REL Planar PL-1 Subwoofer Pair

Introduction

Regular readers know I’m predisposed to fast, musical subwoofers, and REL has consistently delivered in my listening room. From owning a T/5x to putting the Classic 99 (Editor’s Pick Award), a stereo pair of T/9x SEs (erm… also Editor’s Pick), and the incredible Carbon Special (Outstanding Award) through their paces, REL subwoofers have played a central role across my system setups and my ongoing Naim upgrade journey. Where the 99 offered pure musicality, the T/9x pair brought scale and impact, and the Carbon Special redefined soundstage depth.

The question now is whether a stereo pair of the compact, aesthetic REL Planar PL-1s can maintain that essential agility and musical integration.

Design

The REL Planar PL-1 is a new slimline subwoofer designed for contemporary living that can be wall-mounted or placed very near a wall.

The Planar PL-1 centres on bringing true REL speed, articulation, and musicality into what REL calls real-world living spaces where traditional subwoofers are visually intrusive or physically impractical.

Rather than trading performance for convenient dimensions or treating a compact form factor as a “lifestyle” compromise, REL engineered the PL-1 to extend seamlessly into the room. The super-thin cabinet features rounded edges, covered recessed controls, concealed cable management, and built-in wireless connectivity.

A pivotal element of REL’s approach with the PL-1 is treating the wall as an active acoustic asset rather than a compromise. Built around the concept of boundary-effect coupling, the PL-1 has a tuned 10-inch rear passive radiator in direct mechanical contact with the wall surface behind it. The PL-1 can be either mounted physically to the wall or placed on a wheeled caddy next to it.

The PL-1 passive radiator uses boundary loading to expand low-frequency extension (down to 31 Hz) and project a sense of scale, room-filling depth, and vertical height. To ensure these wall interactions do not induce cabinet smearing or colour the room, REL integrated their VIMAR (Vibration Isolation Material and Resonance Control) system (which is a bit like bespoke Sorbothane, if I’m allowed to say that, by REL) into the mounting hardware, preventing structural vibration transfer whilst preserving speed.

Technically, the PL-1 pairs dual long-throw 6.5-inch active FibreAlloy drivers with an oversized (relatively) 300W Pure Class D amplifier, providing the necessary surface area, current delivery, and low distortion without overloading compact listening spaces.

REL avoids digital signal processing in favour of their fully analogue input filters and proprietary High-Level Connection, ensuring the PL-1 receives the exact same signal fed to the main speakers. This signal can be either hard wired or received by the built-in REL Airship module.

REL says the High-Level Connection delivers effortless timing, seamless crossover integration, and unified sonic flow—what they describe as a versatile “Swiss Army Knife” for space-conscious, high-performance audio setups.

Alongside the Planar PL-1, there is a larger powered PL-2; the choice comes down mainly to room size. The PL-1 and PL-2 share the same shallow 144 mm cabinet depth and use an identical 10-inch rear passive radiator; however, they differ fundamentally in output and driver design, with the PL-1 using dual 6.5-inch active FibreAlloy drivers driven by a 300W Pure Class D amplifier. The larger PL-2 steps up to a single 8-inch FlatPiston active driver, backed by a 500W–550W Class D motor.

In terms of frequency response, the PL-1 reaches down to 31 Hz (-6 dB in room), whereas the PL-2 extends to 24 Hz.  As for which one to choose, REL says the PL-1 is tailored to smaller rooms, European flats, and stand-mounted monitors. The PL-2 is designed for open-plan layouts, larger floorstanders, and demanding setups needing effortless authority. This blog post sums it up perfectly.

Quality

The units are moderately heavy but easy to locate.  I have a pair of PL-1s on caddy wheels, so it couldn’t be easier to locate them.  The wheels attach through a few large bolts in the underside.

The unit itself has a soft feel with the REL deep lacquer finish that characterises their products.  The PL-1 has soft-touch, curved corners, with the controls recessed on top and a stylish dust cover.

Optional premium wood grille upgrades, a soft fabric grille option, and caddy wheels are also available.

