Aural Acoustics Model B
Loudspeaker
A tale with two preamps and four amps.
Review By Rick Becker
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  Try as I may, some reviews take longer than others. In this case, it was a long and twisted road filled with numerous diversions and a lot of work. The story began almost a year ago at the New York show where the Aural Acoustics caught my eye and ear. It sounded very good and the technological emphasis on vibration absorption hooked my interest. But it would be another half year or more before a pair finally landed for review.

This is a young company and the design and testing of the shipping cartons delayed their progress. Spencer Clark, the designer and owner of Aural Acoustics also insisted that I review the Model B with a set of conrad-johnson gear, which had been used in the voicing of the loudspeaker. To complicate matters, c-j was just introducing new preamplifiers and power amps, so it made sense to wait until these became available and have me review them as well. Many reviewers would balk at such a request, arguing that to throw even two new components into a system would negate the reference. I heartily agree, but took on the challenge anyway, figuring that I would evaluate each component separately, and then in combination. Can you see the mountain rising before me? The trail upward became even steeper when the rare and exotic KR Kronzilla DX monoblocks arrived for a brief three-week stay. But often the more difficult the mountain, the more spectacular the view can be.

With the Manley Mahis
When I dropped the Model B straight into my reference system fresh out of the box, it only hinted at what I remembered from the New York show. The drivers required a substantial break-in, somewhere in the neighborhood of a hundred hours, which I accomplished with my video system while Linda was away on business. But even back in the big rig after break-in, it still did not equal my distant memory. The mids and highs were pretty good, but the bass suffered from excess emphasis and distortion and they did not reach very deep with my Manley Mahis. The tonal balance was bass heavy, but it wasn't a very tight or deep bass. I began to suspect why Spencer wanted me to use the c-j equipment.

With The KR DX Monoblocks
Thinking the bass needed more power; I swapped in the KR Kronzilla DX monoblocks that had dropped by for a quick review. With their 100 watts of single ended triode power, I though I might reach nirvana that way, but I soon learned there was no short cut to the top of the mountain. The bass was definitely tighter with the DX monoblocks, but the tonal balance was knocked even further out of balance with the bass even more prominent than with the Mahis. Of course, this also explains why the KR DX monoblocks and the Mahis work so well with my reference Kharma loudspeakers, which benefit from the strong bass.

With The conrad-johnson MV60-SE
At this point I decided to get with Spencer's program and try the conrad-johnson MV60-SE that had come along with the new CT-6 preamplifier. Ahhhh! Now I see why he insisted I use the c-j equipment. The bass was de-emphasized, relative to the Mahi and KR, resulting in better tonal balance. The bass and mids were now much more compatible. The terrific resolution of the MV60-SE also benefited the Model B, achieving even better midrange and treble focus than the Kharma 2.2, just as the Escalante Design Pinyons and Von Schweikert VR-4jr had done earlier. (But stay tuned for my upcoming review of the new Kharma 2.2c). On the flip side of the coin, the MV60-SE left the bass of the Kharmas sounding less prominent, in spite of having greater power than the Mahi. On the positive side, the resolution of inner detail across the board rose up a significant notch above the less expensive Mahis. It was easy to see why the MV60-SE has been so highly acclaimed, but it wasn't an optimal match with the Kharmas — at least at this point in the game.

While the CT-6 and the MV60-SE drove the Model B loudspeakers very well in my large room, there was evidence of some shortcomings. The tonal balance was still tipped upward in the mid-bass, though it was now in much better focus and more seamlessly connected to the midrange. This is good news for those who equate bass response with chocolate, I suppose, but there were some other issues. As the bass fell off from about 40Hz, it started to sound pretty ugly. I suspect part of the problem is the smallish 7" woofer. Did I say "smallish"? The nominal 7" driver, which has only six inches of exposed cone diameter, is very small for a driver that put out this much bass in such a large listening room!

Furthermore, the front of the Model B was 65" in front of the wall behind it and there were no corners anywhere near it to reinforce the bass. This performance was quite admirable and the shortcomings forgivable, given these circumstances. The port on the Model B is positioned on the front of the loudspeaker to facilitate placement of these loudspeakers closer to the front wall, which will be a more typical requirement in many homes. Also, most listening rooms for loudspeakers in this price range will be considerably smaller than mine (6000 cubic feet with wide open passageways to adjacent rooms). In a smaller room, I expect you will have a much more musical roll-off in the bass than I had with this amplifier. Nonetheless, you can expect a strong bass. The quality of that bass will depend on the particular amplifier you will use, which brings me around to the last amplifier in my deck of cards.

