Sumiko S.9 Subwoofer Reviewed

Published On: July 27, 2015
Last Updated on: October 31, 2020
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Sumiko S.9 Subwoofer Reviewed

Brent Butterworth reviews Sumiko's new $999 S.9 subwoofer, which features a 10-inch driver, a 10-inch passive radiator, a 350-watt RMS Class AB amp, and connection options that the audiophile will appreciate.

Sumiko S.9 Subwoofer Reviewed

By Author: Brent Butterworth

Brent has been a professional audio journalist since 1989, and has reviewed thousands of audio products over the years. He has served as editor-in-chief of Home Theater and Home Entertainment magazines, contributing technical editor for Sound & Vision magazine, senior editor of Video magazine, and reviews editor of Windows Sources magazine, and he also worked as marketing director for Dolby Laboratories. He's now on staff at Wirecutter.

Sumiko-S9-thumb.jpgMost subwoofers are pretty similar, but not the Sumiko S.9. Well, it's like a few other subwoofers, but substantially different from most. For audiophiles, this is a good thing.

Sumiko's new subwoofer line is marketed as "by Sonus Faber," referring to the famed Italian high-end speaker maker, but I can't see any particular commonalities between the Sumiko products and Sonus Faber's speakers. The S.9 reviewed here packs a 10-inch, down-firing driver, a 10-inch front-firing passive radiator, and a 350-watt RMS Class AB amp. That's something of a rarity in an era when most subwoofers use Class D (digital) amps. At 15.9 inches high, it's not particularly large; and, at $999, it's not super-expensive--although it is pricier than roughly comparable factory-direct models from Hsu Research, SVS, and others.

There are also two smaller, sealed-box models: the $499 S.0, with a 6.5-inch driver and a 120-watt amp, and the $699 S.5, with an eight-inch driver and a 150-watt amp.

Anyone who knows subwoofers and/or high-end audio well can tell at a glance that the basic design of the Sumiko subwoofers was heavily influenced by REL subwoofers, one of the few subwoofer brands that diehard two-channel traditionalists endorse. Like REL subs, Sumiko subs are designed not so much to handle all the bass, as most subwoofers are, but to augment the bass response of existing speakers. The advantage is that this can make it easier to get a seamless blend between the subwoofer and the main speakers...and, as a result, a more music-friendly sound.

The most visible way in which these subs distinguish themselves is through their Neutrik speakON speaker-level input. Sumiko supplies a 10-meter-long cable with a speakON on one end and three bare wires on the other. You connect this cable to your amplifier's outputs, in parallel with your speaker cables. Thus, the subwoofer takes its signal straight from the amplifier. You set the subwoofer's crossover knob to the lowest frequency that your speakers are rated to handle (for example, maybe 40 or 50 Hz for a pair of small tower speakers).

The advantage of this setup is that the signal going to the speakers is unaffected. The input impedance of the subwoofer isn't specified, but it's likely to be at least 1,000 times greater than the input impedance of the speakers, so the amp and speaker won't "see" the subwoofer. The main speakers' signal doesn't pass through a subwoofer crossover or a digital signal processor. The speaker runs exactly as it would otherwise, and the sub just fills in with extra bottom end.

The disadvantage of this setup is that the main speakers get a full-range signal. With the crossovers built into AV surround processors and a few stereo preamps, deep bass is typically filtered out of the main speakers; this generally reduces bass distortion and lets the speakers play louder. It's rarely an issue with large tower speakers, but bookshelf speakers and smaller towers are likely to distort more if you run them full-range. Also, you or your dealer/installer will have to adjust the crossover by ear, through trial-and-error; with the subwoofer crossovers built into surround processors, little or no adjustment is usually required.

