Snell B minor loudspeaker

Few merchandise elicited as a lot pleasure, disappointment, and debate among the many Stereophile employees as did the Snell Type B dynamic loudspeaker (footnote 1). Both Peter Mitchell and I praised the Type B for its low-frequency extension, easy treble, excessive energy dealing with, and wonderful dynamics. Corey Greenberg and Robert Harley faulted the speaker’s sluggish and fats bass response, which they felt precluded a suggestion in Stereophile‘s "Recommended Components." Kickdrum recordings in pop and rock excited the Type B’s bass character, a attribute which was not so noticeable if one solely listens to classical music. This bass peak was so distinguished in RH’s listening room that it coloured the remainder of the loudspeaker’s vary. As a end result, he discovered that this in any other case fantastic loudspeaker was not as clear as different high-quality dynamic programs in the identical value vary.

Help was on the best way. Within six months of RH’s evaluate, Snell Acoustics launched a smaller model, the B minor, on the 1992 Summer CES. Although this announcement was overshadowed by Snell’s Digital Signal Processing (DSP) expertise, the B minor’s bass appeared to have been harnessed, even when the listening was performed in a less-than-optimal resort room. Although the B minor sells for lower than the B ($3599/pair vs $4799), it appeals for extra causes: The B minor is bodily smaller and 42 lbs lighter than the Type B; its entrance baffle is narrower; and a brand new titanium-diaphragm tweeter is used.

Technical description
The B minor has been described by its designer Kevin Voecks as being a "3½-way speaker" using one woofer, two midranges, one tweeter, and the "half": a rear-firing tweeter that overlaps the entrance tweeter’s vary. The B minor resembles Snell’s C/IV and E/III greater than it does the B. A traditional tower, the B minor’s cupboard is barely 10" vast, in distinction to the B’s 25"-wide, five-sided enclosure. (The B’s further width comes from the 2 8" "wings" of veneered wooden that flank its 13"-wide central black grille.)

The B minor makes use of a single 12" acoustic-suspension woofer, not the 2 10" items discovered within the B. Unlike Snell’s flagship Type A/III Improved loudspeaker, the B minor’s woofer strategy doesn’t make the most of bass reinforcement from the ground, because the woofer is mounted midway up the facet baffle. The 12" long-throw woofer has a solid basket body and its double-thick magnet construction permits linear, high-excursion movement. It was designed to have superior power-handling traits.

The identical midrange/tweeter/midrange configuration is used within the B and B minor: ie, the midranges are mounted above and under the tweeter (footnote 2). Snell’s Kevin Voecks means that the B minor’s slender baffle enhances its imaging skills. Like the B, the midranges and tweeter are barely offset towards the within of the cupboard, to unfold the interactions with cupboard edges out in frequency. The felt surrounds for the drivers additionally yield a smoother off-axis response. Along with the side-mounted woofers, this asymmetry signifies that the B minors are available mirror-imaged pairs.

The B minor’s tweeter is a brand-new titanium-dome unit changing the 1" aluminum-dome Vifa tweeter discovered within the Type B. The firm’s literature means that this new tweeter has wonderful on- and off-axis frequency responses and is claimed to exhibit "true pistonic conduct" all through the audible vary. It has elevated power-handling functionality due, partly, to a conjugate impedance-compensation circuit and a steep filter community. The rear-firing, ¾" dome tweeter is equivalent to the unit used within the Types B and C/IV.

The B minor’s crossover employs high-quality, non-polarized electrolytic capacitors, Mylar capacitors, and air-core inductors. The B minor’s midrange drivers cowl the identical frequency passband, 275Hz2.7kHz, with 18dB/octave low-pass and 24dB/octave high-pass slopes. The entrance tweeter takes over at 2.7kHz. The back-mounted ¾" tweeter begins to play when musical info consists of frequencies greater than 5kHz, regularly rising in quantity utilizing a first-order slope. At these frequencies, the rear tweeter contributes to the reverberant soundfield, reinforcing the speaker’s whole radiated vitality within the highs. Like the Type B, the B minor employs Monster Cable for inner wiring.

