REL Raises The Bar

The new no.31 Reference Subwoofer is a substantial improvement.

If you aren’t paying close attention, you might easily mistake REL’s new no.31 subwoofer for one of their outgoing reference models. Upon close inspection, aside from the new super-coolio carbon fiber badge, the rear facets of the cabinet top are beveled – a further effort to refine the shape and eliminate resonance.

We often discuss break-in time in terms of days and hours, yet the difference between the no.31 and RELs past is immediate. The no.31 is faster, more nimble. If you only think of the low-frequency augmentation provided by a subwoofer as a single sonic shade, be prepared to have your paradigm reset.

Those familiar with the effect of adding one (or more) REL subwoofers to their system, will be equally impressed. John Hunter and his team have pushed the possibility of what a subwoofer can add to a high performance audio system further than ever.

$7,000 ea.

Please click here to visit the REL site, for full specifications. We’ll have a full review shortly.

REL’s new T/x subwoofers

Listening to the speed, detail, and delicacy of the bass line in Sly and The Family Stone’s “It’s a Family Affair” proved the impetus for where this review is heading.

A distinct trend in product design, both in and out of the high-end audio world, lets the junior designers cut their teeth on entry-level products in the lineup. This isn’t a terrible idea for many reasons, but the main ones are probably risk management and damage control. If the new person screws up on a small scale, all is not lost. Not to mention the new people can often pull a bit of genius maneuvering, so it can actually be a big win.

Like one of those personality assessments, there’s no real wrong answer here. However, this approach can often detract from the cohesiveness of a product lineup. A recent discussion with REL’s head designer, John Hunter, reveals that he had just as much of a hand in creating the new lineup as with the no.25 – and this is obvious the minute you fire up these new subs. REL sent us a pair of each model, and thanks to their small size, they are easy to work into any décor.

Please click here to go straight to the REL site for those wanting the exact size, weight, and electrical specifications. If you don’t have a REL dealer nearby to assist you, there is an excellent “subwoofer finder” section that will pair the right REL sub to the speakers and room that you have now.

To make a long story short, the T5/x utilizes a 125-watt Class AB amplifier connected to an 8-inch downward-firing woofer. The T/7x has an 8-inch front-firing active driver, a 10-inch, downward-firing passive radiator, and a 200-watt Class AB amplifier. The top of the range T/9x offers a 10-inch front-firing active driver and a 10-inch passive facing down, coupled to a 300 watt Class AB amplifier.

If you aren’t familiar with REL subwoofers, the original T series made its debut in 2006, replaced by the T/I series in 2015. The jump in performance from the T to T/I was dramatic, and REL’s own copy describes it best, “these were softer, slower, and not as potent in output, as their flagship designs.” The T/I series was faster, with more detail and nuance – now REL had a modest priced subwoofer that could keep up with a pair of panel speakers or a small pair of mini-monitors.

Many manufacturers prefer to connect via line-level connections, and some take it even further by having a built-in crossover that will pass sound from about 80hz or so on to your main amplifier and speakers (letting the sub do the rest, in the hope of taking some of the load off your main amplifier). REL has always chosen to use a high impedance connection at the speaker terminals. This makes for better integration between the main speakers. It also passes through the complete character of your amplification chain to the subwoofer.

Fear not, if you have to connect your REL (or pair of RELs) by line-level output, they will accommodate that, as well as connecting via a .1 LFE input. It might be confusing to some that REL does not pass upper frequencies through the REL, they just affect the point at which the sub begins to play, variable from about 30hz to 120hz. So, in essence, you are using the crossover level control to dial upper bass out of what the REL is producing. Having used RELs for over a decade in various systems, the lower you can go on your main speakers, the better integration you will have with them. That being said, I have achieved incredible results using RELs with the KEF LS50 and various iterations of the LS3/5a. But it will take more setup time. And, should cables be inconvenient, you can take advantage of RELs wireless “arrow” system to do away with the cables entirely.

REL has some excellent setup tutorials on their website and in the instructions that come with their subs, so I won’t go into great detail here. However, REL prefers you to work with the room corner if possible, and that was no problem in our setups.

Chicken or egg?

