Floor Loudspeaker Reviews

"It's difficult to make a loudspeaker that's room-proof," said Tom Norton, as we were discussing the Snell Acoustic Corporation's new Type B, four-way, 6-driver, full-range dynamic loudspeaker system introduced at the June 1991 Chicago Consumer Electronic Show. He and I were trying to make sense of conflicting listening reports about the Type B gathered from the magazine's writers over the preceding five months. What could have caused the wide variance in opinion? Might it be the result of the speaker's sensitivity to different rooms?

The Type B is the most innovative Snell loudspeaker to come along in years. Kevin Voecks, the company's main designer, used two active acoustic-suspension woofers positioned at different heights from the floor to reduce interaction effects and avoid exciting room nodes. The front woofer operates up to 275Hz. The rear 10" woofer functions as a subwoofer, being driven with the front woofer up to 40Hz. The rear "subwoofer's" crossover is configured to make the driver operate over an extremely narrow range (about 25Hz), so that, in effect, it behaves like the port of a vented system. Ironically, it is the Type B's bass response that has become the focus of review criticism. John Atkinson has speculated that the narrow response bandwidth of the rear subwoofer may be to blame.

Two veteran audio reviewers, Peter W. Mitchell and Robert Harley, came to diametrically opposed positions on this product. PWM based his enthusiastic verdict upon listening sessions at CES, spending hours auditioning the Type Bs using recordings he had made. His conclusions were as positive as I have ever read from him: "I know of no more accurate, transparent, or musically satisfying dynamic speaker at any price" (Vol.14 No.9, September 1991, p.51).

Furthermore, he had followed the Type B through its prototype stages at earlier CESes, in different environments, using similar source material, so this report was the equivalent of a very educated review. Earlier models were bigger (refrigerator-sized) and produced very powerful bass down to 16Hz. He was most impressed by the final production version, which he auditioned in June 1991 at the Chicago CES. Peter found that "The speaker is remarkable for its octave-to-octave balance, authentic timbre, spacious soundstaging, well-resolved detail, broad listening window, and freedom from both coloration and exaggeration...if I hadn't just purchased a pair of ATC SCM50 As, I would be strongly tempted to buy the Snell B" (Vol.14 No.9, p.51). PM suggested that the $5980/pair Type A/III Improved, the company's flagship loudspeaker system, had been dethroned by a system some $1800 cheaper. Finally, it seemed that we might have a Class A dynamic loudspeaker system in our "Recommended Components" costing under $5000. Or do we?

Stop the Music
Robert Harley disagreed vigorously with PWM in his full-length review (Vol.14 No.12), finding that he could not recommend the Type B. All his listening tests were carried out in a moderate sized, IEC-configured listening room in his Albuquerque, NM home. While praising the Snell's "excellent LF extension, smooth treble, high power handling and excellent dynamics," Harley criticized the Type B's "Achilles' Heel...its overbearing bass...[which] seemed sluggish and fat." In particular, kickdrum recordings in pop and rock "excited" a particular bass frequency that might not be noticed if one listened only to classical music. This bass peak colored the rest of the Type B's range in RH's listening sessions. In his room, the Type Bs played with a lack of transparency and were unable to create an impression of depth and image space. RH was unable to ignore or "listen around" these colorations. It's not surprising that he reported that the Type Bs refused to "disappear" into the listening room.

Voecks responded to the review with a lengthy "Manufacturer's Comment" in the same issue. He noted that the high output impedance of RH's VTL amplifiers (KV claimed 2.5 ohms, but the magazine measured only 1 ohm) could induce a 3dB response rise, centered around 30Hz, causing the Type B to "ring" at low frequencies, and prevent the speaker's "filter network from operating at its intended frequency and slope." Voecks also commented that RH's listening position might not allow him to hear the smoothest possible low-frequency response. Voecks went on to argue that the combination of high-output–impedance amplifier plus listening position could elevate the 30Hz response by 10dB; JA's calculations, using a figure of 1 ohm for the VTL's output impedance, suggests a milder 1.3dB boost. What's the reader to think?