With the Plinius SA-100
Back in the 1990's I picked up a used Plinius SA-100 Mk III to replace my old Counterpoint amplifier that suffered terminal melt down. I had used the Plinius for many years, first with an EAR 834L tube line stage and subsequently with the CAT SL1 Sig. III that I use to this day. I liked the combination of a tube preamplifier with a solid-state power amp. The Plinius was especially nice because I could run it cool in Class AB, and do my serious listening in Class A with the flip of a switch. This feature also allowed me to keep it fired up constantly, which had definite sonic benefits. It also helped to heat the room during cold winter listening sessions. A couple of attempts to sell it over the years didn't bring sufficient offers so I've been hanging on to it as a reviewer's tool. Good thing! I placed the Plinius on the amp stand with a set of Boston Audio Design TuneBlocks under it and let it warm up for a day. It takes several days for it to fully settle in after sitting for a long time. I left the CT-6 in the system, knowing that a good tube preamp helps the Plinius a lot. I didn't have great expectations for this combination, but I figured I would learn something about the ability of the Model B to produce deep bass.

With the CT-6 preamp and the Plinius amplifier, it was evident from the start that this was a special combination. The CT-6 was sending the Plinius the cleanest, most transparent signal it had ever seen and it transformed the amp from a virtual boat anchor into a respectable muscle amp. The effect of this combination on the Model B was very impressive at first. The mid-bass not only tightened up dramatically, but as the bass rolled off, it did so musically, not distracting the listener from the core of the music in the midrange. The tonal balance was still strong in the bass, but there was continuity with the midrange by virtue of the seamless degree of focus that stretched from the depths of the bass through the treble.

If the music was bass heavy, as with modern rock music or rap, the prominent bass stood out and could be objectionable to people who don't like that music to begin with. (That's a joke on the British side of the pond). In concert hall recordings, the bass emphasis contributed to the "you are there" experience with the explosive dynamics of classical music and the ambient hall reverberations. Looking upstream past the Plinius, it was easy to understand the contribution of the CT-6 to the black background, the fast attack and decay, and the excellent focus. And of course it was the Model B that had the ability to manifest those attributes. The Plinius SA-100 Mk III has been superseded by two generations but apparently there is more thunder in the old girl than I ever knew she had. Still, it makes me wonder how good the Model B might be with a more contemporary solid state design capable of dealing with its moderate 87dB/W/m sensitivity.

The payoff of time alignment and phase coherency was evident in the superb focus that only rarely became irritable — and then only because of the source material. With my favorite "bad" CDs (Dylan's Real Live and Hendricks' Live at Winterland) the lyrics were readily discernable and the focus and transparency of the system allowed me to revel in the creative use of distortions by the musicians. With the tight control of the bass, the pace and rhythm of the music caused almost endless toe tapping, revealing my subconscious delight. And that delight, more than sonic perfection, is the greatest reward for me.

The Model B is a wide dispersion design and in walking around the room the music did not lose focus, although the tonality would shift somewhat as I walked through resonant room nodes. The soundstage was also fairly well preserved one seat immediately to the left and right of the listening chair. Tonality shifted when standing up from the listening position, as often happens, but changing the volume did not produce any major shifts in the music, other than the rolling off of the bass a little and the treble more so when the music was lowered into the 70dB range. This is a normal response of human hearing and the reason why all those mid-fi receivers we listened to in the old days had a "loudness" control.

The Model B does not suddenly "come alive" at any point when the volume is slowly raised as some loudspeakers do — it is always alive! There seemed to be a cap on how loud it would play, however, starting to compress when the peaks reached the 100dB level. Keep in mind the sensitivity of the loudspeaker, the size of the woofer, the large volume of my room and the "mere" 100 'Class A' watts of the Plinius. It was probably asking too much of the Model B to play any louder. For me, this was not a problem as I typically listen with the SPL needle dancing in the 85dB to 90dB range. On late nights when Linda retired early, even at very low levels in the 65dB range, the inner detail and luminance of the midrange made listening to music a pleasure. At such low levels, the band sounded like it was playing on the roof of a loft on the next block, but it was still enjoyable. This can be an important feature for keeping peace in the family.