Several things affect how much sheer output a subwoofer can produce, along with the quality of the low-frequency signal produced. If you’ve ever modified anything with wheels, you know that if you add more go, you need more stop, and if you add more stop and go, chances are you need some suspension upgrades to keep that newfound performance sticking to the ground. It’s the same with subwoofers. When redesigning the /x series, a slight increase in cabinet volume led to the ability to achieve more extension, which meant the overall subwoofer could be driven harder (louder) without suspension/cone distortion. So, as a result of many changes to every aspect of these subwoofers, practically a new series is born. They outperform the units they replaced by a considerable margin. I borrowed a T/9i from a friend to get some valid side-by-side comparisons with at least one of the range.

Most listening was done in a 13 x 18-foot room (usually populated by a six-pack of REL S/510s) with Eggleston Nico Evolution speakers or the new Harbeth C7s. We feel a $5000 pair of high-quality main speakers is a logical candidate for a pair of subwoofers in this range. Not wanting to overly dwell on this, but it is important to note when comparing the quantity, quality, and overall character of the /x series to the six-pack of S/510s and even the flagship no.25s, there’s no question these products came from the same mind.

Even in their least expensive models, REL does not dilute any of their core attributes. From the quality of the connectors used to the attention to detail in final assembly, and ultimately to the quality of the finish applied, the gloss and complete lack of surface imperfections (remember, I’m a crazy car guy – I pay close attention to this stuff) is just as subtle on the $679 T/5x as it is on the $7,500 no.25. That’s devotion to excellence.

Comparison one: Visual

The first thing you might notice when comparing the new /x series to the outgoing /I series is the rounded corners of the /x, giving the new models a little bit more elegant feel – dare we say a little more room and user friendly. The /x subwoofers are available in gloss black and gloss white – of course, you’ll have a preference. Though black has always been the rage for subwoofers (especially if you have gloss black main speakers), white really disappears in the room nicely. Let’s face it, if that’s the most challenging decision you have to make today, life is indeed good.

Comparison two: sonics between old and new

As mentioned earlier, only having the T/9i for comparison, it doesn’t take more than about 30 seconds to hear improvement in every way. After dragging out the standard REL test tracks from the Sneakers soundtrack, and Jennifer Warnes’ “Ballad of the Runaway Horse” to finesse integration between speaker and sub with both woofers, it was easy to compare and contrast.

Moving on to our own LF warhorses, “Pulp Culture” from Thomas Dolby, “Bug Powder Dust” from Kruder & Dorfmeister, and Jaco Pastorius’ self-titled album, it’s easy to see that all of the marketing departments claims have been met, and exceeded. That REL is only charging $200 more for the T/9x (and incrementally less for the other models) underscores their commitment to providing an excellent product at an approachable price.

The improvement from old to new is a definite increase in speed and sheer output capability. Where the /i could be bottomed out when playing the Thomas Dolby track really loud or playing a long playlist of electronic music at a similar volume, the new /x model is cleaner, more dynamic, and does not have the woofer cone flattening out. If this makes sense, there’s more air in the bass, which increases the upper bass/midrange presence provided by the REL in the first place, an even bigger delta when switching it on and off. And this is with a single woofer. There’s a greater sense of ease with a pair.

Final comparison: between small, medium, and large

All three models share a similar overall character, but bigger main speakers and more room volume will demand a bigger woofer. In the 11 x 10 back bedroom system, with the KEF LS50s, paired with the Luxman 550 integrated that was recently reviewed, the T/5x was more than enough to achieve a perfect balance. 20 watts of high current, class A power made for an incredibly musical system.

In our 13 x 18 room, the T/7x was able to fill the room better, especially at higher levels. Depending on the system, speaker, and volume level, deciding whether the 7 or the 9 is the better model will depend on your wallet. If you have a relatively budget system, the 9s might be overkill, but the better your system and discerning your ear, stretching for the top ones is the way to roll. Especially if we are talking pairs. The T/9x turns in a very respectable performance with our Dynaudio Confidence 20 speakers mated to the Boulder 866 integrated, our new reference in that room.