A Gathering of Eagles
To further complicate things, the Snell Type Bs had been auditioned informally by most of the Stereophile reviewing staff. In late July, the magazine's contributing editors assembled in Santa Fe to attend the 1991 Stereophile Writers' Conference. The same Type Bs that would later go to RH had just arrived for review; TJN and I set them up in the Stereophile listening room. Listening was conducted in two two-hour sessions using either a Krell KSA-250 or a Threshold S/550e power amplifier. The group reacted negatively (they also criticized JA's Wilson Audio WATT/Puppy system, so the Snell was "in good company"). A lower-midrange "thickness" seemed to color the Type B's sound. I certainly heard this quality as I sat leaning against the listening room's rear wall. Even JGH heard a "nasality" in the midrange that was later picked up independently by RH (who did not participate in the July listening).

Can placement position explain it all?
Kevin Voecks visited Santa Fe the following month, and found that the Type Bs and the listening positions were too close to the room boundaries. Referring to TJN's diagram of the Stereophile listening room—see diagram—the Type Bs originally had been placed exactly where the loudspeakers are shown in the diagram, close to the Tube Traps (next to one of the extremely thick exterior walls found in Santa Fe buildings); the listener position was next to the rear-wall, 8" by 6" RPG Diffusor panels. Kevin moved the speakers and chairs several feet toward room center, and reported to me that much of the "midrange heaviness" disappeared.

Proper placement in a room is an important part of obtaining the best performance from a large speaker system. Correct positioning in an acoustical space can bring out a loudspeaker's transparency, imaging, and its ability to disappear, while the same system can sound mediocre in another acoustical setting. Anyone planning a sizeable investment in a loudspeaker system should audition the system at home and get the dealer's advice about optimal placement before deciding that the loudspeakers won't work. Hopefully, all this can be done before signing the check!

Reading all these reports, it's understandable that a reader would have trouble deciding if the Snell Type B is sensitive to room placement or just a flawed loudspeaker design. JA had the same question (Vol.14 No.12), wondering if our staff's divergent opinions might indicate a mismatch between moderate-sized rooms and the Type B's bass alignment. He suggested that I use my very large listening room to conduct a "Follow-Up" on the Snell Type B, examining its performance in a space that might favor its powerful low-frequency extension. I could also serve as a bridge: I'd heard the same Type B setup at the Chicago CES reported by PWM, and had been present at the Santa Fe listening sessions with the same pair of Type Bs reviewed by RH. (Unfortunately, I didn't hear them in his listening room.)

Listening setup
My listening room is considerably bigger than Stereophile's, RH's, and the June CES hotel listening rooms. It has dimensional ratios quite different from RH's room, and provides another type of room-mode distribution—my room is effectively much longer and narrower. Its true space occupies the entire first floor of my house, and is divided by a partial wall into a kitchen and a living room. The loudspeakers sit at one end of the living room, a 13' wide by 27' long space with a semi-cathedral ceiling 12' high at its peak. The side wall facing the outside of the house arches over to meet the other long wall, which rises vertically to the room's full 12' height.

Unlike the thick, immovable walls in the Santa Fe listening room, my house is constructed with New York Sheetrock, a building material with considerable give. The room's outer wall has a three-section, 6' by 10' bay window. The long, opposite inner wall has a series of equipment shelves, a fireplace (the brick is completely covered by sheetrock, which removed the room's previous flutter echo), and a large, built-in TV cabinet. These three areas are divided by decorative curved dowels that reach from ceiling to floor and further disperse sound. The short wall that serves as the back reflecting surface for the speakers has three large framed watercolors, but these are placed well above the speakers.

The room has a moderate amount of upholstery, including a 10' sectional sofa, an overstuffed reading chair, four small stuffed chairs, and two area rugs. One rug is a Baktiary Persian, 10.5' by 12.5', and the second is a circular area rug, 6' in diameter, that lies just in front of the loudspeakers. The three bay-window glass panels have lavolier blinds that are dropped into place during reviewing sessions.

