- Introducing the Rel Acoustics Planar PL1
- Key specifications
- Introducing the Rel Acoustics Planar PL2
- Key specifications
- What accessories are included?
- Test conditions
- Unconventional format, very appealing finish
- Connectors
- Two personalities, two ways of exploring bass
- REL Planar PL1 compared to the REL HT/1510 Predator
- Rel Planar PL2 compared to the Rel Acoustics S/550
- Who are the Rel Acoustics Planar PL1 and PL2 subwoofers designed for?
What we liked
- The very natural integration of the bass
- The precision of the PL1 and the fullness of the PL2
- The slim design, ideal for wall mounting
- The elegant lacquer finish
- The included AirShip Direct wireless system, which is easy to use
We would have liked
- Magnetically attached grilles
- A finish that’s less prone to smudges and dust
- Greater extension in the extreme low frequencies for the PL1
Our expert’s opinion
The REL Acoustics Planar PL1 and PL2 offer a compelling solution to an often-tricky problem: integrating a high-performance subwoofer without sacrificing a significant amount of available space in the room. Their flat design really comes into its own when placed against a wall—provided this placement is strictly adhered to. Our tests clearly showed that when placed away from the wall, the Planar subwoofers lose much of their appeal; when positioned correctly, they immediately deliver greater depth and impact.
The PL1 impresses above all with its fast, tight bass that blends exceptionally well with the speakers. Its frequency response is somewhat limited, making it better suited for rooms of moderate size. The PL2 takes things to the next level with greater depth, richness, and presence, without sacrificing that excellent integration.
The included AirShip Direct system is another major advantage and makes installation much easier. The grille mounting system is one of the few criticisms we have: once the grilles are removed, the tabs remain visible, particularly on the white finish. The lacquered surface, while very elegant, also shows marks easily, especially the black version.
With prices of €2,399 for the PL1 and €3,599 for the PL2, these two subwoofers clearly occupy the high-end segment. This positioning stems as much from the quality of the finish and the attention to detail in the design as it does from the particularly sophisticated acoustic concept, which takes full advantage of the wall while ensuring seamless integration with your speakers.
Compared to conventional subwoofers offered at a similar price, the Planar models don’t necessarily aim for the most spectacular bass response. Their true strength lies elsewhere: delivering convincing, well-integrated bass that blends much more easily into a living room.
A subwoofer capable of boosting the bass without taking up a lot of space in the middle of the living room? With the Planar PL1 and PL2, REL Acoustics has radically changed its approach to design. Their cabinets, which are only 14.4 cm deep, are ideally positioned against a wall or mounted directly on it, using the wall’s surface to radiate low frequencies. High-level connection, AirShip Direct wireless transmission, and two performance levels round out this unconventional approach. But do the REL Planar subwoofers succeed in balancing discretion, depth, and musical integration?
Introducing the Rel Acoustics Planar PL1
The REL Acoustics Planar PL1 is an active subwoofer ideal for rooms ranging from 10 to 20 m². It effectively complements a soundbar, a pair of bookshelf speakers, or small floorstanding speakers, whether active or passive. This model is specifically designed to be placed right next to a wall or mounted directly on it. Its cabinet is only 14.4 cm deep and takes advantage of the coupling effect with the wall to extend the bass response while minimizing the space it takes up in the room. It measures 52 cm wide by 49 cm high and weighs 18.9 kg. The REL PL1 subwoofer is available in two finishes: black lacquer and white lacquer.
Its front panel features two 6.5″ active drivers with FibreAlloy cones and long-throw designs. They work alongside a 10″ rear passive radiator, also featuring a FibreAlloy cone. The system is powered by a Class D amplifier delivering 300 watts RMS. The manufacturer claims a frequency response extending down to 31 Hz at -6 dB in the room, a configuration designed to provide more depth and extension to the main speakers.
The PL1 features a Neutrik Speakon high-level input, an RCA low-level input, and an LFE input. The cutoff frequency is adjustable from 30 to 120 Hz, and the phase can be switched between 0° and 180° to precisely tailor its performance to the speakers and the room.
