Benchmark SMS1 Speaker Review

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Classic Looks, Definitely. Classic Sound?

Brent Butterworth

Benchmark's SMS1 bookshelf speaker has an unusual genesis. The company's known for high-performance digital-to-analog converters, but expanded its line. It added the AHB2, the first power amp to use THX Class AAA all-analog, high-efficiency amplification technology, and it launched its first speaker, the SMS1.

The SMS1 represents a collaboration between Benchmark and speaker designer David Macpherson, the creator of the Studio Electric line of beautifully designed, idiosyncratically retro speakers and amps. It's a two-way design that basically keeps the retro look, although it's toned down a bit compared to the Studio Electric line. Macpherson said that the speaker's similar from an engineering standpoint to his existing two-way monitor, but Benchmark's engineers helped him to refine the crossover circuit layout and acquire tighter-tolerance parts than he could source on his own.

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Benchmark SMS1: Features and Specs

Brent Butterworth

• 6.5-inch polymer cone woofer
• 1-inch fabric dome tweeter
• five-way binding posts and Neutrik SpeakON jack for speaker connection
• biamp/normal switch
• mahogany or paduk side panels available for an additional cost per pair
• 13.5 x 10.75 x 9.87 in / 345 x 270 x 145 mm (hwd) • 23 lbs / 10.4 kg each

The SMS1 is a little unusual in that it's an acoustic suspension (sealed box) design. Most speakers use ports, which generally means their bass response goes deeper but it declines at a steep -24 dB/octave below the box resonance. Acoustic suspension designs don't usually go as deep, but they roll off more gently in the bass, at 12 dB/octave. Many audiophiles feel that acoustic suspension speakers deliver better pitch definition and punch than ported speakers. In fact, I used to be a hardcore acoustic suspension guy, although I've since made my peace with ports.

Also unusual is the pro-style Neutrik SpeakON input jack, which you have to use if you want to biwire or biamp the SMS1. Don't worry, there's still a conventional set of binding posts you can use; you just can't biwire or biamp with them. A switch changes the speaker from conventional wiring to biwire/biamp mode. BTW, the biwire/biamp mode lets you make separate connections to each driver, which isn't a big deal but many audiophiles feel it can have certain advantages.

The metal mesh grilles look very cool and are much heavier than a typical fabric or perforated metal grille. You can read about the effects of this grille on the sound in the measurements section of this review.

I used the SMS1 mostly with my usual system, including a Krell S-300i integrated amp fed by a Sony PHA-2 DAC/headphone amp. Later, I used it with Krell's new Illusion preamp and Solo 375 monoblock amps. I listened with the grilles on and off; the difference was audible, but couldn't decide which I preferred; the sound was maybe a hair on the dark side with the grille, and a hair on the bright side without. So I left them on because the speakers just look so good with them.

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Benchmark SMS1: Performance

Brent Butterworth

For me, reviewing speakers is a little like online dating. Regardless of what you might learn in advance from a website, you can never really tell what you're going to get until you encounter it in person. And the first thing you notice is the obvious flaws.

After just a couple of minutes of Thrasher Dream Trio, a jazz album featuring drummer Gerry Gibbs, pianist Kenny Barron and bassist Ron Carter, I realized, "I'm really enjoying this!" I didn't hear any of the kinds of flaws that would normally distract or discourage me when first "meeting" a speaker. No obvious "cupped hands" coloration from the woofer. No boom in the bass. No major frequency response anomalies. No edge, grit, glare or grain. Just really good sound.

A lot of speakers sort of hit you over the head with imaging and soundstaging, as if to yell, "HEY! I'M IMAGINING HERE!" A lot of audiophiles like that, but as I learned from reading the work of Stereophile founder Gordon Holt, the longer you listen and the deeper you get into this hobby, the more you value accurate tonality instead of sonic spectacle. To me, the SMS1's imaging in the thrasher Dream Trio's rendition of "Tell Me a Bedtime Story" sounded just right. I could hear all the instruments precisely imaged between the two speakers, and a little to the outside of the speakers, but not in a way that called attention to itself. I got Gibbs' drum kit spread out across about a 7-foot width of my living room -- like a real drum kit -- and Barron's grand piano stretching just slightly further across. I could close my eyes and point to each drum in the kit. But I never thought "WOW!" I just enjoyed the sound, never once distracted by a flaw or even a characteristic of the speakers.