The soundstage with the Model B was recessed behind the loudspeakers, placing the singer with his nose to the outside glass of my front window. It was also as wide as any other components have been able to produce in my room, but on Hearts of Space on National Public Radio the music extended even further — several galaxies to the left and right (read this as poetic, but not cute). Even more amazing to me, it extended out into the room to the listening position, a phenomenon that is extremely rare with my wide room configuration). With more typical music, the soundstage itself was very deep extending out into the yard and instruments and back-up singers were firmly planted in their positions. Moreover, the furthest reaches of the soundstage were very well illuminated due to the excellent focus of the Model B. The three female voices of the Wilson Phillips group were easily discernable in spite of the very tight weave of their harmony. Recordings made in a large space, or with added reverberation, were positively holographic. A recording of didgeridoo music by the master David Hudson convinced me that the aboriginal instrument is the direct predecessor of the earliest Moog synthesizers. Even those recordings of more familiar music made in more intimate settings had an airy, three-dimensionality that is highly prized.

Much attention has been paid to absorbing vibrations behind the drivers inside the three individual cavities of the Model B. At the New York show, I was able to see inside one of the cabinets, and there appeared to be small amounts of sound absorbing materials strategically applied to the walls. This is part of their PureSound Phase Array which is explained in more detail on their website. There was still some minimal vibration to be felt on the outer walls of the loudspeaker, but the fact that they achieved such a high degree of focus and such stable imagery, suggests that the job is getting done without the use of ultra-thick cabinet walls and a labyrinth of internal baffles. The soundstage was placed well behind the loudspeakers and the loudspeakers themselves disappeared almost as completely as the much more expensive Kharmas. The 9" wide x 13" deep cross section of the tower certainly contributes to this effect, being about the footprint of a typical small monitor, though the base flares out slightly at the floor. The small footprint also means it will not visually overpower more modest size rooms — another big plus, which leads to the next area of importance.

Aesthetics & Functional Design
The unique waterfall styling of the front of the Model B is the obvious major design element. With the grilles in place it is very handsome, giving the loudspeaker an identity among the multitude of floor standing towers of this general size. Even to the uninitiated, this appears as a somewhat special loudspeaker. I requested the cherry finish because cherry fits very well with my decor. I was hoping it would be of the same outstanding character and quality of the Coincident loudspeakers in our video rig, but it was not. It falls on the dark side of brown country cherry and has a rather flat, lifeless finish without much depth in it. At first this was a disappointment to me, kind of like a blind date that wasn't quite as attractive as I imagined.

Taking the three individual grilles off also revealed a rather gangly façade as I discovered the woofer is mounted on yet a fourth vertical plane. The Sonotex dome tweeter with its copper ring and large felt covered flange, and the brassy colored woven carbon graphite and Kevlar midrange further contributed to the initial feeling of awkwardness of the design. She was definitely not the first girl chosen for the cheerleading squad, but she was on the squad nonetheless, and for very significant reasons. Let me tell you why.

In the course of living with the Model B, sans grilles, the many sonic virtues of the loudspeaker emerged, and gaining familiarity with the visual styling ameliorated the visual shortcomings. Furthermore, many listeners may actually prefer to leave the grilles on. In fact, they were designed to be used that way... but you know how audiophiles are. I did most of my listening with the grilles off. Installing the grilles while listening to New Age music shrank the soundscape from galactic to merely very good proportions and the soundscape became more recessed. They soften the sound ever so slightly, and they dress the speaker up for when company comes to visit. On more than one occasion, however, I discovered that I had left the grilles on without knowing it, and didn't notice the audible difference while listening. This happened to me both listening in the dark and in broad daylight! The cherry finish, while not spectacular, is very easy to live with, blending in with both country and more formal, traditional settings. By not calling attention to the loudspeaker visually, I largely ignored it and bathed in the timbre and tonal coloration of the music.

You also have the option of light natural maple, which fits in very well with light, contemporary décor. And of course there is the option of black ash, which can be stunning in contemporary settings, and even fit in well in traditional settings, given the conservative styling of the tower. Both the natural maple and the black will command your visual attention more than the cherry, however, not only because they are more striking colors, but because the finish appears to be of the high quality that is typical of these finishes. The front of the loudspeaker is black, as is the grill cloth. Leave the grilles on and the visual shortcomings disappear, leaving you with a loudspeaker that is very appropriate for all but those who wish their loudspeakers to scream, "Look at me!" With such a distinctive façade, the Aural Acoustics nameplate on the lower grille cloth might better be positioned on the backside of the loudspeaker for those who are curious. Most people don't want to know, and will be impressed by the design of a loudspeaker, caring less about who the manufacturer might be. Your audiophile friends will ask, giving you an invitation to talk about them.