The living room's space is effectively doubled by a connection with the kitchen. A large 10' by 8' opening to the kitchen provides access to an identical 13' by 26' room with 8' ceilings. This means that the sound can travel 52' from one back wall to the other! One of the long walls has a large open area for a stairway that goes both upstairs and downstairs.

JA visited during a trip to the 1991 AES meetings, and found this listening space very different from other Stereophile reviewers' rooms. For example, it would be difficult to follow Kevin Voecks's placement recommendations (one-third out from the rear wall), for it is hard to estimate where the "actual" one-third point might be. Adding the stairway and kitchen space, there must be over 5400ft³ of space. This is the sort of open quality found in New York City SoHo lofts; it can very much work against a small speaker. On the other hand, these large dimensions might benefit a loudspeaker like the Type B that had been developed using anechoic test procedures.

Detailed room setup instructions were not included with the Type Bs sent for review. As with any installation, only listening would reveal the speakers' optimal room position relative to distance from side and rear walls and how the speakers should be rotated vis è vis the listener. Should the grilles directly face the listener or be toed-in? As Harley explained, the drivers are placed along what RH described as a "sheared-off" corner of one of the speaker's long dimensions. Most listening in Santa Fe was done with these grilles turned in, so the loudspeaker's back panel was parallel to the wall and perpendicular to a line running from the listener to the back wall.

Kevin Voecks indicated via phone that the Type Bs were meant to be used out in the room, far from the back wall. (This is very different from Snell's <Type A/IIIs, designed by the late Peter Snell to hug the wall and not intrude into the room space; they depend on boundary effects to generate deep bass.) For most situations, the Type B grilles are meant to be aimed at the listener, or even aimed down the full length of the room.

RH, in his review, stated that the speakers were toed-in so that he was on-axis, giving "the best balance between solid center imaging and a wide soundstage." John Herron, Director of Sales and Manufacturing at Snell Acoustics, finds that a totally "open" stance (grille pointed down the long axis of the room) yields the widest, most spacious soundstage. Other listeners might face the Type Bs inward at 45° to a line running from the back wall to the listener to minimize side wall reflections. For my situation, however, Voecks recommended I point the grilles directly at my listening position. I agreed; I found that the Type Bs imaged best if the grille cloths faced directly at me. This meant that a corner of the loudspeaker enclosure was pointed at the back wall, rotating the rear subwoofers so they faced inward toward a center point between the speakers. They were thus directed away from the room corners, which could reinforce bass response.

Snell Acoustics provided me with copies of the CARA and LEO room analysis computer programs. These programs analyze room resonance mode distribution and suggest speaker/listener locations for each dimension of the listening room that minimizes bass nodes. Following one of LEO's suggestions for a "better" location ("best" could not be easily estimated), the Type Bs were positioned with the rear-facing corner approximately 24" from the wall, and the front panel about 45" from the rear and 36" from each side wall. The speakers were toed-in slightly and were 84" apart. The seated position was 18' away from a center line between the speakers, and the seat placed my ears about 34" off the floor (about the level of the Type B's upper-midrange driver).

Like RH, I had to move my Muse Model 18 subwoofer out of the listening room for any serious auditioning of the Type Bs. I had discovered that the Model 18's 25" height scrambles the Type B's ability to generate a central image. Of course, the Type B has more than enough bass, so one would probably not think of augmenting its response! In addition, I adjusted the tweeter-level controls between 12 and 3 o'clock, and swept the loudspeakers with a Heathkit sinewave generator before I began to listen to music. Standing at the equipment shelf, I heard the bass increase markedly as I swept the frequency down past 42Hz, very near the crossover point between woofer and subwoofer. Voecks's design, and measurements carried out at the National Research Council in Canada, showed that both drivers should be lower in output at this frequency, not boosted.

I left the sinewave generator playing at 42Hz and walked around my room. Sure enough, there were great differences in perceived amplitude, depending upon my position. Moving over to my favorite listening position, some 18' away from the front of the loudspeakers (I did mention that my listening room is large and unconventional, didn't I?), I found that the 42Hz peak had gone. I had someone else move the dial on the sinewave generator, and I could hear an even rolloff as the frequency moved down to 20Hz. The peak at 42Hz was a speaker-room interaction activated by the Type B's powerful bass response (but not so much by another bass wizard, the Muse Model 18; see below). I suppose I was becoming more convinced that the Type B, like other loudspeakers, could not be "room-proof." The room wouldn't "go away," but would always demonstrate nodes in positions where bass would be greatly emphasized. Fortunately, my listening position did not line up with such a node. But how would it sound on music?

