I have to agree with him that many reviewers do a disservice to high-end audio by failing to devote sufficient time to products, or by publishing reviews that are either unjustly negative or unjustly positive. Maybe that is why it takes me so much time to write reviews. I like to have a component in my system for a long time, in order to really get to know it.

You would not believe some of the stories I have heard about audio reviewers who have not done their jobs properly. I know of one case in which a reviewer gave a product great praise, yet returned it to the manufacturer in unused condition. The manufacturer told me that it appeared that the product had never left the box! In another instance, a reviewer wrote about a product after having it in his system for less than 100 hours, when the product does not sound its best until well over 400 hours. (In case you were wondering, to the best of my knowledge, this has never happened at PFO.) Given situations like these, I can see the point of the manufacturer who has no use for reviews. That is why it is so important for reviewers to talk to manufacturers about their products, so that they can evaluate them in the best possible circumstances. I see this as no different than a customer calling a dealer to ask for help in optimizing the setup of a component they have purchased.

I am telling you all this to let you know that when I write a review, I take it very seriously. I know that high-end audio manufacturers put their hearts and souls into the products they design for our listening pleasure. One such manufacturer is Aerial Acoustics. Aerial' s lead designer, Michael Kelly, has been involved in the audio business in some way or another for four decades, so to say that he is an industry icon would be an understatement. Kelly is an engineer with a degree in physics. He also has an MBA from the Massachusetts Institute of Technology, which has been responsible for graduating some of the biggest names in high-end audio that the United States has to offer. Prior to graduating from MIT, Michael honed his skills at Analog Digital Systems (A/D/S), where he was Executive Vice President of Research, Design, and Manufacturing, and designed the drivers used in A/D/S speakers. He now applies his education and professional experience to everything he does at Aerial, where he designs all of the drivers for his loudspeakers, along with Dave Marshall and the Aerial design team. I have always been a fan of Michael's designs, going back to his days with A/D/S.

Back in October 2003, I bought a pair of Aerial Model 7Bs from Stereo Design in San Diego, a model high-end retailer with whom I have done business for the last 25 years. In the more than two years that I have owned the 7Bs, I have become an even bigger fan of Michael Kelly's work. Given my enthusiasm for his products, I felt that it was time for me to write about some Aerial speakers. With that in mind, I called Michael last September, and we discussed the possibility of my obtaining a review pair. Knowing that I already owned the Aerial 7Bs, he suggested that I start out with the Model 6.

The 6s arrived last October in great shape. Although they were not crated, they were shipped on a wooden pallet. The speakers were double-boxed in corrugated cardboard, with the sides, tops, and bottoms reinforced by quarter-inch sheets of hardboard that added rigidity to the boxes and protected the speakers from mild to moderate punctures. I found this to be a nice touch. After pulling the 6s from their boxes, I moved them around a bit in my heavily treated sound room (see the description in the margin of this article for further information). They ended up very near the positions of my 7Bs–that is, 42 inches from the back wall and 30 inches from the side walls. I toed them in so that the tweeters were pointing just outside my ears and tilted them slightly back (about five degrees). Despite their small size, moving them was quite a workout. Without stands, the 6s weigh a hefty sixty pounds each, probably because of their heavily braced cabinets, with 1-inch MDF construction for the front, side, and back walls and 2-inch MDF for the top and bottom panels. The stands add another three pounds to each speaker.

In my opinion, the stands are a must-buy. Without them, the 6s were not very stable on my heavily-carpeted floor, even using the supplied spikes. This is due to the small footprint of the speakers (39 x 7.25 x 12 inches). The stands couple the speakers to the floor, tightening the bass and offering the ability to tilt the speakers backward if the tweeters are not at the proper listening height. According to Aerial's national sales manager, John Quick, it is imperative to line up the tweeters with the listener, since this is how the speakers are voiced. Doing otherwise will not allow the 6s' true potential to be unleashed. Another reason to consider the stands is that if you were to bump into the speakers (or, God forbid, there's an earthquake, which happens often where I live in Southern California), they are likely to fall, and to take out whatever they hit along the way. Who would want to risk damaging the 6s' beautiful finish? Their book-matched cherry cabinetry is among the best in the industry, something my wife definitely noticed. She said, "Those are pretty. Are we going to keep them so that we can replace those ugly speakers in your home theater system?"

The Aerial 6s are built like brick shithouses. The cabinets are basically inert. The fit and finish of the cabinets, the weight of the speakers, and the gold-plated bi-wire speaker connections all announce that these are serious loudspeakers, not your everyday mini-monitors. Michael Kelly informed me that the 6s were designed with the goal of achieving most of the 7Bs' performance with smaller cabinets. Michael stressed that he wanted the 6s to give mini-monitor performance with respect to imaging and soundstaging while going down low enough in the bass to function by themselves in small to medium-sized rooms. In my 13 x 16-foot room, the Aerial 6s were in their element.

