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Syzygy Acoustics SLF870 Subwoofer

Syzygy Acoustics SLF870 Subwoofer

All Syzygy Acoustics’ subwoofers make subwoofing easier by addressing two major problems. First, they eliminate the need for unsightly and expensive interconnect cables, and second, they automatically equalize their output to your room. Syzygy also includes a neat app for your smartphone that serves as a comprehensive remote control.

Syzygy solves the connection problem by using a proprietary wireless link. You no longer have to run an interconnect cable to wherever you decide to place your sub; you can put it anywhere without tripping over wires. (Make that almost anywhere. You can’t place it behind furniture; apparently, that blocks the wireless signal.) A power cable is still required.

Room equalization is a harder nut to crack, but Syzygy solves that even more brilliantly by providing an iPhone/iPad app that purportedly EQs the sub for your room with the push of a button. How does the Syzygy app accomplish this noteworthy feat? The company’s website says that “using unique SoundSculpt Technology, each Syzygy subwoofer essentially makes a 3-D sonic map of its space, and then adjusts its output to smooth out the aural peaks and valleys. It sends out a series of tones that measure the shape and size of your room, the position of the furniture, and how your decor absorbs and reflects sound. This rich acoustical data is captured by your smartphone and sent back to the subwoofer where it is corrected then perfected, ensuring that the sub-bass from the Syzygy subwoofer integrates seamlessly with your speakers and the low-frequency sound arrives at your ears at the correct time. All with a tap of an app.” That reminds me of another quote, from author Arthur C. Clarke: “Any sufficiently advanced technology is indistinguishable from magic.” Whether it’s magic or technology, if it works, I like it. Maybe now they’ll figure out a way to automate setting up a tonearm. Why is that so hard? Or a wireless power connection for something more demanding than a smart watch—that should make someone rich.

The $999 SLF870 subwoofer tops Syzygy’s line of four subs. Housed in a 15″ cube, the driver uses a 12″ proprietary woven-cellulose-fiber diaphragm (pretty fancy for a subwoofer at this price point) driven by a 1200-watt BASH amplifier. The sealed enclosures are acoustic-suspension designs, which use the air trapped inside them as the spring to restore the cones to their equilibrium position. Compared to a ported enclosure, a sealed system is more linear and has better transient response, but is less sensitive, since it doesn’t use the output from the back of the cone. But with 1200 watts of amplifier power, sensitivity is not a problem. Depending on where you screw on the feet, you can aim the driver forward or downward.


Syzygy Acoustics SLF870 Subwoofer

The SLF870 is rather plain to look at, but since you probably won’t want to look at it, that shouldn’t matter. Its rubber feet are less fancy than the metal spikes found on most expensive subwoofers, but I appreciated the protection they afforded my hardwood floors. (They also provide proper spacing from the floor if you orient the drivers facing down.) You can swap the rubber feet out for spikes as a later upgrade.

To connect the SLF870 to your system, you couple a wireless transmitter to your preamp or integrated via RCA unbalanced cables. The transmitter is a 3½” x 3½” x 1¼” black fuzzy box, with two RCA input jacks and a jack for a wall-wart power supply. One transmitter can communicate with and control up to eight subwoofers wirelessly via the subs’ built-in receivers. If for some reason you actually like interconnect cables, you can use them instead of the wireless connection, though that seems like buying a Ferrari and signaling for turns by using hand gestures—a simile that’s probably wasted on younger readers.

Compared to most subwoofers, the back panel of the SLF870 is very spare, comprising an RCA jack and some status lights. That’s because all its controls are on the smartphone app. Weighing just less than 40 pounds, the SLF870 should be easy to place in your room. You can try it in different locations for maximum output, minimum intrusiveness, or best integration with your main speakers.

The SLF870 uses a fixed 24dB/octave crossover. In my experience, a sharp crossover slope like that makes it easier to match the output of a subwoofer with a main speaker, keeping midrange frequencies out of the sub and the bass out of the speaker’s midrange driver. The crossover frequency is adjustable via the smartphone app. It’s very handy to be able to sit at your normal listening position and fine-tune how the SLF870 sounds.