What the new REL /x subwoofers bring to your system, in addition to more bass output, is a higher level of definition in the lower frequencies, as well as more presence in the entire frequency spectrum. Don’t believe me? Listen to them for an hour and have a friend shut them off while remaining at your listening position. Better yet, have your friend do it while you’re listening to music with barely any low-frequency content. It will grab you instantly. The best way to really experience what any REL subwoofer can do is to shut it off. The 30 seconds you hear your system with it disabled will convince you. That’s truly all it takes.

We are happy to award the REL/x series one of our Exceptional Value Awards for 2021. These are fantastic subwoofers. You owe it to yourself to experience them if you are in the market.

T/9x $1,449

T/7x $1,099

T/5x $679


Digital source Boulder 866 internal DAC

Cable Tellurium Q Ultra Black

Speakers EgglestonWorks Nico Evolution, Harbeth C7ES-XD, Dynaudio Confidence 20

The REL 212SE Subwoofer

Actually, two of them.

As REL’s John Hunter will tell you, you need a pair of 212SEs to disappear in your room, and that is the ultimate goal of a sub-bass system, to prove a transparent extension to your main speakers, never drawing attention to themselves. While the uninitiated might opt for small cubes that can be placed a bit more out of the way, Hunter explains it succinctly: “When you hear low-frequency information out in the real world, it doesn’t just come at you from off in the corner, it envelops you from all directions.” Thus, the height factor of the 212SE is equally important to disappear audibly.

After Hunter spends a bit of time optimizing my Focal Sopra no.3s for perfect positioning, blending the 212SEs into the rest of the system takes place quickly. When complete, the subs are impossible to localize, and in addition to the lower register improving dramatically, the entire presentation takes on greater depth, width, and height. The Sopra no.3s and the 212SEs work together as one. Perfectly.

As the music is playing, Hunter says, “Ok, now we’re listening to about $300k worth of gear, right?” Then with a quick flick of two switches and a wry smile, he turns the 212SE’s off and says, “Now we’re listening to $292,000 worth of gear.” The difference is staggering; the soundstage completely collapses. Considering the $8,000 that a pair of 212SEs will set you back, won’t even buy a power cord from some manufacturers, this is amazing. The delta achieved by including the pair of 212SEs in my reference system is more than just a 100% jump, I no longer can listen to the system without them in. Adding a pair of these subwoofers to get this improvement for less than 3% of the total system cost is unbelievable.

It’s not the bass; it’s everywhere

The level of depth that the pair of 212SEs adds to the mix is just as exciting as the low-frequency extension. The delicacy of the opening Fender Rhodes licks in the Springsteen classic “Kitty’s Back,” waft through space between my Focal Sopra no.3s so gently, it sounds better than when I’ve sat ten feet away from one in a club. This stunning realism is the key to the 212s presentation. As it says on the REL website, their goal is to restore midrange warmth and harmonic structure. This deceptively simple goal, nearly impossible to achieve, is a promise that has never been delivered in my listening room until now.

Tracking through myriad cuts deliberately lacking substantial LF content reinforces the initial experience. Whether listening to Ella Fitzgerald or Eddie Mercury, my system has more bloom, more dimensionality. The music comes alive in all dimensions more clearly, with more low-level information present at all volume levels. Enticing as giving the volume control a hearty spin is, it’s still good at low volume.

These subwoofers have been a serious threat to productivity. The experience they’ve added to my primary reference system keeps me glued to the listening chair, at times for hours, at times for the entire day. With so much more musical information available, listening becomes sheer joy again.

It’s almost better than real

Because of the power required, lower frequency extension and detail is usually the first thing to give up the ghost when pushed, followed closely by overall system imaging. Depending on your room, system, and available power, it happens gradually or in a brick wall fashion. For the first time in nearly 40 years, this didn’t happen, no matter how loud the music was. The REL 212SEs offer no trace of distortion, compression or fatigue. Even when hitting nearly 120db peaks in my 16 x 25-foot listening room.

Fun as this is, be careful should you attempt this at home, OSHA says you should not be exposed to music at this high volume level for more than about 10 minutes. Just enough to listen to Pink Floyd’s “Breathe” in a way I’ve never experienced it – not even live. Whether you jump off the cliff for a pair of 212SEs or even one of REL’s smallest offerings, the musical force that comes with having a great sub-bass system will make it tough, if not impossible to go back. You can’t unhear it.