By the way, you might be wondering what the difference is between this setup and a subwoofer with a speaker-level input using standard speaker-cable binding posts. The only real difference is that the Sumiko subs (and the RELs, too) have an LFE input with a separate level knob. Thus, you can set up the subs as "bass augmenters" for stereo, then route all of the low-frequency-effects signal from Blu-ray discs and other 5.1-channel (or greater) sources to the sub only, so the really high-powered deep-bass stuff doesn't overdrive your main speakers. The LFE input is unaffected by the low-pass filter (crossover) setting on the subwoofer. It might be possible to do this with a conventional sub whose speaker-level and LFE inputs are active at the same time; you could set the LFE level using the surround processor's subwoofer-output level adjustment, provided it offers adequate adjustment range.

The Hookup
I started by plopping the S.9 into my listening room's "subwoofer sweet spot," which I've found is where most subs sound smoothest in my listening room. It's against the wall under my projection screen, between my center and front right speakers.

I used two different speaker systems with the S.9: my Revel Performa3 F206 tower speakers and some big Klipsch RP-280F towers (review to come). The electronics I used included a Classé Audio CA-2300 amp and CP-800 preamp/DAC, using a Toshiba laptop as a digital music file source. I also used my Music Hall Ikura turntable as a source, feeding an NAD PP-3 phono preamp. For surround, I used a Denon AVR-2809Ci receiver connected to an AudioControl Savoy multichannel amp.

For comparisons with other subwoofers, I used my Audio by Van Alstine AVA ABX switchbox, which permits precise level-matching and quick switching. When I set up the S.9 for some long-term listening, I used the AVA ABX as a simple remote-controlled on/off switch for the sub when it was wired to the amp. This let me easily and immediately gauge the quality of the sound with the S.9 in and out of the system.

I listened to the S.9 mostly using its intended setup, with the sub wired straight to the amp through the speakON connector, but I also tried using the LFE and line inputs.

Considering that using the speaker-level connection demands some tweaking of the crossover frequency and sub levels, and that you might want to change the level to suit different kinds of music, this thing could REALLY use a remote control. Just sayin'.

I'm going to start with a quick anecdote that illustrates what's different about this subwoofer. About the same time the Sumiko S.9 arrived, I also received a Klipsch R-115SW 15-inch subwoofer for review. Considering the R-115SW's size and its overbuilt 15-inch driver, I was eager to hear it. So I hooked up the Denon receiver and the Revel F206s, and I set the Denon's subwoofer crossover to the industry-standard 80 Hz. The R-115W delivered powerful, clean bottom end, but it wasn't blending perfectly with the Revels; the mid and upper bass lacked punch and definition. I swapped in my big Hsu Research VTF-15H; and, while the VTF-15H's extensive tuning capabilities let me get a better blend with the Revels, I wasn't quite satisfied. Then I tried substituting the S.9, and everything fell into place. The S.9 picked up right where the main speakers left off and sounded more like part of the system than like a separate subwoofer.

Sure, with more experimentation and fussing, I could have probably gotten a good blend from the R-115SW and a great blend from the VTF-15H, but the S.9 just dropped right into my system and sounded perfect with just a couple of twists of its controls. That's good because most people, and even some enthusiasts, wouldn't have the knowledge or patience to spend an hour or two fine-tuning their subwoofer.

The live version of Rush's "Anthem" from the recently released 200-gram pressing of All the World's a Stage illustrates the big plus for audiophiles: With minimal tweaking on my part, the S.9 blended beautifully with the F206s. Even though the S.9 was mostly filling in below 45 Hz, the improvement it made in the system's sound was obvious. "Anthem" starts with a guitar/bass unison run in 7/4 time played at an ultra-fast, Charlie Parker-type tempo. Without the S.9, the bass part nearly disappeared, and the guitar dominated. With the S.9, not only was the bass's contribution easy to hear, I gained new appreciation for the ultra-precise picking of the then-22-year-old bassist Geddy Lee.

"If you like bass players--as opposed to just bass--this might be the best $1,000 you could spend on a two-channel system," I wrote.

