REL Subwoofers: Finishing The Work Your Speakers Started

“I could not imagine reading a book where the last few pages of every chapter were missing. So why do we accept this from our music? Without a sub this is exactly what you get.”

How REL Made Subwoofers Essential

Few companies can say they changed the industry landscape for the audio component they are famous for making. However, REL is one of the few that can. I remember a time 25 to 30 years ago when subwoofers were rare in two channel systems—even frowned upon. Now they are in almost every system, and in stereo pairs! In those past decades, only one thing really changed in the world of subwoofers, and that was REL. With a relentless pursuit of innovation and constantly educating listeners through articles, videos, and in-person events, REL has become trusted as the authority in subwoofers in the audio industry.

A subwoofer is much more than the woof, the bump, the rattle. It's about finishing a thought, completing a picture, finishing the song, or most accurately, finishing your audio system.

The range of human hearing is considered to be 20Hz - 20kHz, and this is also the basis for measuring frequency ranges in audio. Most speakers on the market aren’t truly full range—even if their specs claim they reach 30-40Hz. It's incredibly rare to find a passive speaker that is able to reproduce the full frequency range. There are some ultra-high-end speakers where it is possible, such as the Paradigm Persona 9h, which has 1400 watts of amplification built in just for the woofers. 

In reality, few passive speakers can reproduce sub-bass frequencies effectively, and even fewer can pressurize a room the way a subwoofer can. This means there is a whole frequency band, an entire octave of music you are missing. In some instances, you’re missing entire instruments. I could not imagine reading a book where the last few pages of every chapter were missing. Why do we accept this from our music? Without a subwoofer in your system, this is exactly what you get.  

Part of the issue is that producing true and deep bass takes significant power. To experience true sub-bass (20Hz - 70Hz), most listeners will need a dedicated subwoofer. While standard speakers generally reproduce bass down to 80 - 40Hz (depending on the design), a subwoofer steps in to complete the job. It supports what your speakers are putting out in those lower ranges, ensuring nothing is left unheard or unfelt. REL subwoofers are designed for exactly that purpose—to finish out your speakers and your system.

For many years, subwoofers were considered optional in two-channel systems—an afterthought at best. But as our understanding of low frequencies has evolved, so has the role of the subwoofer. REL, under the guidance of lead designer John Hunter, has played a critical role in that evolution. With a tireless commitment to both innovation and education, REL has reshaped the conversation around subwoofers. Resources like their REL Pairing Guide and a deep library of educational videos have empowered listeners to integrate subwoofers not just effectively—but artfully—into their systems. 

Today, the idea that a subwoofer is essential to completing a full-range system is no longer controversial; it’s expected. REL has helped redefine the sub not as a mere add-on, but as the missing piece that allows your speakers to fulfill their full potential. So how did they get here? Let’s take a look at REL’s history—and more importantly, what makes their approach so unique.

What Sets REL Subwoofers Apart? Company History and Commitment to Audio Excellence.

REL’s story begins with a commitment to doing things differently—and doing them right. From the outset, their designs have emphasized quality, simplicity, and innovation. One of REL’s most distinctive choices was their focus on using a high-level input; rather than taking a signal from the preamp, REL subwoofers connect directly to the speaker terminals of your amplifier. This approach allows the sub to receive the exact same signal and timing as your main speakers, ensuring seamless integration and a more natural, musical result. More on that later.

When founder Edmund Lord established REL Acoustics in 1990, subwoofers were mostly created as an afterthought by speaker manufacturers. REL set out to change that. After working on several successful sub designs centered around using the “high-level” connection rather than the typical RCA connection, REL found it dramatically improved a subwoofer's ability to blend seamlessly at the crossover point with your speakers.