Inside the black box

We can go on and on about the tech inside the 212SE, but from the listening chair, it’s all about execution and level to detail. That’s why the 1.6-liter engine in a Kia makes 150 horsepower on a good day, and the 1.6-liter engine in a contemporary F1 car makes almost 900. Make no mistake, REL is the Ferrari F1 of low-frequency reproduction. Full specs are available on the REL site here:

The 212SE looks conventional from a distance, a big black box with woofers in the front. A closer look reveals that the two front-firing 12” continuous cast active drivers are paired to an additional 12” passive cone on both the rear and bottom. The passive cones use the same material as the active drivers, providing sonic consistency. REL claims that the two passive drivers not only add dimension to the bass produced giving the 212SE the equivalent of a pair of 17-inch drivers. Driving each of these woofer arrays is a 1,000-watt amplifier, optimized for its job.

Closer inspection reveals numerous fine details; the finish is exquisite. Not only is it the equivalent of anything I’ve seen on a six-figure pair of Wilson or Magico speakers, but it’s also the equivalent of anything I’ve seen on a Bentley. The gloss black on the review 212s is liquid in appearance, and this reflective quality helps it to physically disappear in the room. Even the complexity of the machined shape in the side handles reveals a level of attention that tells you this is indeed a special product.

For those not familiar with REL, they use a speaker level connection, requiring your main speaker’s run full range, so the signal going to the subs has the same sonic signature of what is going to the mains via your power amplifier. They can be used via line level inputs as well, but whenever I’ve tried this with a REL subwoofer, the results were never quite as good as doing it their way.

Should running a cable be inconvenient, REL subwoofers can also be connected via their Longbow wireless transceiver. The Longbow is a compression-free wireless system, utilizing the same speaker or line level outputs, transmitting wireless information effortlessly. While this option was not taken here, it has been used with other REL products with excellent result.

And the winner is

The combination of dynamics and musicality that a pair of REL 212SEs add to the mix is of such high quality, I had made up my mind after about 10 hours of listening (I was up until about 4 a.m. after Hunter left, the day he installed them) that this would be our product of the year. For my money, this could be TONE’s product of all time.

I’ve had the privilege to own and evaluate thousands of components in the last two decades. Nothing has ever come close to achieving so much at such a modest cost. $8,000 is by no means chump change, but when other companies are asking ten times this for wire, that they claim is a “component level” upgrade, I call shenanigans. If your system doesn’t go to 11 right now, a pair of these will get you there. And if it already does, hang on; you’re still in for a ride you aren’t expecting.

In the end, I’m not sure what freaks me out more, that a pair of REL 212SEs are this good, or knowing that there are two more models above the 212SE.

The REL 212SE Subwoofer

$4,000 each, two used in this review


Analog Source                        Grand Prix Audio Monaco 2.0w/triplanar arm, Lyra Etna

Digital Source                         dCS Rossini DAC and clock

Main Speakers                        Focal Sopra no.3

Preamplifier                             Pass Labs XSPre

Phono                                      Pass Labs XSPhono

Amplifiers                               Pass Labs XS 300 monos, XA200.8 monos

Cable                                       Cardas Clear, Tellurium Q Black Diamond

Racks                                      Grand Prix Audio Monaco

Choosing the Best Subwoofer for Your System

If you’re subwoofer curious, but not sure which way to turn, you’re not alone. We asked the folks at SVS to share some of their tips with us. Here’s their advice on how to choose the best sub for your HT or 2-channel system:


Bass is the sonic foundation of all movies and music, and when you want palpable, room-energizing bass, there’s no substitute for a high performance home subwoofer. The low frequency energy generated by a subwoofer can be incredibly subtle, like the pluck of a bass guitar string, or an all-out, chest-thumping assault on your senses, like an explosion filled car chase in a movie.

On their own, most loudspeakers don’t come close to generating the levels of low frequency extension and bass output as a powered subwoofer, and in many instances, subwoofers are one of the most impactful sonic upgrades you can make to a home theater or audio system.

With all the different subwoofer choices out there including ported and sealed models, different amplifier power ratings, and driver sizes that range from 8-inches up to 20-inches and beyond, it can seem daunting to find the best subwoofer for your room and listening tastes. To make it easier, we’ve listed some key variables to consider.