 

Setting Up and Using the SLF870
Like a tonearm, much of the success of a subwoofer depends on how you set it up. Since the SLF870’s technology is new and unfamiliar, I started by reading the well-written and well-illustrated 11-page manual. Most subwoofer set-up suggestions are based on home-theater applications, where the goal is to flex the walls and dump as much bass energy as possible into the room. For an audio system, what’s important is seamlessly merging the output of the subwoofer with the output of the main speaker. You shouldn’t be able to tell there’s a subwoofer in the system; instead, it should sound like the main speaker has just added an extra octave or two of bass. If the subwoofer’s response isn’t relatively flat, the challenge of matching its output to that of the main speakers is a lot harder. Then there’s the matter of speed. I tried for years to find a subwoofer that would integrate with my Affirm Audio Lumination horn-loaded main speakers, which start to roll off below 50Hz. It wasn’t until I tried the original JL Audio Fathom f110 subwoofer that I found an adequate match for my Luminations. In choosing it, I went for speed and integration rather than bass quantity. I initially used two f110s, but found I could get a better integration with a single subwoofer.

The SLF870’s truncated rubber cone feet came screwed to the bottom panel, so that the drivers faced forward, which is how I wanted them. I placed the two subwoofers just inside my main speakers, a position dictated by available space more than anything else. My JL Audio subwoofers have a continuously adjustable phase control, which I can use to compensate for different positioning, and I was pleased to find that the SLF870 also have adjustable phase, built into the app. The relative lightness of the SLF870s made the cabinets easy to manhandle into the desired positions. The transmitter offers a choice of either right and left channel inputs on RCA jacks, or a single combined low-frequency effects (LFE) input for amps or receivers designed for 2.1-type speaker systems (two main speakers and one subwoofer). Syzygy thoughtfully provides a set of RCA interconnects, though I suppose an audiophile will toss those and the flimsy power cord in the drawer and use audiophile-approved cables/cords. I did. My linestage provides right and left channel outputs, so that’s how I connected it to the transmitter. I checked to be sure my preamp’s output impedance could drive the transmitter’s 20k-ohm input impedance. It could, just barely. (How hard would it be to design, say, a transmitter with a 50k-ohm input impedance that would be compatible with a wider range of equipment? Just asking.)

Now came the opportunity to try the Syzygy set-up technology. I downloaded the Syzygy sub app from Apple’s App Store onto my iPhone 6. (An Android version of the app is available from Google Play.) I made sure the transmitter was plugged in but not connected to the output of the linestage—that would come later. I ran into several problems setting up the stereo pair of SLF870s, and finally had to call Paul Egan, President of Syzygy Acoustics, for help. It seemed that the manual’s instructions were probably OK for a single SLF870, but connecting to a pair of them was more involved. The secret proved to be setting them up one at a time. Plug one SLF870 in and set it up; then unplug it and go through the same set-up routine for the other. The subwoofer you unplug will retain the set-up information. Next, pair the transmitter with the subwoofers, which involves pushing buttons on the subwoofer and the transmitter. If that sounds easy, it is, but it could be even easier if the amplifier controls and connection weren’t underneath the subwoofer when the driver is pointing forward. Finally, use the app to mute the subwoofers and plug the RCA interconnects from your linestage, preamp, or integrated amp into the transmitter. I’d strongly suggest buying SLF870s from a dealer who can help install them. Once installed, all you have to do is play music, not fiddle with the subs. They can be set to turn on when a signal is received, or can be left on at all times—they only consume 1/3 watt when quiescent. If you set them to turn on when a signal is received, the SLF870s will emit a very low frequency whomp when they activate. It’s not loud, but it gets your attention. I rather liked the reminder that the SLF870s were operating.

After the SLF870s are set up to work in your room and are connected to your main system, you still have to match their output level with the output of the main speakers. Although Syzygy doesn’t provide a tool to help with that task, I again turned to my iPhone, using an app called OctaveRTA. This is a spectrum analyzer which uses the iPhone microphone to pick up the sound from your room. I played a recording of pink noise from audiocheck.net, and also a low-frequency sweep, which covers the range from 10Hz to 200Hz. Final tweaking of the adjustments was done by ear. The Syzygy Sub app serves as a really flexible remote control, allowing you to adjust levels, crossover frequency, phase, and several other parameters. It also lets you apply a DSP adjustment, so even after the app has equalized the response for your room, you can still adjust it if you want a different bass response. Think of the DSP adjustment as a super tone control.