Key specifications
- 2 active 6.5″ drivers
- 10″ passive radiator
- 300 watts RMS class D amplification
- Bass response down to 31 Hz (-6 dB)
- Adjustable cutoff frequency from 30 to 120 Hz
- Speakon high-level inputs, RCA low-level inputs, and RCA LFE inputs
Introducing the Rel Acoustics Planar PL2
The REL Acoustics Planar PL2 builds on the design of the PL1 with a slim cabinet designed to be placed as close as possible to a wall or mounted directly on it. It retains a depth of just 14.4 cm but features a wider profile, measuring 65 cm wide by 48 cm high. It weighs 20.25 kg.
The main difference lies in the driver system. While the PL1 uses two 6.5″ active drivers, the PL2 features a single 8″ long-throw FlatPiston driver. The latter is paired with the same 10″ rear passive radiator featuring a FibreAlloy cone. The Class D amplifier also delivers more power, increasing from 300 watts RMS on the PL1 to 550 watts RMS on the PL2.
This configuration allows the PL2 to go deeper, with a specified response down to 24 Hz at -6 dB in the room, compared to 31 Hz for the PL1. It should therefore provide greater extension in the sub-bass range and superior dynamic headroom. The connectors remain the same, with high-level Speakon inputs, low-level RCA inputs, and an RCA LFE input.
It is ideally suited for use with a 5.0 speaker system, a soundbar with a subwoofer output, or a pair of latest-generation wireless speakers in a living room that’s 25 m² or larger.
Key specifications
- 8″ FlatPiston driver
- 10″ passive radiator
- 550 watts RMS class D amplification
- Bass response down to 24 Hz (-6 dB)
- Adjustable cutoff frequency from 30 to 120 Hz
- Speakon high-level inputs, RCA low-level inputs, and RCA LFE inputs
What accessories are included?
The two REL Acoustics Planar subwoofers come with a fabric acoustic grille, an angled power cable, and a cover to protect the control panel. The package also includes everything needed for wall mounting, including mounting rails, screws, dowels, a drilling template, and two hex keys.
REL also offers the AirShip Direct wireless system. Its receiver is built directly into each subwoofer, while the external transmitter comes with its own power supply, a 1.5-meter Neutrik Speakon high-level cable, and two RCA cables. This solution makes it easy to mount the subwoofer on the wall while avoiding the need to run a long audio cable to its location. Simply connect the transmitter to the SUB output or the speaker terminals on the amplifier or soundbar, and it will transmit the signal to the subwoofer.
Optionally, you can purchase a wooden grille and a stand with casters separately if you do not want to wall-mount the subwoofer.
📝 Tips from the expert
The REL Acoustics Planar PL1 and PL2 should be placed as close to a wall as possible. Users have two options: mounting the speaker directly on the wall using the included bracket, or installing it on the optional rolling stand. In the latter case, it is best to keep the subwoofer parallel to the wall and minimize the distance between them as much as possible.
This proximity plays a key role in how the PL1 and PL2 subwoofers function. REL takes advantage of boundary effect coupling: the wall helps build up pressure in the room and enhances the bass extension.
Our tests clearly confirmed this. When placed away from the wall, both subwoofers delivered a bass response that was significantly less impressive, with less depth and impact. Once moved closer to the wall, the bass immediately gained clarity, amplitude, and intensity. Proper positioning is therefore not merely a minor installation detail but an essential requirement for obtaining the best possible performance from these REL 2026 subwoofers.
Test conditions
For this test, I paired the two REL Acoustics subwoofers with an Atoll IN200SE amplifier driving a pair of Elipson Prestige Facet 8B bookshelf speakers. I opted for a high-level connection using the supplied Speakon cable: the red and yellow wires were connected to the positive terminals of the amp’s two channels, while the black wire was connected to one of the negative terminals. A Rega P3 turntable equipped with a Grado Gold 3 cartridge served as the source for the various listening sessions.
Before beginning the listening sessions, I set the subwoofer’s high-pass cutoff frequency to around 55 to 60 Hz, slightly above the advertised lower limit of 47 Hz for the Elipson Prestige Facet 8B. This overlap allows the subwoofer to gradually take over without creating a break in the low frequencies.
Adjusting the level then requires a few fine-tuning adjustments by ear using the Hi-Level knob. The goal is to achieve a smooth transition—without dips or peaks—until the subwoofer becomes acoustically inaudible, resulting in low frequencies that seem to simply reinforce those of the main speakers.