The tapered black base of the loudspeaker is a fully isolated chamber, which houses the crossover and also protects the wood veneer from the ravages of the vacuum cleaner. Unfortunately, the positioning of the spikes does not take full advantage of the wider stance offered by the base; they could be mounted closer to the corners for even greater stability. The vulnerability from being bumped is greater from side to side than from front to back. While it is less vulnerable than many other loudspeakers I've bumped into, it could be improved a bit with little effort. The weight of each loudspeaker is sixty pounds and it is reasonably easy for one person to handle on occasion since the center of gravity falls close to the body. The speaker cable binding posts are knurled for finger tightening and also have a hex grip for the use of a binding post tool. They would be easier to tighten by hand if they were spaced further apart, however. There is only one set of posts so you will only need one set of speaker cables which will either save you some money, or let you buy a more premium set.

Thinking Inside the Box
As I said above, the anti-resonant AccuRange technology of the speaker really intrigued me. Not only is the crossover mounted below the loudspeaker in its own compartment, but is also mounted on an anti-resonant platform and anti-resonance glue is used to bind the elements to this base. Expensive film/foil capacitors give a very low noise floor and present an easy load to drive. Everything is hand wired and silver soldered.

The drivers have high power handling capability and very high bandwidth, both of which are necessary for the phase and time coherent first order crossover design.

Much attention is paid to dissipating the back wave of the drivers resulting in higher levels of detail and a lower noise floor, which in turn yields a higher perceived dynamic range. The drivers are mounted on a floating anti-resonance baffle with bituminous felt, although from the outside, they seem to be firmly mounted on the solid front baffle. Rapping my knuckles up and down the side of the loudspeaker I could clearly differentiate the individual chambers for the three drivers with the large bass chamber being the most resonant, of course, and the tweeter area being almost as solid as rock. Spencer tells me that the loudspeaker is not designed for ultimate output, particularly in the bass, but rather, the emphasis was placed on optimal decay response and overall accuracy. He also mentioned that the film/foil capacitors take a long time to break in — like about 300 hours. With all the component swapping entailed in a review such as this, it is difficult to keep track of the play time. I certainly passed the hundred hour mark before critical listening, which was necessary for the drivers to break in, but testing with the various amplifiers took place in a broad window that began at about 100 hours and was interrupted by the Montreal audio show, the writing of my Montreal show report and the International Home Furnishings Show. I did notice an improvement in the inner detail and particularly the bass response as time went on, so a bit of uncertainty clouded my earlier findings with the various amplifiers.

Check, Double Check
Rather than submit the review to meet the deadline, I ran the Model Bs continuously for another five days straight to be certain I had completed the 300-hour break-in time that Spencer suggested was needed for the film/foil capacitors in the crossovers. I then reconnected most of the various combinations of preamplifiers, power amplifiers and ran them with both loudspeakers, leaving the combination of CAT preamplifier and Mahi monoblocks out of the equation. While this exercise may seem a bit obsessive, I'm glad I did it as some new findings emerged, and I am confident with the results.

The bass became better balanced with the midrange and tweeter. It not only went deeper, but it was more tuneful. It still did not go quite as deep as the Kharmas, and it would occasionally protest the demands of loud output in my large room — usually in the neighborhood of 100dB or more. Within these limits, however, it was very enjoyable. And within these limits you will preserve your hearing longer.

Overall, the frequency response was equally enjoyable, but it was not as smooth as the Kharmas. The soundscape was further back behind the loudspeakers than with the Kharmas, as I said, but the quality of the soundscape of the Model B was superior.

The music floated more delicately and gracefully in air and was more holographic. The Model B was more transparent, and the transparency extended to the back of the soundstage — a distance that was also further than the Kharmas could reproduce. These characteristics seem to be precisely the stated goal of the AccuRange technology.

The conrad-johnson MV60SE amplifier also performed better with both the Model B and the Kharmas than I had previously mentioned, so perhaps it too needed more break-in time. While it did not give quite as deep and controlled bass response with either loudspeaker as did the Plinius, it was smoother, more grain free, more transparent and more holographic than the Plinius. On the flip side the Plinius would play louder and had better control of the bass. The pace and rhythm seemed a little quicker with the Plinius. I wouldn't hesitate to recommend trying the Model B with a good solid state amplifier of sufficient power, even though my personal preference might be for a tube amplifier. With the right amplifier, the Model B should be outstanding with either tube or solid state.