A major turning point came in 2005, when REL brought on lead designer John Hunter. Under his leadership, REL began developing their more modern design approach while experimenting with driver placement, implementing the PerfectFilter™ and the LimitLess Limiter™, and refining the speed and musicality of their subwoofers. What has emerged is a new generation of subwoofers that are known to be incredibly fast, incredibly musical, and shockingly easy to integrate. The company has since gone on to create some of the most musical and innovative subwoofers in the world, and become one of the most respected names in audio.

How REL Subwoofers Enhance Music Listening: Unique Engineering and Design Philosophy

A subwoofer should complement your system, not be the focal point. Everything around the design of a REL subwoofer is aimed at that goal, becoming part of a complete system. So how does REL go about achieving this goal?

Most subwoofers on the market today rely on a low-level input from your preamp via a standard RCA cable. While this works just fine, what you’re really getting is the signal your preamp is sending to the amplifier—which can introduce a slight loss in timing or coherence. Think of it like this, with this method, you have a signal going directly to your subwoofer from the preamp. The preamp also sends a signal to the amplifier, whether integrated or not, which then sends the signal to the speakers. There is an extra step between when the speakers see the signal and when your subwoofer does. This allows for slight timing issues, and also adds in another component which can change the sound and influence the character of the signal.

REL’s connection philosophy is built around this simple concept: that a subwoofer is meant to act as an extension of your speakers, not as a separate boom box. To achieve this, REL focuses on preserving timing, grouping, coherence and musicality. REL’s preferred method is their high-level input, which takes a direct feed from your amplifier’s speaker terminals. This method delivers the same signal and timing as your main speakers receive, resulting in a seamless, unified sound.

Their proprietary speakON high-level connection makes this even easier, not to mention fast and secure. This is a large part of why REL subwoofers blend so seamlessly into two channel systems. For added flexibility, REL also offers wireless options like the AirShip II and HT-Air MK II modules. These systems deliver low-latency, high-fidelity signal transmission without the clutter of cables, making it easier than ever to place your subwoofer exactly where it performs best.

The result is a tighter, more seamless handoff between your speakers and the subwoofer. Think of it like the difference between a gold medal Olympic team passing the baton, versus you and your friends at 40 trying to do the same thing. It simply integrates better, letting the subwoofer disappear into the system rather than sounding like a separate bass box.

Beyond connection methods, REL incorporates proprietary technologies like the PerfectFilter™ to extend performance in the lowest octaves. In most subwoofers, frequencies below 50Hz tend to roll off rapidly due to physical limitations in cabinet size and driver design. Counteracting this with larger enclosures would often require doubling the cabinet volume—something impractical for most systems. That’s where REL’s PerfectFilter™ comes into play. According to John Hunter, the filter does most of its “magic” between 40Hz and 25Hz, gently boosting and shaping output in this critical sub-bass region. Its purpose is to restore low-frequency extension and balance, helping the subwoofer deliver a flatter, more natural response that better integrates with your main speakers.

This allows REL subs to reach incredible depths and low-end extension while keeping a natural sound, and an enclosure that does not overtake the room! These innovations, combined with their state-of-the-art cabinet design, help the sub stay fast, articulate, and expressive—even when reaching down to the lowest frequencies. The result isn’t just more bass—it's a deeper connection to the music.

All this comes before we even talk about the actual woofer drivers! REL subwoofers often utilize a combination of passive radiators and front-firing drivers to achieve deep, musical bass with clarity and speed. Depending on the model and series, they may utilize a front-firing active driver that produces direct sound waves, delivering precise low-frequency impact. The passive radiator enhances low-end extension without the need for a larger enclosure. This design allows REL subs to maintain compact dimensions while offering rich, room-filling bass. 

The synergy between the two components ensures both power and finesse, ideal for both music and home theater setups. Depending on the model, REL subwoofers use a variety of advanced driver materials—including FibreAlloy™ paper-aluminum composites, CarbonGlas™, pure carbon fiber, carbon-reinforced cones, continuous cast alloy, and rubber surrounds—all of which optimize rigidity, speed, and bass articulation.