Décor and Room Integration

Successful integration of audio equipment with home decor is a high priority for many enthusiasts. When thinking about how a subwoofer will fit within your living room, home theater or other area, this is what you need to know:

Overall Size/Footprint: A subwoofer needs to fit into the allocated location without blocking or altering normal foot traffic patterns. For planning purposes, use the ‘real world’ footprint dimensions of the subwoofer, which includes the grille and some extra space for the power cord and signal cable. In locations where floor space is tight, consider a sealed box subwoofer, which tend to be more compact than their ported counterparts.

Finish Options: Most subwoofer manufacturers, SVS included, offer several finish options to complement your loudspeakers and other AV components. Piano gloss lends a high end feel to a home audio system and is perfect for upscale decors. Consider a more durable and scratch resistant black ash/oak or other wood grain finish for high-traffic areas with kids and pets or to match a classic wood look. In dedicated home theaters where the lights are dimmed, lower reflectivity finishes will help minimize light glare.

Room Size and Playback Level

Room size and layout has a major influence on subwoofer performance. Large rooms with open floor plans and vaulted ceilings require a more powerful subwoofer to deliver a convincing bass experience. Another option when feasible is to go with dual subwoofers since two smaller subwoofers generally offer better bass performance across the entire listening area, than a single large sub. You can read about some of the other benefits of having two or more subwoofers here: Why Go Dual.

In addition to room size, your preferred system playback level also has a significant influence. If you like to push your home audio system to loud levels (like an IMAX theater) and want to generate sound pressure levels that let you ‘feel the bass’ from action movies and music, consider a larger subwoofer with a higher amplifier rating and a bigger driver to achieve extreme performance. Conversely, if you listen at more moderate levels, a smaller and less powerful powered subwoofer can deliver a no-compromise experience that enhances all your audio content, and will also be easy to integrate in your room.


Most people don’t have unlimited funds to spend on bass, so budget is an important factor. High performance subwoofers require massive magnets and motor structures as well as powerful internal amplifiers, which makes them heavy. Cheaper lightweight subwoofers simply can generate the same amount of bass and SPLs to the limits of human hearing as larger, heavier models, which almost defeats the purpose of adding a subwoofer. You should be prepared to spend at least $500 for this level of performance in a small to medium sized room and more for larger rooms.

Common Home Audio System Applications

Below are some SVS subwoofer model recommendations for common system applications. While these recommendations are a good starting point, contact SVS for an expert consultation and comprehensive system evaluation to make sure you are choosing the best model.

PC-Based Audio System: Usually situated in an office, bedroom or den, a compact sealed sub like the SB-1000 subwoofer is a natural choice for PC-based audio systems, and it can fit almost anywhere in the room, even behind the PC monitor or under a work desk.

Secondary Home Audio System: Bedroom or Media Room: This increasingly common application typically involves a wall-mounted HDTV, some type of media streaming device, and a sound bar or small satellite speakers. Consider the SB-1000 or the slightly larger and more powerful SB-2000 subwoofer for a great combination of sound quality, performance and compact size.

Primary Media System: Living/Family Room: This popular set-up accommodates the widest possible range of subwoofer models, depending on the room size, playback level and décor integration. The SB-2000, SB13-Ultra, PC-2000 and PB-2000 are all excellent choices in this category for their combination of relative compactness and excellent performance across all genres of movies, music and audio content.

Dedicated Home Theater System: In this application, demanding Blu-ray movies and other high definition content are played at maximum output levels for an IMAX caliber bass experience. Maximum performance and high output (particularly at the deepest frequencies) is a top priority. This is where the larger, reference quality subwoofers come into their own, delivering a visceral and room-shaking audio experience on movie night. Depending on the room size, the following models are all excellent choices: PC-2000 or PB-2000, PC12-Plus or PB12-Plus, SB13-Ultra, PC13-Ultra or PB13-Ultra, SB16-Ultra or PB16-Ultra. The ported cylinder models offer essentially the same performance as their ported box counterparts, but with a smaller footprint, and are a great choice where floor space is tight.