Many audiophiles, perhaps more those who are new to the hobby, fear the consequences of a loudspeaker being so "ruthlessly revealing" that they are forced to upgrade other components in their system faster than their finances or their comfort level might allow. The Model B gave lots of resolution with whatever amplifier I used, and each combination was enjoyable despite whatever minor shortcomings I heard, with the exception of the Mahis, which probably would have fared better if I had thought to double the wattage by switching it from triode to ultralinear mode. The arrival of two new review products, one for the analog front end and one for the digital, showed me that the Model B was capable of even greater musicality than I had experienced during most of the review process. I heard no evidence that adding the Model B to a rig would be degrading to the enjoyment of music. Its performance just kept getting better and better with each additional improvement to other areas of the system. It has a tuneful and somewhat prominent bass, in keeping with the listening preference of the North American market, but it also delivers a very refined sound for serious music lovers. It is not a loudspeaker for head-bangers.

The in-room frequency response graph presented here was taken at the listening position with a basic Radio Shack SPL meter and should not be confused with a more accurate graph made with more sophisticated equipment in an anechoic chamber. The frequency extremes are known to be inaccurate, and the measurements include the room interactions of the listening room. Furthermore, Spencer tells me the loudspeaker measures smoother with the grilles in place. Since I preferred the sound of the Model B without the grilles, this is the way I measured it. The graph corroborates my impression of the strong bass, but notice that it is strong over a wide range, not just in a single narrow band. This suggests a very tuneful bass region and indeed it was. The slight peak at about 80 Hz appears on most of my loudspeaker measurements, indicating that it is most likely a room resonance and probably a floor bounce.

Model B And The VR4-jr
Those familiar with the body of my review work will want to know how I think the Model B compares with the Von Schweikert VR4-jr. This is a tough call, with my JR review being over a year old. One major factor may well be the amplifier you intend to use. The JR performs best when it is bi-wired or even more optimally, bi-amplified, which will tip the overall cost balance considerably. I didn't feel like I had quite the optimum amplifier for the JR at the time, although I certainly tried a variety of different combinations. The JR achieves a similar holographic soundscape, albeit with the use of a second, rear-firing tweeter that may have some effect on phase and focus. With the right amplifier, the JR will play louder should you wish to destroy your hearing. Both loudspeakers will easily break your lease or spoil your marriage if you don't use them judiciously. The JR may go slightly deeper in the bass, but the Model B is probably more tuneful down there. Both loudspeakers had a similarly prominent bass response. The JR should be a lot easier to locate for audition, but you are unlikely to find these loudspeakers side by side at any shop. It kind of comes down to a David and Goliath situation, and you could certainly tip the balance by improper positioning of either loudspeaker, or selling your system short in some other area. The Model B is worthy of much more expensive components than it is likely to be paired with, but I pretty much said the same thing about the VR. I suspect the Model B would come out slightly ahead in transparency, focus and tonal color in a side-by-side comparison. But certainly, neither loudspeaker is a loser.

Summary
The Model B is a very high resolution; wide dispersion loudspeaker that throws a huge soundscape that is both recessed and very deep. It reveals extraordinary inner detail, micro-dynamics and tonal color. The music is airy, exceptionally transparent and effortless. However, it needs an amplifier with sufficient power to deal with its moderate sensitivity and capacity for wide dynamic range. Feed it with high quality components upstream and surround it with a properly tuned listening room and you will have a moderately priced world-class system to which all but the most obsessed could listen endlessly. The Model B is an outstanding first effort from Aural Acoustics. There's no need to wait for an improved "Model C". They've done their homework on this one. Very highly recommended, indeed.

Specifications
Type: Full range, floorstanding loudspeaker

Tweeter: Sonotex silk soft dome with Hexadym patented magnetic structure.

Midrange: Four inch driver with hand woven blend of carbon fiber and Kevlar cone

Woofer: Seven inch treated paper bass driver with Kapton voice coil former

Frequency Response: 33Hz to 25kHz

Impedance: 8 Ohms nominal / 4 Ohms minimum

Sensitivity: 87dB/W/m

Recommended Power: 35 Watts minimum

Features: AccuRange technology to dampen and absorb rear wave response, time and phase alignment for both drivers and crossover. Isolated free-floating baffles plus optimized driver chambers.

Real Wood Finishes: Black Ash, Cherry & Maple

Weight: 120 Pounds per Pair

Dimensions: 10.25 X 15.25 x 41.5 (WxDxH in inches)

Price: $4,500 per pair

Company Information
Aural Acoustics

Voice: (516) 626-2920
Fax: (516) 626-1138
E-mail: info@auralacoustics.com
Website: www.auralacoustics.com