You now have all the elements for a true subwoofer, not just a boombox. Let's talk more about how a REL can affect two channel listening, and home theatre alike. 

REL For Two Channel Systems:

With their signature technologies and design elements, REL subwoofers do more than just add bass. They coax it out of the recording, and bring it out in a way that enhances your entire listening experience. By extending the low end with speed and control, their subs improve tonal balance, clarity, and emotional impact across the entire frequency spectrum. With their high-level connection and fast response, REL subs integrate seamlessly into two-channel systems, adding body and weight without muddying the midrange or distracting from the main speakers. Many recordings are immensely supported by the bass and sub bass, and sound off or completely fall apart without sub bass reproduction. One example would be “Angel”  from Massive Attack. In this track, the bassline is incredibly immersive and helps keep the track moving. Without sub bass, you the bass actually sounds like it is cutting in and out of the track, since the speaker can only produce parts of the instrument, but not the lowest notes. There are some recordings such as “Thanks to You” from Boz Scaggs, where there are entire instruments operating in sub bass, reaching as low as 22hz. Without a subwoofer, you would be unable to reproduce the entire song. 

A big part of how your subs will sound in a stereo setup is in the placement. Finding the right place for your sub can be frustrating, and a challenge. REL makes it a lot easier. Their subs thrive in corners, which naturally reinforce low frequencies. From there, a few simple adjustments to gain, crossover, and phase can lock in performance so tightly, you’ll forget the sub is even there—until you turn it off and suddenly everything sounds flat. Proper setup brings not just more bass, but better bass—tight, musical, and perfectly timed. For many listeners, having this be an easy process makes it much more enjoyable to use a subwoofer all around.

When properly integrated, REL subwoofers don’t just reinforce the bass—they absolutely transform the soundstage. You’ll hear more air around instruments, deeper front-to-back layering, and a sense of the room opening up, providing a more immersive and three-dimensional listening experience. Beyond REL’s unique aspects and how well their subs integrate, another factor is how many of their subwoofers you add to your system. 

Stereo Pairs and Six Packs: Expanding the REL Experience

You don’t buy just one speaker—so why buy just one subwoofer? Over the past decade, stereo subwoofers have become the new normal, and REL has led the charge in making them accessible and effective. Their signature high-level connection makes stereo integration seamless, while also helping pressurize the room more evenly, making it easy to dial in the ideal crossover point.

But REL didn’t stop there. Their S Series and Reference Series are designed to scale—to go beyond the pair. You can build a full line array of subwoofers, commonly referred to as a “six-pack”—three subwoofers supporting each channel. It’s an approach built on precision, realism, and immersion.

A common myth suggests subwoofer placement doesn’t matter because bass is “felt, not heard.” While there’s some truth in that, this thinking ignores one major detail: you’re still listening to stereo content. Relying on a single sub to reproduce the full bass spectrum of both channels compromises the intent of the recording—and the impact of your system.

Think about how much effort goes into getting your main speakers positioned just right. Push one too close to the back wall, and it gets boomy; pull it out, and the sound opens up. Now imagine turning that speaker around and expecting it to reproduce only the low frequencies—how far would you have to pull it into the room before the bass sounds right?

Room modes—standing waves that amplify or cancel out specific bass frequencies—are a major challenge when using a single sub. These powerful frequencies tend to gather in certain areas of a room while disappearing in others. Tuning one subwoofer to work in your space can be a frustrating—and never-ending—task.

A stereo pair of REL subs offers a simpler, more elegant solution. One sub handles only the left channel’s bass, the other the right. Integration becomes more intuitive. You’re now tailoring volume and crossover to match your speakers, your room, and your listening position—not compromising to make one sub work for the entire space.

This approach also improves imaging. It helps the subwoofers “disappear” into the system. With a single sub, there’s often a moment in a song where it gives itself away—a bloated vocal, a rattling object, or a note that feels disconnected from the music. That’s because it’s being asked to handle content from all over the soundstage—left, right, and center. That’s a big ask.