2-Channel Music System: Whereas ported subwoofers shine with extreme low frequency extension and output, sealed box subwoofers are a natural choice for critical music applications because they deliver that tight, fast, detailed and articulate bass without sacrificing slam, which music lovers crave. Depending on the room size and playback level, the SB-1000, SB-2000 and SB13-Ultra will all deliver a fantastic music experience. For the ultimate in 2-channel bass, consider dual subs for true stereo bass and a more balanced soundstage.

Still Unsure About the Best Subwoofer for Your Home Audio System?

Chances are, if you’re in the market for a subwoofer, you already have loudspeakers. To help with the initial first step, SVS developed the Merlin subwoofer and speaker matching tool, which suggests the ideal subwoofer based on your specific speaker models. Merlin takes into account frequency range, output capabilities and other factors to offer an appropriate match, and with over 4,000 loudspeaker models across every brand on the market included, and recommendations generated by acoustic experts, Merlin is an excellent first step towards finding the perfect subwoofer match.

Still have subwoofer questions? We invite you to email the SVS Sound Experts at [email protected].

Syzygy SLF-850 Subwoofer

The dictionary says that Syzygy is pronounced siz-i-jee, with the emphasis on the first syllable. A syzygy is defined as an alignment of three or more celestial objects.

Listening to the heavy bass groove in George Michael’s Older, I couldn’t agree more. My Quad 2815s and a pair of the SLF850 subwoofers are blending perfectly; this is not an easy task for any subwoofer. They don’t even feel as if they are on to begin with until the “mute” button on the handy iPhone app shuts them off. Then, the soundfield produced by the Quads merely collapses. This is subwoofer perfection.

Finished in a textured, matte black 12.5-inch cube, these subwoofers get the job done without drawing attention to themselves and can be used in a downward or front-firing configuration. In my room they prove to work best in the front firing configuration, but I have no pups of the two or four-legged variety to interfere with all things audio. Should you, the down-firing option will be greatly appreciated.

The main man at Syzygy, Paul Egan is by no means a stranger to the world of high-end audio, having spent 13 years at KEF and nearly as many at API, working with Mirage and a few other well-known speaker brands. So, when the time came to create his product, he not only knew what he wanted but where to procure everything. Leveraging his past relationships, he’s been able to pack a lot more into a sub-thousand dollar subwoofer than someone starting at ground zero. Keeping things lean and mean, he’s even eschewed putting grilles on his subs to keep them all business. Discussing the background of his products, Egan makes an excellent point when he says “I’m trying to democratize good sound at a reasonable price.” At $799 each, the SLF850 is a steal.


While there are two other 8-inch subs and a 12-inch in the product mix in addition to the SLF-850 reviewed here with a 10-inch carbon fiber driver, all but the smallest model are acoustic suspension with full wireless capability. While one sub is better than none, if you’re trying to extend the LF response of your speakers, a single sub can take a little more effort to place.

Which is why I enjoy wireless subwoofers so much. No worrying about running long cables to the proper placement. The DSP optimization functionality of the SLF850 takes this a step further, because the EQ makes it easy to place and integrate the woofer. Should you want to use your SLF-850 in a traditional, wired configuration, supplying signal from either your surround sound receiver’s LFE channel or the high level outputs from your preamplifier, that is no problem.

Setup couldn’t be more painless. These compact cubes unpack quickly and Syzygy includes an excellent manual to get you rocking in no time at all. If you are proceeding in wireless mode, the tiny Bluetooth receiver/interface needs to be plugged into a variable line-level output with traditional RCA cables. Once the SLF-850 is placed where you need to put it, download the app on whatever device (iPhone or Android) you possess and run a few processes.

First, the Syzygy Sub app finds and measures your woofer(s), with your smart device about a foot from its output. Then, moving to your listening position and running another sweep adjusts the woofer to your listening environment for optimum bass performance right at the sweet spot with the “Auto EQ” function.

This will get you about 90-95% of the way home and a bit more fine tuning will bring it all to perfection. Depending on the type of main speakers you are using, the Low Pass feature allows adjustment of the crossover from 40 – 150hz.

After everything is adjusted to taste, you can control the output level from your phone, and choose “normal,” “music,” “cinema,” or “night” settings, which are more like a preset bass level control. As I don’t have neighbors close by anymore, I just let the SLF850s rip in normal mode with excellent result, regardless of program material. The mute button helps you fine tune, making it easy to cut the woofer(s) out of the loop. The better you have it all dialed in, the less you notice the woofers, until a deep bass passage – as it should be.