Syzygy recommends 25 hours of break-in, but that’s 25 hours playing bass notes—not just turned on. That’s one break-in process I don’t want running 24/7! The subs do loosen up after breaking in.

I found the subwoofers matched my main speakers when set for a level of around 50 on the app. Other speakers and rooms will require different settings. Adjusting the level with the app was easy—just move a slider. When I adjusted the level for one subwoofer, the other one was also adjusted to the same level. Of course, my initial setting was too high, but I confess I listened to several albums that way, just enjoying the bass energy washing over me. (Does that mean I’m a closet bass-head?) Anyhow, after enjoying the surfeit of bass for a while, I forced myself to act like a responsible reviewer and dialed the sub-level back to match the output of the main speakers. You should be aware that the SLF870’s internal crossover is just a low-pass crossover, which keeps the higher frequencies out of the sub. It has no effect on the main speaker, which continues to run full-range. It would be interesting to use an external crossover like the JL Audio CR-1 reviewed by Jonathan Valin in Issue 254. A fully active crossover like that will also filter low frequencies from the signal driving the main speakers, relieving the speakers of reproducing bass and thus increasing the speaker’s dynamic range.

Sound
If you had just installed new subwoofers in your system, what would you play first to show it off? Being a classical music geek, I thought of organ music, specifically Saint-Saëns’ Third Symphony (Organ Symphony). Although my local symphony orchestra doesn’t enjoy a concert hall that sports a pipe organ, a few years ago they managed to stuff the orchestra pit with an electric organ on steroids, which could and sometimes did generate a 32Hz note that shook the concert hall and occasionally overwhelmed the entire orchestra—a memorable experience. Anyhow, I selected an album that contained the Organ Symphony and Poulenc’s Organ Concerto, as well as Barber’s Toccata Festiva, with Christoph Eschenbach leading the Philadelphia Orchestra, ripped to AIFF format from the CD layer of Ondine ODE 1094-5. Although it’s probably not my favorite recording of the Organ Symphony (I still prefer the one by Charles Munch and the Boston Symphony on Living Stereo), it’s the best-sounding recording of the symphony I have. I played the last movement, the Maestoso-Allegro, which has lots of spectacular organ fireworks. The SLF870s didn’t quite flex the walls of my room, but they still shook me. There’s a passage about 5:15 into the movement where the orchestra, which has been pretty rowdy, drops off into silence leaving the organ playing a very low sustained note. The SLF870s did full justice to that note, reproducing it with excellent pitch and lots of power. Yet the SLF870s validated the success of my efforts to integrate them seamlessly with the main speakers—I never heard them sounding like separate speakers.

Since it has bass extending to the mid-20Hz range, of course I had to try “Folia: Rodrigo Martínez” from La Folia 1490-1701, played by Jordi Savall and his band of Renaissance music specialists and ripped to AIFF from Alia Vox AFA 9805. The SLF870s projected substantial impact and power, yet integrated with the main speakers to project an impression of a realistic drum. Since the main speakers were still being powered by the normal amplifier, from the midbass upwards the system still sounded the same.

Another fave is Shelby Lynne’s album of Dusty Springfield covers Just a Little Lovin.’ On the Acoustic Sounds DSD64/DSF download, there’s a strong bass underpinning throughout. The title track opens with the bass guitar growling menacingly. The SLF870s played those lower-octave notes with excellent pitch, and although I suspect the bass on the downloaded track is overdone (the LP sounds more realistic), it was a kick to listen to it via the SLF870s—further substantiation that I really am a bass-head. Who knew?

 

Comparison
I’m not sure how useful it is to compare two 12″ subwoofers to a single 10″ model, but the latter is what I’ve been living with for the past several years, so here goes. I was most interested in seeing how the different subwoofers integrated with the main speakers—that’s what makes or breaks a subwoofer in a hi-fi system. The JL Audio Fathom f110 subwoofers sold for $2200 when last produced. They’re finished in beautiful piano gloss black lacquer and rest on three very shallow conical rubber feet. Like the SLF870s, the f110 is an acoustic-suspension design. Since it has a 10k-ohm input impedance, less than the minimum recommended by my linestage manufacturer, I use a Benchmark DAC with an analog input as an impedance buffer. The Benchmark has a sufficiently high input impedance to satisfy the linestage, along with a very low output impedance that has no trouble driving the JL Audio. The f110 has a very flexible assortment of controls, although you must pry your butt off the couch to manually adjust them. After lots of experimentation, it was obvious that the steepest available crossover slope, 24dB/octave, was optimum in matching the subwoofer output to the main speaker. In the SLF870, that decision was made for me—one less thing to obsess over.