Listening impressions
The Type B's appearance very much impressed me. The fit and finish of these black loudspeakers (the speaker is available in both black and walnut veneers) and their unusual geometry make them easily the most beautiful loudspeakers I've had in my listening room. Despite their size, the effect of flattening one of the long corners reduces their volume and creates a sense of visual space around them. Other tall loudspeakers, such as the Fourier One and the Snell Type C/IVs, or shallow but wide panel speakers such as the Quad ESL-63 USA Monitor/Gradient SW-63 subwoofer combination, seem to take up too much space, crowding together the furniture and objects in the room. The Type Bs complement my living room's contemporary decor. It was very pleasant to use them as my primary loudspeaker for several months.

The Type Bs reviewed for this "Follow-Up" were the third pair I had auditioned, the first having been heard in Chicago, the second at the Writers' Conference. RH provided an excellent description of their construction, features, and design in his Vol.14 No.12 review.

Music was selected to replicate RH's finding: Would the Type Bs do well with classical music, but have more difficulty with pop/rock kickdrum? I pulled out my favorite classical recordings, including solo piano works such as Glenn Gould's fabulous rendition of Bach's Goldberg Variations (Sony Masterworks IM 37779). I also used another current favorite, Leopold Stokowski conducting the Chicago Symphony in Shostakovitch's Symphony 6 (LP, RCA Red Seal LSC-3133). For kickdrum, I turned to one of JA's favorites, Jeff Beck and Terry Bozzio's "Behind the Veil" (from Jeff Beck's Guitar Shop, Epic EK 44313), as well as Richard Thompson's "I Misunderstood," from his great new album, Rumor and Sigh (Capitol CDP 7 957132).

The Type B had a definite emphasis in the bass, just as RH mentioned. I heard the kickdrum take a more powerful role in the music, this apparent immediately after I'd switched over from my reference Quad ESL-63/Gradient SW-63 system. The Type B's kickdrum rendition was clear and strong, with much more "weight" and acoustic size than I'd noticed before. I had no difficulty following the bass line on "Behind the Veil," but it didn't seem as distinct as I'd heard with the Quad/Gradient's free-standing woofers. Bass notes became murky and blurred when both bass guitar and kickdrum played together. On the other hand, I knew that if I set the Quad/SW-63 crossover's bass-level control too high, the kickdrum on Richard Thompson's "I Misunderstood" could turn to mush on the Quad system. This very definitely did not happen with the Type Bs, which played this selection with more or less decent pitch definition.

During casual listening, while standing next to the Snells or near a room corner, the bass was overpowering; FM announcers' voices became overly resonant and barrel-like. José Carreras's wonderfully light, lyrical tenor developed a slight nasality at the beginning of the "Kyrie" on Ariel Ramirez's Misa Criolla (Philips 420 955-2). Some tweaking was definitely in order. I set about to optimize the Type Bs' room positions, my own listening position, amplifier selection, treble level control, and speaker cable wiring.

I used the kickdrum selections to "voice" the Type Bs. First, I found that amplifier selection played a critical role. The Mark Levinson No.27, which proved to be a magical combination with the ESL-63s, did not provide the optimal control of the Type B's bass response. This was not because of a high output impedance, a problem that Kevin Voecks had raised about RH's VTL tube amplifiers. The No.27's output impedance registers only 0.08 ohms at 20Hz. Its inability to "wake up" the Type Bs in my room probably had more to do with the task of driving a complex, 6-driver, 4-way system with a 2.7 ohm impedance minima into a huge acoustical space.