That thought was confirmed as I moved on to jazz bassist Sam Jones's album Something in Common. The opening tune, "Seven Minds," leads off with a dark, contemplative upright bass solo. Without the S.9, I could still hear all the definition and pluck in Jones's notes, but I got little sense of the body of the bass. With the S.9, I got all the body the bass should have--and a better sense of groove when the full band kicked in. Not one bit of the subtlety of Jones's playing was obscured; it just sounded appropriately full...and a LOT more satisfying, especially in the hard-grooving, extended bass solo toward the end of the tune. (Why Jones doesn't rank among the legendary jazz bassists is baffling to me.)

Basically, the S.9 made the F206s sound like the larger Revel F208s, although with smoother bass response because I was free to position the sub in the spot where it works best with my room acoustics. I found that, with music, the S.9 had enough muscle to do what I wanted it to do. Now, I didn't put on the latest Kanye West album and crank the system to the max, but I did put on the recording of the Saint-Saëns "Organ Symphony" from the Boston Audio Society Test CD 1, which has deep pipe-organ tones reaching down to 16 Hz. Not surprisingly, the 10-inch S.9 couldn't handle the deepest tones the way a good 15-inch sub can, but it did reproduce them at a modest level without apparent distortion. When I clicked the AVA ABX box's remote to go back to the F206s on their own, the tones disappeared entirely.

Click over to Page Two for Measurements, The Downside, Comparison & Competition, and Conclusion...

Here are the measurements for the Sumiko S.9 subwoofer. (Click on the chart to view it in a larger window.)


Frequency response
±3.0 dB from 29 to 110 Hz

Crossover low-pass roll-off
-24 dB/octave

The chart here shows the frequency response of the S.9 with the crossover set to the maximum frequency (blue trace) and to the 12:00 position, roughly 80 Hz (green trace). There's nothing particularly unusual about the S.9's frequency response. The response is admirably flat through the sub's useful range. For a sub that's intended to augment tower speakers, though, it doesn't go real deep; the response is way down at 20 Hz. However, for a sub of this size that uses a conventional driver and a Class AB amp, that's to be expected. Any sub of this size that delivers significant output at 20 Hz would probably have to use a very high-excursion driver and a Class D amp rated at 1,000 watts or so.

The CEA-2010A results for the S.9 are about what I expected for an audiophile-oriented subwoofer. For comparison, while I haven't measured the REL T-9, I have measured the T-7, which is a similar design with an eight-inch driver, 10-inch passive radiator and 200-watt amp. The T-7 delivers an average of 112.3 dB in the low bass (40-63 Hz) region and 97.7 dB in the ultra-low bass (20-31.5 Hz) range, so it's reasonable to assume the T-9's 10-inch driver and 300-watt amp could get it in the ballpark with the S.9's output. Larger home-theater-oriented subs, even much less-expensive models, can crush these when it comes to output; the SVS PB-1000's averages are 121.6 and 113.0 dB, respectively.

Here's how I did the measurements. I measured frequency response using an Audiomatica Clio FW 10 audio analyzer with the MIC-01 measurement microphone. I close-miked the woofer and ports; summed and scaled the port responses; then summed the combined port responses with the woofer response. I also did a ground-plane measurement (not shown) as a backup. Results were smoothed to 1/12th octave.

I did CEA-2010A measurements using an Earthworks M30 measurement microphone, an M-Audio Mobile Pre USB interface and the CEA-2010 measurement software running on the Wavemetric Igor Pro scientific software package. I took these measurements at two meters peak output, then scaled them up to one-meter equivalent per CEA-2010A reporting requirements. The two sets of measurements I have presented here (CEA-2010A and traditional method) are functionally identical, but the traditional measurement employed by most audio websites and many manufacturers reports results at two-meter RMS equivalent, which is -9 dB lower than CEA-2010A. An L next to the result indicates that the output was dictated by the subwoofer's internal circuitry (i.e., limiter) and not by exceeding the CEA-2010A distortion thresholds. Averages are calculated in pascals.

The Downside
Despite the dedicated LFE input and level knob, the S.9 doesn't, in my opinion, have sufficient deep bass extension to be the ultimate home theater subwoofer. It's good for light-duty movie viewing, but blockbuster action movies can overwhelm it.