Below the tweeter on the speaker’s again panel is a connector panel with {hardware} equivalent to the B’s. There’s a rear-tweeter on/off change, a fuse holder, and a entrance tweeter-level management with steady motion. Instructions from Kevin Voecks recommended that the tweeter-level management needs to be set round 12 o’clock for the flattest frequency response. There are two pairs of five-way binding posts for bi-wiring/bi-amping. The audio system are shipped with flat metallic jumpers configured within the form of a capital "E" to permit the proprietor to drive the speaker from a single speaker cable. The barely recessed enter terminals didn’t intervene with my speaker-cable connections, which included each Sumiko OCOS and Levinson HFC-10 varieties.

The B minor’s manufacturing course of entails tuning every driver’s frequency response, with grilles in place, to inside 0.5dB of Snell’s reference grasp commonplace. This tolerance is much better than the ±45dB quoted by the distributors supplying the drivers. Each speaker is trimmed to match every loudspeaker’s amplitude response to a reference grasp. This is finished by overwinding inductors, then pulling turns off separately; beginning with smaller capacitor values and including trimmers; and, lastly, adjusting variable resistors. The tweeter-level management can also be calibrated towards the reference grasp.

The cupboard work seems to be first-rate, with fantastic match’n’endmy evaluate samples had been completed in fastidiously matched darkish walnut veneer. Cabinet sides are constituted of ¾" high-density particleboard, whereas the entrance baffle options 1"-thick particleboard. During the evaluate interval Snell added extra inner braces to the cupboard to extend rigidity. Like the B, the B minor rests on a particleboard plate and is equipped with carpet-piercing spikes.

Speaker location & changes
Detailed directions for room setup weren’t included with the B minors despatched for evaluate. As with any set up, listening revealed the audio system’ optimum room positions and toe-ins. It appeared evident that the side-mounted woofer grilles ought to face one another throughout the middle area between the audio system. Via phone, Kevin Voecks advised me that the B minors had been designed for use out within the room, not towards the again wall. (This could be very totally different from the corporate’s Type A/III, which was designed by the late Peter Snell to hug the wall and never intrude into the room area; it trusted boundary results to assist its deep bass.)

Listening-room dimensions are important for any loudspeaker, and maybe notably so for the Type B. After RH’s important evaluate, JA puzzled if the B had been designed "by tuning its bass for maximal flat low-frequency extension beneath anechoic circumstances." Thus, it might "are inclined to sound bass-heavy in an actual moderate-sized room." The B’s highly effective bass is likely to be higher balanced in a big room. I examined the Bs in my very giant listening room (5500ft³, with an efficient room size of 52′), and reported the ends in February 1992. Readers ought to seek the advice of that article (Vol.15 No.2, p.181) for particular particulars of my room’s development, precise dimensions, contents, listening positions, rugs, home windows, bass modes, and outcomes of Snell’s room-analysis software program program (footnote 3).

I concluded that the Type B’s overgenerous bass may very well be balanced in order that it was not overpowering, however solely after cautious setup and room positioning. The audio system needed to be positioned 54" from the again wall and pushed in bi-wired mode by sure solid-state amplifiers (eg, Bryston 4B or Krell KSA-250). Though improved, the B’s bass prominence within the kickdrum area was nonetheless noticeable. Would the B minors require the identical time-consuming setup to keep away from bass issues?

I started my evaluate by putting the B minors close to the room’s slender again wall, as recommended by Snell’s room-analysis software program. The B minors had been positioned 24" between the rear of speaker enclosure and the wall, which put the loudspeakers’ entrance panels about 45" from the rear, 36" from the facet partitions, and 84" aside. The audio system had been toed-in barely. My listening place was 18′ away from a middle line between the audio system, and the seat positioned my ears about 34" off the ground (concerning the degree of the B minor’s tweeter).

I then adjusted the tweeter-level controls. As Voecks had recommended, I discovered that the 12 o’clock setting gave the most effective treble response for my style. After this, I did the "sit down, arise, stroll round" process with pink noise, and located that neither on- nor off-axis treble responses differed markedly. I later tried different positions, however this preliminary setup proved to be the most effective.