I actually did think "WOW!" when I put on Toto's "Rosanna," because so many speakers reveal their flaws instantly on this cut but the SMS1 didn't. It sounded dynamic and clear, without distortion or obvious coloration. Even the vocals in the recording, which tend to smear into one sonic blob, sounded distinct enough that I could identify the position of each vocalist in the "Not quite a year since you went away...." section. Being a 6.5-inch two-way, the SMS1 didn't have the capability to play the deepest notes from the bass guitar and kick drum with real authority, so the sound of this dense recording did seem slightly bright. But I can't think of a two-way speaker that doesn't sound a little bright on this tune. The bass does have a lot of kick, though; the woofers had no problem pounding out the kick drums and electric bass notes in Mötley Crüe's “Kickstart My Heart” at high volume.

Except perhaps on heavily produced pop recordings, the SMS1 has a slightly romantic sound that I don't want to call "dark," but more like ... chocolatey? (Yeah, I know: Julian Hirsch just turned over in his grave. Sorry.) Somehow when listening to Larry Coryell and Philip Catherine's acoustic guitar duet album Twin House, I got lots of detail but none of the edginess and brightness that so often make me have to turn the volume down when I listen to this recording.

I did notice one characteristic that I'd call a coloration: a slight wrinkle in the lower treble response that makes voices sound subtly emphasized and clearer, if also slightly less natural. I heard this on two of my favorite test tracks: Holly Cole's "Train Song" and James Taylor's live version of "Shower the People." I can't say it ever distracted me or bothered me, but it's worth noting if you're looking for more of a Sinatra-style smoothness throughout the vocal range.

Anyone who needs to be sold on why high-end audio is worth the expense would probably be persuaded if they hear saxophonist Gene Ammons' recording of "But Beautiful" ​through the SMS1. You get a gorgeous, almost glowing rendition of Ammons' big, romantic sound; portrayals of drums and piano that sound accurate and realistic without sounding over-realistic, and a natural sense of space that captivates you without trying to wow you.

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Benchmark SMS1: Measurements

Brent Butterworth

This chart shows the frequency response of the SMS1 on axis (blue trace) and the average of responses at 0°, ±10°, ±20°and ±30° horizontally (green trace). The flatter and more horizontal these lines look, the better the speaker usually is.

This isn't a real flat response, but if you look closely you can see there's some good stuff going on here. From 200 Hz to 2.2 kHz, the response is pretty close to dead flat, suggesting this speaker has a very smooth midrange -- and midrange is the most important range because that's where voices reside. That little cancellation dip at 3.4 kHz may look scary but it's unlikely to be very audible because it's narrrow. What is likely to be audible is that the tweeter response is down about -2 dB from 2.3 to 9.5 kHz. It's such a broad, mild and mostly smooth dip that it probably won't show up as an overt coloration, but it will probably give the SMS-1 a slightly mellow sound. Off-axis response is very good, with very little roll-off below 10 kHz and no significant dips showing up as you move to ±30°. The big metal grille does cause some difference in frequency response, most notably a drop in response of about -1.5 dB between 4 and 5 kHz, as well as a similarly sized dip at 10 kHz and peaks at 8 and 13 kHz.

Impedance averages 7 ohms and dips to a low of 3.0 ohms/-11° phase at 122 Hz. So the average impedance is no problem, but if you connect this speaker to a cheap little amp and you get a powerful bass or guitar note or drum hit around 120 Hz, it could cause the amp to shut itself off. But seriously -- are you really going to connect an expensive speaker to a cheap little amp? Anechoic sensitivity measures 83.4 dB at 1 watt/1 meter, so figure somewhere around 86 dB in-room. That's a little below average: You'll need 32 watts to hit 101 dB; I'd recommend at least 50 watts per channel and preferably 100.

I measured the SMS1 with my Clio 10 FW analyzer and MIC-01 microphone, at a distance of 1 meter atop a 2-meter stand with the mic on the tweeter's center axis; the measurement below 240 Hz was taken by close-miking the woofer.

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Benchmark SMS1: Final Take

Brent Butterworth

Two-way speakers are difficult to design; as I've written elsewhere, it's tough to get good bass response (which requires a large woofer) while getting a smooth blend between the tweeter and the woofer (which require a smaller woofer). But I can honestly say I enjoyed listening to the SMS1. If you're looking for a high-end bookshelf speaker -- or even just for a good speaker, period -- you should give this one a listen. I think you'll realize, as I did, that after the first couple of tunes, you're blown away not by how spectacular the sound is, but how good it is.