Power to the rescue
The first change was to use a more powerful amplifier. Better stability and control, as well as a superior overall tonal balance, was found using the much more powerful Krell KSA-250 (its output impedance is no slouch either, being 0.13 ohms at 20Hz). Connected to this powerhouse, the Type Bs were smoother, less hard, more open, and totally effortless. This is no surprise—the KSA-250 can put out close to 1000Wpc into the speaker's impedance minima of 2.7 ohms (tweeter-level control set to maximum). As JA had mentioned to me, the KSA-250 imposes an "iron grip" on the Type B's drivers, making it an excellent choice for this loudspeaker in my listening barn—er, room.

Second, a careful adjustment of the tweeter-level control greatly helped me adjust the tonal balance. I found that boosting the treble slightly by turning the level control from 12 to 2 o'clock allowed the speaker to "open up" without becoming shrill. Third, I changed the speaker's position, moving them 1' farther out from the back wall. This move proved very important. Fourth, I found that the Type Bs produced the widest, deepest soundstage and best tonal balance when set up with bi-wired speaker cables.

Another powerhouse, the "newest" 250Wpc Bryston 4B, proved synergistic with the Type Bs. Most 4B amplifiers manufactured over the past 20 years have had a special knack for controlling woofers. For example, the 4B is the amplifier for driving the free-standing 12" dipole woofers in the Quad/Gradient SW-63 add-ons. A bi-wired set of loudspeaker cables provides the optimal arrangement for driving the Type Bs. I disconnected the jumpers between the Type Bs' tweeter and woofer 5-way binding posts, ran Levinson HF10C to the woofer terminals, Monster Cable to the tweeter terminals, and connected the other ends of both cables to the Bryston 4B's output binding posts. By then the Type Bs had been placed farther out into the room, with the loudspeaker front panel 54" from the wall. The bass became focused, developing a mild "snap" (the sonic fingerprint of all Bryston 4Bs), but did not lose any air or space. The soundstage widened and deepened, and the speakers totally disappeared. The instruments were spread out in a pleasing, authentic manner, depicting the placement and depth of the piano and drums on Dave Grusin's rendition of "Keep Your Eye on the Sparrow" (Discovered Again, Sheffield Lab 5).

Now this did not change the Type Bs' spectral profile, for their bass prominence remained. Ron Carter's string bass and Harvey Mason's kickdrum continued to be a little too prominent behind Grusin's keyboard. But the additional spaciousness and effortlessness afforded by the bi-wired Bryston 4B made the bass less overbearing in my large room. In addition, more information came through. For the first time, I realized that some of the bass beats were foot-stomps in the opening "Kyrie" of the Misa Criolla.

Now I could more easily appreciate the Type B's strengths. The midrange and treble were exceptional, with a speed, transparency, and lack of distortion I acquaint with the Quad ESL-63. For most selections, the Type Bs disappeared acoustically; I was not aware the sound was emanating from them. There was an effortlessness, so that even the most dramatic fortissimo orchestral selections, or the loudest portions of "Behind the Veil," retained their sense of air and acoustical space. Richard Thompson's voice, clear and untarnished by the kickdrum, floated between the Type Bs, well-defined and almost palpable. I found the Type Bs' transparency, lateral imaging, and depth of soundstage to be the best I have heard from any of the Snell loudspeaker line, including the flagship Type As.

Only expensive systems reveal the Type B's weaknesses. The Quad ESL-63/Muse Model 18 combination, currently retailing for $7000, played with less kickdrum emphasis, more speed, greater transparency, and a wider soundstage. The $2500 Muse Model 18 subwoofer optimized the response below 50Hz, yielding the best overall rendition of deep bass. I focused on the deepest organ notes, which are played at the beginning of the cadenza of Saint-Säens's "Organ Symphony" (E. Power Biggs, Eugene Ormandy, Columbia MS-6469, LP). Biggs holds individual notes for about two seconds each as he plays a descending scale. The Muse made each note sound as if it were a step on a staircase, with clean pitch and putting a "lock" on the room. The Type B/Bryston 4B combination played these notes, reaching the lowest, but with less definition. Switching to the $7500 (suggested retail) Quad ESL-63/SW-63 raised the transparency factor even higher, though this combination can't play the deepest bass that the Type B can with ease. The Stokowski/CSO album played over the Quad system with an enormous, seamless soundstage reaching almost beyond the walls of the listening room. This system was totally involving, particularly for classical music, but could not play as loudly or as effortlessly as the Type B.