REL’s John Hunter has long championed the use of stereo subs, and today, it’s hard to imagine serious two-channel listening without them. For many—including myself—it’s the difference between casual enjoyment and a deeply emotional, immersive experience.

And then there’s the six-pack.

REL’s six-pack system takes things to a whole new level—three subs per channel, stacked vertically in a line array. While it may seem extreme, it’s rooted in acoustic realism. Bass doesn’t only happen at your feet. Sub-bass information plays a critical role in how we perceive depth, space, and timing. This is especially true in high-end two-channel systems aiming to recreate a live performance or studio environment.

Vocals are a perfect example. A voice over a phone speaker has no weight. In a real room, from a few feet away, a voice carries depth. Whispered in your ear, it’s pressurized and full. That “weight” is largely communicated by low frequencies—and by how they interact with your room.

If your system can’t produce those supporting frequencies accurately and evenly, you lose realism. You lose the sense of where the sound is coming from—how close or far, how large or small the space is. Ever heard a recording where the singer sounds like they’re in a hallway? Then another where they’re right up on the mic? That’s not just reverb. It’s bass cues telling your ears the story of the space.

REL’s stereo and six-pack solutions aren’t about more bass—they’re about better bass. More articulate, more spatially aware, and more emotionally engaging. This is the ultimate goal when adding subwoofers to any two channel system, but what about those who are looking for subwoofers that can handle more than just music? 

REL Subwoofers in Home Theater Setups

Home theater has become quite common over the years, and this is where many folks have experience with subwoofers. In most home theater settings, the listener is using a processor, preamp, or TV that is sending the signal to the subwoofer through the LFE (Low-Frequency Effects) or .1 channel via an RCA connection. This channel is actually a separate digital track encoded in movies and TV. This is great for movies, but this track is not present on music. Using the .1 channel also makes utilizing room correction much more accessible. The .1 channel is designed for low-frequency content, making it ideal for room correction software to focus on the bass frequencies that are most affected by room acoustics.

With that in mind, for home theater, you typically want explosiveness—the ability to make a distinct, loud, sustained impact. Musicality is not typically something that is in mind, which leads to some subtle design differences. The REL HT Series is just that, designed for the job and built for the boom! 

Understanding REL’s Subwoofer Series:

Over the years, REL has expanded its technology into several different series to offer subwoofer solutions for any room, with any speaker, in any scenario. Whether you are exploring adding a subwoofer for a small space, or if budget is no object and you seek the best, most realistic soundstage possible, REL has you covered. Let's explore the different subwoofer series REL has to offer. 

Series T/x - Small but Mighty, and Remarkably Fast

The “T Serie” of subwoofers is great for almost any room, speaker pairing, and budget. With a best in subwoofer class A/B amplifier, and REL’s signature high level connection, these subs will pair with almost any speaker. From a small desktop setting with the T Zero, all the way to a larger space with the T/9x, the T series has a sub to support making your system sound massive.

• T/5x – Compact, sealed, and fast. Ideal for smaller rooms and disappearing-act bass.

        ( 8” driver / 125W / Low 32Hz )

• T/7x – The sweet spot of size, speed, and output. Balanced performance for most systems. (8” active + 10” passive / 200W / Low 30Hz )
• T/9x – Largest and most powerful in the T/x line. Serious depth and scale without sacrificing control. (10” active + 12” passive / 300W / Low 27Hz )

The subwoofers can come in a stereo pair. If space permits, this is highly recommended. Many times you can get better performance by stepping down a model but getting stereo pairs rather than a single. For example, rather than one T/9x, many listeners elect to get two T/7x subs.

REL Classic Series - Vintage Looks, REL Speed

The Classic Series fills a nice hole in the REL catalog. For many years, subwoofers traditionally used a single downward-facing driver. REL revisits these designs with a modern engineering touch. With a classically simple look, and gorgeous walnut veneer, these subwoofers blend into any environment with ease. Their style is where the retro part stops. These subs are fast, and I mean REL fast.