Specification and Price

Performance

Review Equipment

I have a pair of black lacquered REL Planar PL-1s integrated with the upgraded Naim setup in my family’s lounge. Full details of the Naim system are at this link; basically, it’s a New Naim NSC 222 with an older NAP250 amplifier driving Acoustic Energy 320² floorstanders with Naim speaker cable.

Physically

The subwoofers are there, but they’re not there.  The family felt the enhanced sound and didn’t notice the units in the corner until I pointed them out. I have one on the Airship wireless connection, the other hard-wired.  The Airship is tuned for the PL-1 on purchase, so setup was simple.

I have a soft spike on the cart solution I have, but I gather the final retail solution has a more functional T-shaped foot.

Naim Audio with Presto Music

With an NSC222 update came a new Presto Music icon in the app; this is a new classical and jazz music streaming service that has everything, seemingly, and is terrific on first listen (the sleeve notes detail is remarkable compared to all other streaming services).  With the PL-1s in place and Presto Music, it felt like organ music was in order to get that lowest octave in the room. There’s only one place to go for this; Peter Hurford is the Don of organ music.  Bach’s Toccata & Fugue in D Minor, BWV656 (16-bit, 44.1kHz) is a favourite of mine from my earlier years.  The PL-1s get there easily, and that fantastic resonant organ ‘parp’ with the room-filling transients dominates the room.

Interestingly for me, I have the volume setting on the top of my PL-1s pretty low, in my view, at around 8 o’clock on both (from 6 o’clock).  What does this mean?  Three things: firstly, my eardrums are still in good shape from the added pressure in the room; secondly, they are working so well using the wall proximity; and, more importantly, the music I’m listening to is the star of the show; the RELs are just putting it in a frame.

At this point, I can put on bass-heavy music like Beyoncé’s Partition or Newton Faulkner’s Teardrop, and of course I can play Blade Runner 2049, but it is in detailed music where you can add weight and feel.

The expanded soundstage is key to a fast subwoofer like this, and pop tracks like Myles Smith’s Stargazing (Qobuz 24-bit, 44.1kHz) and Noah Kahan’s Stick Season (Qobuz 24-bit, 96kHz) are lifted onto a different audio plane. Sabrina Carpenter’s Espresso (Qobuz 24-bit, 96kHz) does the same as does It Stoned Me (Qobuz 24-bit, 96kHz) by Van Morrison.  It really is joyful.

Electronic music really enjoys this added weight in the room; for example, Peter Hook’s bass in Age of Consent (Power, Corruption and Lies, Qobuz 24-bit, 96kHz) and Kraftwerk’s The Model (Qobuz 24-bit, 44.1kHz) come over smoothly.

A Single PL-1

So far, I’ve been using both RELs, but a single PL-1 does a decent enough job, though it takes a couple of additional volume clicks to get the same effect. I guess the ease of having the pair is what makes this experience such a gift.

Thoughts

Not for the first time, or the last, I imagine, I will suggest a subwoofer is the single most effective upgrade you can make to a system.  This reflects the room largely, but also the system in question.  As you read in the Naim Upgrade Journey piece, I said:

Of all the upgrades I have made (to the Naim Classic system), this one is possibly the most effective.

This remains true with the PL-1; as with other RELs out there, they are fast and musical. This one is no exception.

What Three Words

Pace – Ambition – Execution*

*with a nod to Clive Woodward, England Rugby World Cup-winning coach

Overall

The stereo pair of REL PL-1s effortlessly elevates the listening experience, providing scale and speed without dominating the presentation. Paired with the Naim NSC222 and Presto Music, they deliver deep, resonant, room-filling transients on complex classical organ pieces, even at low gain settings. Beyond handling heavy bass, their true strength lies in soundstage expansion—lifting acoustic, pop, and electronic tracks into a higher plane of weight, detail, and musical texture. While a single PL-1 performs admirably with a minor volume adjustment, a stereo pair provides an effortless, joyful natural alignment that simply frames the music perfectly.

REL Playlists Used

Playlists used in this review, with a few others for good measure.

Love 

• Effortless
• Fast bass
• Set and forget
• Ease of stereo pairing

Like 

• Slim fitting
• Ideal if you’re stuffing a subwoofer in the corner anyway

Wish

• For nothing more from REL