What about the Snell flagship system, the $5890 Type A/III Improved loudspeaker? As set up in my listening room, the A/IIIi employs an external Snell crossover (add $400), a second amplifier (add $2000 minimum), plus additional speaker cables. Its advantages in my room were three: It could be moved next to the back wall, a real plus in my listening room; its bass had better pitch definition, but did not go as low as the Type B's; and it was the only loudspeaker system to show a dropping-off-a-cliff-like transient response, playing the beginning of Dorsey's "Ascent" (Time Warp, Erich Kunzel, Cincinnati Pops, Telarc CD-80106). I was startled by the explosive opening synthesizer chord. The Type B blurred the chord, while the Quads played it softly; no heart attacks with either of these speakers! Overall, the Type A/IIIi's shared the Type Bs' ability to play loud and their wall-to-wall soundstage, but were not quite as transparent as the Type Bs. In addition, the Type As did not develop the image depth heard with the Type Bs.

Conclusions
Is the Type B a large-room loudspeaker? What can the reader derive from this lengthy tale? Is the Snell Type B a great loudspeaker—dynamic, open, transparent, Class A sound at a reasonable $4200 price? Or is it flawed, beset with an overbearing bass, a 40Hz peak that interferes with the music?

I can't fully agree with either point of view. The evidence suggests that the current version of the Type B is sensitive to room size and placement. Midrange heaviness and overbearing bass were heard in two of the four listening rooms mentioned above. The 40Hz room-speaker interaction I heard (mostly eliminated in my large room) is not just a simple interaction involving a wide-range loudspeaker exciting room nodes not heard before. The Muse Model 18 subwoofer, a real foundation-cracker if there ever was one, has a well-defined deep-bass response praised by three reviewers in this magazine (RH, CG, and myself)—no disagreement on that product! No dynamic speaker-room interaction peak stood out (by ear) when I swept the Model 18 down to 40Hz and below with the sinewave generator, even standing in its nearfield. Ironically, the Type B's innovative new bass-driver system may produce too much lower bass, particularly in small or moderate-sized rooms.

On the other hand, I didn't find that the Type B's bass is a "fatal flaw." It had the best treble and midrange response of any loudspeaker in the Snell product line, and, I might add, of any dynamic loudspeaker system I've auditioned in my listening room. I had to use a hybrid reference system, the Quad ESL-63/Gradient SW-63 combination, which costs almost twice as much, to better the Type Bs' imaging and transparency; and even then, not by much. So there's real value in the Snell Type B, particularly when the bass can be optimized.

Clearly, few products have involved our staff as have the Type Bs. Love them or hate them, many words have been written about the Type Bs in a brief period, and, I suspect, will be written in the pages of other publications in the future. This alone means that the Type B is one of the most important audio products of 1991.

What can be concluded? Like all audio components, the Type B has strengths and weaknesses. Its dynamic range, ability to play effortlessly, and midrange and treble transparency are real assets. I could easily live with these beautiful-looking loudspeakers for a long time. Unlike RH, I shall feel a keen sense of loss when this product goes back to Snell's Haverhill factory. As for the cons, RH correctly identified a troublesome frequency-response peak between 40 and 60Hz. Careful room placement and adjustment of the treble control can minimize (but not eliminate) this emphasis, but it still is a bit too easy for the Type Bs to overload that bass region in small rooms. Prospective purchasers should listen carefully, take along a good pop record with plenty of kickdrum, and, if possible, audition the Type Bs at home.

I believe the Type Bs will do their best in a large listening room. Like the Type A loudspeaker, now in its 19th year and fifth version, the Type B probably will continue to sell. High on my wish list for the Type B/II, should Kevin Voecks call it that, will be a diminished bass peak in the kickdrum region and a transient speed the equal of that of the Type As. At that point, I believe that the Type B may realize its full potential as one of the finest dynamic loudspeaker designs.—Larry Greenhill