Other factors that add to the performance of the Aerial 6s include the quality of the parts and the design of the crossover. The Aerial 6 drivers are custom-built to Michael's specifications by Danish Sound Company (midrange drivers and woofers) and MB quart (tweeters). In addition to being custom designed by the Aerial design team, all bass and midrange drivers are treated with a proprietary coating that helps prevent cone breakup. Next, they are matched in pairs that perform within 1 percent of each other. Meticulous? Yes, but Aerial believes that this is necessary to get the performance they are looking for, which includes proper phase and time alignment. These procedures promote the excellent soundstaging, imaging, and clarity for which Aerial designs are known.

The 6s' crossovers are the work of Dave Marshall and his design team. Aerial takes crossovers very seriously, as they can make or break the performance of a loudspeaker. After researching a lot of different designs over the years, the Aerial team has settled on a 24-dB-per-octave Linkwitz-Riley type design. They chose the 24-dB slope because, in order for the drivers to be in phase, the only other choice would be a 6-dB slope, and according to Michael Kelly, with a 6-dB network, drivers reproduce frequencies at and above the crossover point. In other words, the woofer is reproducing frequencies at a 6-dB cutoff point while handing off those same frequencies to the midrange driver, which is rising at 6dB per octave. This means that both drivers are reproducing the same frequencies at the same time, which can introduce a lobbing effect at the crossover point. The same thing can happen between the midrange driver and the tweeter. By using a 24-dB slope, you operate the loudspeaker in the middle of its bandpass, thus promoting optimal performance while avoiding lobbing effects.

Aerial also uses the best crossover parts, including custom oxygen-free copper wire, polypropylene capacitors, and in the bass circuit, some very large air-core capacitors wound with custom wire. The fact that Aerial uses custom drivers built to exacting specs means that they can use fewer elements in the crossover. With a simpler crossover circuit, you hear less from the crossover and more from the speaker. Also, the savings in parts can be applied to other things, like the cabinets.

The Aerial 6s are front-ported. Placing the port in the front allows the user to place the loudspeaker closer to the back wall than is possible with rear-ported speakers. This can be a real advantage in a small room, where it may be necessary to place the loudspeaker near the wall. The placement of loudspeakers relative to the rear and side walls definitely affects how they sound, since their proximity to walls affects how they "load" the room. It not impossible to get great sound from rear-ported speakers (the 7Bs are rear-ported), but more time and care is needed to locate them.

Once I found the optimal locations for the Aerial 6s in my sound room, I let them play for over 100 hours before I did any serious listening. I did stop in for a quick listen from time to time, but knowing that the speakers needed time to mellow out and to integrate with my room, I didn't stay long. After 100-plus hours, the 6s were sounding pretty good, but I decided to give them more time, since they still did not have the bass extension or top-to-bottom cohesion that Mike Kelly and John Quick had led me to expect. I continued to allow them to burn in with my test CD, which contains both test tones and music. At 400-plus, I finally felt that the 6s were at their best. Although 400 hours seems like a long time to wait to hear the full potential of a product, I have found it to be the magic number, whether it applies to loudspeakers, amplifiers, preamplifiers, or other pieces of gear. As I go higher in the audio chain, it becomes easier to hear the differences in products as break-in time increases.

When I got down to serious listening with the Aerial 6s, the first words that came to my mind were "balance" and "harmony." Though they did not produce the seismic bass of my 7Bs, the 6s' bass is extended, natural, and precise. This may be due in part to their diminutive size, or to the fact that each speaker has only one bass driver. It is probably a combination of both of these factors, plus others. In my smallish sound room, I have often found that loudspeakers using multiple drivers can overdo things in the bass department, drowning out the midbass and midrange in the process. This was never a problem with the 6s.

An example of the 6s' coherence was their performance on the track "Fever," from Jeannie Bryson's CD Some Cats Know (Telarc CD-83391). Normally, Bryson is out in front of the string bass, as she should be, but the bass sometimes dominates her voice. This was not the case with the 6s—the bass was deep, clear, concise, and articulate, yet it allowed her voice to come through with the same precision that it does in her live performances. Listening to "Fever" with the 6s, I could clearly hear the bass player plucking his instrument while a percussionist played what sounds like a pair of kettle drums. Though the bass had great impact and and depth, it was never overdone, which allowed the midbass and midrange to emerge with uncanny clarity and gave me greater involvement with the music.