• Classic 98 – Vintage-inspired design meets modern performance. Smooth, musical bass with a natural, relaxed feel. (10” driver / 300W / Low 27Hz )
• Classic 99 – Retro elegance with added authority. Deeper extension and more drive for larger spaces or systems needing extra weight. (12” driver / 450W / Low 24Hz )

Both models have all the speed and depth REL has come to be known for, but with a little more robust sound. The idea was to sonically and aesthetically blend with classic speaker designs, as well as modern speakers. You can integrate one of these seamlessly into any system, or use them in pairs.

Series S - Where the Line Between Audio and Life Begin to Blur

For those who want to reach into the sonic depths of every recording, REL has the S Series. Some listeners have an insatiable need for bass, some crave a sub that can keep up, and others just want to know they have the best. The S Series steps up REL’s game with an incredible class D amplifier, improved drivers, and an even more refined cabinet design. These subwoofers are compact, powerful, and go low. You may lose their physical placement in the room, but their presence will be undeniable.

• S/510 – Tight, refined, and lightning-fast. Perfect for high-resolution systems needing speed and nuance. (10” active + 12” passive / 500W / Low 20Hz)
• S/812 – Bigger, bolder, deeper. Built for full-range setups craving scale, slam, and composure. (12” active + 12” passive / 800W / Low 19Hz)
• Carbon Special – Statement performance. Carbon fiber driver, passive carbon radiator, and NextGen5 amp deliver reference-level detail, speed, and soul. (12” carbon fiber active + 12” carbon fiber passive / 1,000W / Low 19Hz)

These subwoofers can of course also be run in a stereo pair, this is highly recommended. However, If you have the space and budget, this line is where REL introduces the ability to link multiple subs in a stack, leading to four or six packs of subwoofers. You can have as many as three S Series subs stacked in a line array and connected via the proprietary linking cable for a complete system that will have you in awe for days.

REL Reference Series - True Class Through and Through

There are systems out there that, shall we say, were not designed with a budget in mind. The best of the best. Ultra-high-end speakers still need a sub, and REL has the answer: the Reference Series. These subs are meant for systems that have more to reveal than even the stellar S Series can keep up with—systems built to reproduce every note, sound, feeling, and emotion in a recording.

• No. 31 – Ultra-high-resolution bass. A 12” carbon fiber driver and 1,000W amp deliver transparent, musical, and deeply authoritative performance. (12” carbon fiber driver / 1,000W / Low 17Hz )
• No.32 – Monumental scale and lightning-fast articulation. Built for the world’s finest systems. (15” carbon fiber driver / 1,000W / Low 15Hz / Low 15Hz

HT Series - Home Theater from the Depths

The REL HT series is honed in on ensuring your movies make an impact on you. Whether they’re supporting vocals or the bellowing depths of Mordor in The Lord of the Rings, the HT subwoofers are designed to make sure they can not only reach the bottom, but to go the distance with your movie collection.

• HT/1003 MKII – Compact thunder. Tight, punchy bass for smaller spaces and media rooms. (10” driver / 300W / 24Hz )
• HT/1205 MKII – Big impact, small footprint. Ideal balance of size, power, and performance. (12” driver / 500W / Low 22Hz )
• HT/1510 Predator MKII – Cinematic power. Room-shaking energy with depth and authority. (15” driver / 1,000W / Low 20Hz )

These subwoofers can be connected as a single, in pairs or stacked in line arrays.

REL Subwoofer Accessories and Enhancements

For added flexibility, REL’s AirShip II and HT-Air MK II wireless adapters let you place your sub wherever it performs best without sacrificing signal quality. To maximize performance, use high-quality cables to ensure the cleanest, most accurate signal transfer possible. You don't have to spend thousands either, the REL Bassline Blue is a really well designed cable, and there are other options from Kimber and Audience.