A versatile performer

Though Egan sent me a pair of SLF850s for this review, I started with one, because not everyone will jump off the cliff for a pair right off the bat. Three sets of speakers were used, all presenting different perspectives. My Graham LS5/9 speakers go solidly down to about 40hz, with useable output to 30, making them a good speaker that can be run full range. The KEF LS-50s are strictly a satellite, being a challenge for any subwoofer because it will have to go sufficiently high without coloration to mate well with the little monitors. Lastly, the Quad 2812s are equally tough, but for different reasons; the difference in dispersion characteristics of the ESL panel and a piston woofer (not to mention the lightning speed of the ESL panel) is usually near impossible to get right, where you aren’t hearing speakers here and woofers there. But it can be done.

The short story is that the SLF850, both singly and as a pair mates flawlessly to all three of these combinations. In single woofer mode, the SLF850 was placed just slightly off center of the main speakers (all three) back against the rear wall in front firing mode. Thanks to the fine tuning allowed by the app, there were no issues at all integrating the SLF850 into the system and for the most part, if I were in a smaller space, I could probably get along just fine with one woofer.

Moving to dual woofer mode, the little KEFs worked great with the SLF850s slightly behind and off to the side of the stands. The Grahams a bit further in both directions and with the Quads, I ended up with the woofers fairly far back, almost behind the listening couch. This made for the most seamless integration. Not only did I notice even better integration, but a pair provides wider dynamic range and better low-level linearity as well. The bulk of the listening sessions were with two woofers in place.

You don’t realize you need it till you have it

If you’ve been predisposed to thinking that you don’t need low-frequency extension, prepare to be surprised. Even with the LS5/9s, which I previously thought had plenty of bass in my 11 x 18-foot listening room, came alive with a pair of SLF850s added to the mix.

They certainly made for a lot more fun with my favorite Dubstep and hip-hop tracks as well as the entire Genesis catalog, yet even when playing music that you might not think has a ton of LF content, the soundstage in the room opens up considerably with the woofers in place. Tracking through the classic Roberta Flack & Donny Hathaway hit, “Where is the Love?” the pair of SLF850s gives both singers voices more depth and breath. Ditto listening to Miles Davis’ Tutu. Yes, the heartbeat at the beginning of Dark Side of the Moon was pretty rocking too. Again, just hit that mute button to see what you are missing.

The LS-50s took the longest to optimize (about 15 min as opposed to about 5 min with the other two), but again, once the sweet spot was located, things jelled tremendously, and these small but mighty monitors could now light up the room with heavy rock music and play considerably louder too.

Skeptical as I was that these speakers would not be able to keep pace with the Quads, (and Egan assured me that they would) they succeed brilliantly with these pesky panels. The current crop of Quads is much livelier than models past, but they are still Quads. You won’t get much enjoyment out of Metallica without the woofers, yet once in place, hard rock can now be appreciated. Grooving through TIDAL’s “favorite dance tracks of 2016” proved equally entertaining. With some serious bass happening, I’ve been able to enjoy the Quads like never before. Purists be damned.

56 pounds of sheer fun

That is if you take two. But regardless of whether you add one or two of the SLF850s to your system, fine tuned, low-frequency extension is easy and affordable. Thanks to the wireless, DSP configuration and the small form factor, I can’t think of anyone not being able to integrate at least one of these into your listening room. You’ll be glad you did. I’m adding the review samples to my Audiophile Apartment system, so you’ll be seeing and hearing more of them in reviews to come.

Our compliments to Paul Egan and the staff at Syzygy for delivering an outstanding product at a very approachable price; earning them one of our first Exceptional Value Awards for 2017.

The Syzygy SLF850 Subwoofer



Amplification        Esoteric F-07 Integrated, PrimaLuna HP Integrated

Analog Source     Soulines Kubrick Turntable/ZYX 1000 cartridge

Digital Source        Gryphon Kalliope DAC, ELAC DS-101G Server

Speakers        KEF LS-50, Graham LS5/9, Quad 2812

Cable            Cardas Iridium