Through the fast JL Audio subwoofer, the bass on “Folia: Rodrigo Martínez” integrated well with the extremely fast main speakers and projected deep bass with speed and detail, but the SLF870s went noticeably deeper and gave up little, if anything, in matching the main speakers. The Saint-Saëns’ Organ Symphony recording isn’t particularly detailed, so the extra energy the SLF870s projected made their portrayal of this piece much more enjoyable. When I played music with no deep bass, the SLF870s didn’t intrude: There was no audible contribution at all—which is as it should be. In other words, there was no artificial boost to the bass frequencies.

It should come as no surprise that the 12″ drivers in the SLF870s could project substantially more power at lower frequencies than the single JL Audio 10″. What surprised me is that I was able to achieve equally good integration with the SLF870s. There was no murky, lumpy bass, just powerful, punchy, detailed bottom octaves that altered (in a good way) my impression of what certain recordings sounded like. Case in point: Bass on Just a Little Lovin’ was deeper and punchier, as the Syzygy reproduced bass guitar and kick-drums more powerfully.

Bottom Line
The Syzygy SLF870 wireless subwoofers aren’t the only wireless subs available today; they are quite popular in home-theater systems, especially those using soundbars instead of discrete channel speakers. REL offers a wireless connection in its very high-end subwoofers, although at a considerably loftier price. Several other subs offer computer-assisted setup. And in setting up the woofers, I found the technology wasn’t effortless, so I had to call for help. But once the subs were dialed in, they just worked without having to diddle with them. Even when I unplugged them to change equipment, the subs “remembered” the settings. But all those techy features are pointless if the subs don’t sound good, and fortunately, they weren’t just good—they were superb. I was able to achieve a seamless transition, so the subs sounded like a continuous extension of my main speakers. I worried that the wireless connection might cause dropouts, and while I carefully monitored the sound to detect any possible problems, I never heard a single one. That’s how technology should work. Style-wise, they may be rather plain, but who really looks at subwoofers? Very highly recommended and a great value for the price.

Specs & Pricing

Type: Wireless subwoofer
Connections supported: Line-level RCA wired connection or proprietary 2.4GHz wireless connection
Driver complement: 12″ proprietary woven-cellulose-fiber diaphragm in sealed enclosure
Integral amplifier power: 1200 watts BASH
Dimensions: 15″ x 15″ x 15″
Weight: 39.8 lbs.
Price: $999

PRINCETON TECHNOLOGIES GLOBAL, LLC
P.O. Box 3035
Princeton, NJ 08543
syzygyacoustics.com
info@syzygyacoustics.com

Associated Equipment
Speakers: Affirm Audio Lumination speakers; JL Audio Fathom f110 subwoofer
Amplifiers: Berning ZH-230 stereo amplifier
Preamplifier: Audio Research LS28 linestage
Digital Sources: Toshiba Satellite laptop computer running 64-bit Windows 10 Home Premium and JRiver Media Center Version 22 music server software; SOtM sMS-1000SQ network music player with sPS-1000 power supply; QNAP TS-251 NAS; PS Audio
DirectStream DAC with Torreys operating system; Mytek Brooklyn DAC (for review)
Interconnects: Audience Au24 e balanced, CablePro Freedom unbalanced, Crimson RM Music Link, High Fidelity Cables CT-1
Speaker cables: Crimson Cables Crimson RM Music Link loudspeaker cables
Power cords: Purist Audio Design Venustas, Blue Marble Audio Blue Lightning, Clarity Cables Vortex, Audience powerChord e, Au24 SE LP powerChord
Digital: Audience Au24 SE USB
Power conditioner and distribution: Audience aR6-T

Vade Forrester

By Vade Forrester

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