These are some of the incredible solutions that REL has employed to make sure you have the best options available, but let's talk about why you would choose a REL over other subs in the first place.

REL Subwoofers vs. Competitors: Why Choose REL in a Sea of Options? 

Now that subs are finding their way into more systems, the options seem to be mounting. Subwoofers are no longer an afterthought, and there are tons of incredible woofers on the market today to choose from. What still sets REL apart? 

There are an incredible amount of options available, and quite a few I've tried, from the famous Bob Carver Sunfire back in the early days of subwoofers, to the popular SVS subwoofers of today. Many of these subwoofers are great and offer incredible performance in most aspects. I usually find one thing or another seems to be out of focus. Either they sound a little boomy, or they are a little tougher to integrate. What tends to happen to me, and I would say for many listeners, is that even when you get that sub dialed in, you are never really done. You will continually second guess, and fiddle with crossover settings, and placement until you go crazy.  

Like many listeners, when finally I got a REL in my system, I stopped tweaking and just started listening. The ease of integrating a REL alone makes the whole experience much more enjoyable. Past that, they sound right and disappear into the image. After they are integrated and the crossover is blended with your speakers, you are done. I go months and months without even thinking about mine.

I attribute this to not only the high level connection providing the same signal as the speaker, but the speed of the sub overall. Many subs can sound a little sluggish, like they are half a step behind your speakers. This causes issues, mainly by making your subs stick out in the soundstage. These subs don't blend with your speakers quite as well, and you hear separate speakers and a subwoofer, not one cohesive sound. Your system has not been completed, just added to. 

REL subwoofers are definitely the king of subwoofers, with incredible designs that can be relied on for decades to come. Fast, easy to integrate, and soul moving bass—that's the name of the game, and REL is winning.

Over the years, subwoofers have become fairly common for two channel listening, and REL has had an incredible influence on that becoming the case. Whether through relentless pursuit of design perfection, or simply supplying constant education to the audio community, REL continues to lead the pack in spreading the use of subwoofers in audio. If you don't already have a sub, I would highly recommend that you complete your system and look into adding a REL. Actually, if you don't already have one, go ahead and get two!

FAQs (Frequently Asked Questions)

How do I Tune the Crossover on my REL? - Quick Tips

• Start with the crossover at 10 o’clock (15 clicks from minimum) and High/Low Level at 10 o’clock.
• Set phase orientation (0 or 180 degrees) for the fullest bass response.
• Adjust crossover to achieve a smooth transition, avoiding boominess or harshness—aim for a natural blend with your speakers.
• Fine-tune High/Low Level control to match the REL’s volume with your mains for balanced sound.
• Listen carefully and make small adjustments to fine-tune for clarity and balance.
• Consider room acoustics, corner placement, and speaker orientation for optimal performance.
• Be patient—tuning takes time and should be done by ear for the best result.

Are REL subwoofers good for both music and movies?

Yes, even if not using a sub from the dedicated HT line, rel subs are incredibly capable of utilizing them for movies and music. In addition to the Hi Level Connection, Rel subs come equipped with the LFE/.1 channel utilized for film and TV.

How do I connect a REL subwoofer to my AV receiver?

You can utilize the LFE or .1 input if they are the only available inputs, or you are using the sub for movies and require the .1 digital track from film and TV. However using the high level connection is preferable for two channel listening. For added flexibility, REL’s AirShip II and HT-Air MK II wireless adapters let you place your sub wherever it performs best.

Is a high-level connection better than LFE?

Having the high level connection allows the sub to “speak the same language” as your speakers, because it takes its signal directly from the speaker terminals on your amplifier. Allowing for your amplifier to dictate the signal and voicing for both your speakers and sub, helping with speed, musicality, and integration.

What’s the best REL subwoofer for small rooms?

The REL T Zero and T/5 are both designed specifically with smaller spaces in mind, however if you are not sure you can reach out to one of our hi fi guides, or use the speaker pairing tool on REL’s website.