Like the Type Bs, the B minors produced the most effective tonal stability when arrange with bi-wired speaker cables. I disconnected the jumpers between the B minor’s tweeter and woofer five-way binding posts, and linked the double spade lugs on the finish of every parallel run of OCOS cable.

I swept the loudspeakers with a Heathkit sinewave generator earlier than I started listening to music. When I’d performed this with the Type B, I’d heard the bass enhance markedly as I swept the frequency down previous 42Hz, very close to the crossover level between woofer and subwoofer. When I’d moved across the room, there have been variations within the amplitude of this bass notice, suggesting that room modes had been being excited.

Not so with the B minor. No 42Hz prominence was discovered in the course of the room sweepsonly a slight enhance in output between 47 and 60Hz. Sweeping downward, I used to be capable of hear the low-frequency response clearly all the way down to 35Hz; this differed from the B, the place I’d discovered detectable output all the way down to 28Hz (footnote 4). So far, so good: The B minors had been straightforward to arrange, and had a a lot much less distinguished bass emphasis.

Listening
I’ll minimize to the short. Yes, the B minor had a light midbass peak in my listening room, but it surely was not as distinguished or overpowering as that of the Type B. The excellent news is that this extra felicitous tonal stability allowed the Snell B minor to picture properly, present better midrange and treble readability, and play with transparency.

I examined the B minor’s bass efficiency with quite a lot of musical sources: rock recordings for kickdrum bass peak; male vocals, together with FM announcers, for upper-bass extra; organ and synthesizer recordings for deep bass; and synthesizer recordings for bass transient pace.

First I replayed all of the musical picks that had provoked the Type B’s misbehavior in my listening room, and that meant rock studio recordings that includes kickdrum. The B minor did higher than the B with "Behind the Veil" from Jeff Beck’s Guitar Shop (Epic EK 44313). When bass and kickdrum performed collectively, bass notes remained extra distinct than that they had on the B. The drum package had beneficiant bass slam and snap with out being overblown. The kickdrum on Richard Thompson’s "She Misunderstood," from Rumor & Sigh (Capitol CDP 7 95713 2), confirmed respectable pitch definition, however didn’t overpower the opposite devices when performed over the B minors.

Next I checked the replica of male voice. The B minor didn’t coloration the voices of FM announcers. (The Type B had produced overly resonant and barrel-like FM voicing.) José Carreras’s splendidly mild, lyrical tenor remained pure and open with the B minor, displaying little of the nasality heard with the B at the start of the "Kyria" on Ariel Ramirez’s Misa Criolla (Philips 420 955-2). Harry Connick, Jr.’s rendition of "I Don’t Get Around Much Anymore," from the When Harry Met Sally… soundtrack (Columbia CK 45319) was clear with none of the added heat and overly resonant low frequencies heard with the B.

Footnote 1: See PWM’s CES report (Vol.14 No.9, p.51); RH’s evaluate (Vol.14 No.12, p.130); my Follow-Up (Vol.15 No.2, p.181); and "Manufacturers’ Comments" with JA’s replies (Vol.14 No.12, p.263 and Vol.15 No.6, p.291).

Footnote 2: Many name this a "D’Appolito" configuration. However, designer Joe D’Appolito’s unique idea concerned the usage of 18dB/octave acoustical crossover slopes to get the optimum evenness of vertical lobing from the array. Not all vertical MTM drive-unit arrays are D’Appolito arrays.John Atkinson

Footnote 3: Snell supplied me with a duplicate of the Room-Analysis Computer Program, CARA, and LEO. These applications analyze room-resonance mode distribution and recommend speaker/listener areas for every dimension of the listening room that minimizes bass nodes. The B minors had been positioned within the room in response to one in every of LEO’s options for a "higher" location ("greatest" couldn’t be simply estimated).

Footnote 4: These frequency-response measurements are purely qualitative and don’t characterize the loudspeaker’s true efficiency. However, they do yield a way of the room-speaker interplay, and are used to substantiate sure subjective impressions.

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November 10, 2023 at 05:13PM