One of the greatest strengths of the Aerial 6s is their soundstaging and imaging. Never have I heard a pair of speakers disappear so well into the soundstage (The JM Labs Mini Utopias came close, but without the bass definition.) The 6s are truly gone. Take, for example, Roger Waters classic Amused to Death (Columbia CK 64426). The title track is an auditory treat, not to mention a good test of how well your speakers are set up. Waters used a technology called QSoundTM, which allowed him to play with the phase of the music to simulate the effect of surround sound. (For an in-depth discussion of this disc, go to Greg Weaver's PFO review at

"Amused to Death" begins with the voice of a television or radio talk show host in the deep left rear. This may not sound like a big deal, but with the 6s, the voice was almost dead-on with the plane in which I was sitting. That was freaky. It was like I had a rear-channel speaker, but I had none! At first, having voices coming from positions immediately adjacent to my sitting position startled me, but as the track continued, it helped me to enter into a realm of Roger Waters' creation. Next came the congas, which had an awesome presence. I could hear the sound alternating from drum to drum with uncanny precision, while hearing the inner resonance of each. The bass was deep, bordering on seismic, room filling, and all-encompassing, without bloat—it was perfect! The track ends with an English gentleman reciting some sort of monologue, again from the left rear, and again on the same plane in which I was sitting, followed by the sound of crickets. The crickets seemed to take up an entire third of the sound room, filling it up on all sides and falling short of the ceiling by about two feet. This gave me the illusion of setting on the screened back porch on the farm in St. Joseph, Missouri, that has been in my family for over 150 years. It is one thing for an audio system to give you the illusion of a musical performance, but entirely another thing for it to transport you across time and space to a place you always long to be. For me, that is audio nirvana!

The other day, when I was getting my daily caffeine fix at Starbucks™, some pretty cool jazz was being played over the speakers. The vocalist sounded very much like Billie Holiday before she ruined her voice with cigarettes and booze. Inquiring at the counter, the coffee technician (that's what they call themselves these days, at least where I live) guided me to the CD display where I found, and bought, the second disc by a singer named Madeleine Peyroux, entitled Careless Love (Rounder 11661-3192-2). Through the Aerial 6s, this recording sounded very realistic, again due to the excellent soundstaging, imaging, and—most importantly—layering of the performers across the soundstage. I assume this is a byproduct of the recording process, but it certainly demonstrated the 6s' ability to reproduce what it was on the disc. The track "Dance Me to the End of Love" showed off the 6s' uncanny ability to get out of the way of the music. Peyroux' raspy voice was located with pinpoint accuracy, just to the left of center stage and behind the plane of the speakers. Behind her was the drummer and the string bassist. All sounded very realistic, and very impressive, with each occupying their own space. Midway through the track is a piano solo, in which all of the notes had the proper attack and decay. There was no rolling off at the top, and micro and macrodynamics were all there, giving me the illusion that I had a grand piano in my small sound room and allowing me to forget that I was listening to a recreation of the original sonic event.

No matter what music I played, the Aerial 6s gave the illusion that my sound room was much bigger than it actually is. The sound extended well beyond the speakers, almost like the performers were outside of the room. Although, depending upon the CD, the music sometimes sounded a bit forward, I felt that this was more the result of choices made by the recording engineer rather than ones made by the designers of the speakers. It might also have been attributable to the rest of my equipment. It is the 6s' ability to disappear, and their lack of any boxy coloration, that makes them unique in their class. You know they're there, but where?

Complaints? None, really. Alright, I do have one gripe. With all that Aerial has to offer, you'd think that the owner's manual provided with the Aerial Model 6s (and the 7Bs, for that matter) would be a little more informative. It offers just the basic facts and the specs. Vandersteen manuals explain in detail how to place the speakers in your room. Aerial could do the same. When I quizzed Michael Kelly about this, he explained, "We do regret this, and we are in the process of correcting the problem." With the cost of high-end speakers these days, maybe it is better to allow the dealer to help you set them up, but it would be nice to hear the manufacturer's recommendations about placing their speakers in your room.

If you haven't already noticed, I liked these loudspeakers. Let me rephrase that—I loved them. I have owned speakers from JM Labs, Vandersteen, Kef, Meadowlark, Tannoy, and of course Aerial at one time or another, and while I have enjoyed and been impressed with all of them, none have struck me like the Aerial Model 6s. I have fallen hard. Why shouldn't I? The 6s have great bass, excellent top-to-bottom balance, and phenomenal mid to upper-end detail, yet they never sound harsh, and they disappear within the soundstage like a cat on the hunt. These are keepers! Jeff Parks

Model 6 loudspeakers
Retail: $3600 pair in black; $4000 in Natural Cherry, Rose Walnut, and Rosewood; $4400 for  Bird's Eye Maple.

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