For example, in one of my favorite deep bass test scenes, the part from U-571 in which the titular submarine passes under a German destroyer and suffers a depth-charge attack, the S.9 did a fine job of delivering the impact of cannon fire. No matter how I connected it to my system, though, it didn't reproduce very much of the deep bass rumble of the submarine and destroyer engines, or the more powerful impact of the depth charges going off.

In the scene from Interstellar where the spaceship travels through the wormhole orbiting Saturn, the S.9 distorted a lot when I pushed it to what I consider a satisfying level.

Interstellar Wormhole Scene - Near HD Quality

I'd say the S.9 is fine for audiophiles who want to watch an occasional movie through their systems or people who rarely watch action movies. Serious home theater aficionados need a more muscular sub.

Comparison and Competition
The main thing I wondered as I was listening to the S.9 was, how would it compare to an ordinary, well-engineered 10-inch sub not specifically intended for an audiophile two-channel setup? To find out, I set it up next to the $499 SVS PB-1000, a larger but less expensive 10-inch ported sub with a 300-watt amp. I connected both using only the speaker-level inputs and set their crossovers to 50 Hz (which is as low as the PB-1000 can be set) and matched their levels with an SPL meter.

The difference between the two was negligible on the Sam Jones album, so I put on "Dumb Disco Ideas" by electronic music duo Holy Ghost! The tune's deep, danceable bottom end made it obvious that the PB-1000 has more low-end presence than the S.9. However, the S.9's midbass did sound very subtly more defined, and it seemed a better match for the F206s. I have to wonder how the sealed-box SB-1000 from SVS, which has a punchier, more defined sound than the PB-1000, would compare.

Holy Ghost! - Dumb Disco Ideas

The S.9's most obvious competitor is the extremely similar REL T-9, which was recently reduced to $999 and has an amp rated at 300 watts. (By the way, all other things being equal, the S.9's extra 50 watts would net you an extra 0.67 dB of output.) I haven't heard the T-9, but I have reviewed innumerable REL subs over the past two decades, and my experience leads me to suspect that few, if any, unbiased listeners would express a clear preference for one of these subs over the other.

Of course, for about the same money, you can get a monstrous sub like the 15-inch Hsu Research VTF-15H Mk2, and you can get some awesome 12-inch home theater subs for about $700. However, I think it unlikely that the person who's seriously considering buying the S.9 is also considering those subs, or that they'd find those subs as easy to incorporate into their system as the S.9.

It's also worth noting that the S.9 looks great in its gloss black or gloss white finish, and it's compact enough that it doesn't call attention to itself.

I almost cringe thinking about some of the reviews that this sub is going to get--you know, some guy sitting around in his underwear listening to his Steely Dan hi-res files through some exotic amp nobody has ever heard of, blabbering on and on about how musical the S.9 is and what a worthy competitor it is to REL and how much better it is than those home-theater-oriented subs.

The truth is more complicated. If you look at the S.9 in terms of bang for the buck, or for deep-bass output on movie soundtracks, there are plenty of subs that can beat it. However, those subs aren't really designed to do what the S.9 does. Some of them can be made to play in a similar fashion, but you may have to work harder to get them to sound just right in your system, and subs that are built with deep-bass output as the number-one priority might never blend smoothly enough with a two-channel system to satisfy a demanding audiophile.

I think it's more appropriate to look at the S.9 in a different way. When you consider the actual improvement it can deliver to an audiophile two-channel system (especially one employing small to mid-sized tower speakers or large bookshelf speakers), how little effort it will take on the listener's part to gain that improvement, and that it won't detract from the sound quality of the main system, it's probably one of the best buys a subwoofer-less audiophile could make...because no amp, no preamp, no DAC, and no cable can make as big and welcome of an improvement as adding deeper bass to a speaker that doesn't have enough.

Additional Resources
• Visit our Subwoofer category page to read similar reviews.
Sonus faber Announces the Venere S Loudspeaker at
• Ceck out the Sumiko website for more product information.

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