📝 Note from the expert
Why is a high-level connection important in hi-fi?
With a high-level connection, the subwoofer connects directly to the amplifier’s speaker outputs. It therefore receives the same signal as the one sent to the main speakers. Because its input has a very high impedance, it places virtually no load on the amplifier.
The main benefit is in the sound. The subwoofer receives a signal that has already passed through the amplifier stage, retaining its dynamics and sonic signature. It can therefore complement the speakers in the ultra-low frequencies while maintaining greater consistency with their sound reproduction. Once the volume and cutoff frequency are properly adjusted, the subwoofer becomes more unobtrusive: the bass seems to be a natural extension of the speakers’ low frequencies, rather than coming from a separate unit.
That is why REL recommends this method for hi-fi use, via a Neutrik Speakon connection using the cable provided, which should be connected to the amplifier’s speaker terminals.
Unconventional format, very appealing finish
The REL Acoustics Planar PL1 and PL2 have a particularly attractive finish. The glossy lacquer gives them a very polished look, but there is a downside: the surface shows marks easily. The black finish, in particular, shows dust and fingerprints.
REL also offers optional wooden grilles, which add a warmer touch than the traditional fabric acoustic covers that come standard. Their mounting system is less impressive. The grilles are secured with tabs rather than magnets, which leaves the holes visible when you want to use the drivers without the grilles. Installing or removing the grille is also somewhat inconvenient when the subwoofer is on its rolling cart, as one of the wheels blocks access.
On the other hand, the very flat design makes it easy to place the speaker against a wall, in line with how Planar speakers work. However, it still takes up a fair amount of space, especially with the optional wheel stand, which moves the sub slightly away from the wall and increases its footprint.
Another well-thought-out detail: the control panel is located on top and is concealed beneath a removable cover. This keeps the phase, high-level, LFE level, and cutoff frequency controls easily accessible without detracting from the overall aesthetic.
Connectors
The REL Acoustics Planar PL1 and PL2 feature the brand’s signature connectivity options. A Neutrik Speakon high-level input allows you to tap the signal directly from the amplifier’s speaker outputs. An RCA low-level input and an RCA LFE input round out the wired connections.
The main advantage, however, comes from the built-in REL AirShip Direct wireless system. The receiver mounts directly onto the subwoofer cabinet, while the included transmitter connects to the amplifier via Speakon for high-level input, via RCA for low-level input, or to an LFE output. The transmitter also features a balanced XLR LFE input. REL provides the power supply, the high-level cable, and the two RCA cables needed for setup.
In practice, setup is particularly simple. After turning on the transmitter and activating the receiver on the subwoofer, simply press the “Pair” buttons to establish the connection in just a few seconds. This wireless connection is especially useful with subwoofers designed to be placed against a wall, since it eliminates the need to run a long audio cable to their location.
Two personalities, two ways of exploring bass
To evaluate the two Planar subwoofers, I mainly alternated between Amy Winehouse’s Back to Black, The Beatles’ Abbey Road, and Led Zeppelin II. These three albums feature very different production styles, making them ideal for assessing the impact, control and integration of the bass.
REL Acoustics Planar PL1
The Planar PL1 prioritizes precision above all else. On Amy Winehouse’s “You Know I’m No Good,” it effectively reinforced the rhythm section without weighing down the sound. The bass remained tight, punchy, and well-defined, with enough impact to add substance to the listening experience while maintaining overall balance.
The same was true for the Beatles’ “Come Together ”: the bass line had more presence and clarity, without ever sounding disconnected from the Elipson Prestige Facet 8B speakers. The subwoofer blended seamlessly into the soundstage and, above all, filled in what the speakers lacked in the lower end of the spectrum.
On Led Zeppelin’s “Whole Lotta Love,” the PL1 effectively highlighted the energy of the drums and gave the track more depth. However, it maintained a somewhat tight response in the bass. A few extra hertz in the extreme low frequency range would have added more depth and breadth during the most complex parts of the track.
In my opinion, this sound signature will be particularly well-suited to rooms measuring about 15 to 20 m², where the PL1 combines impact, responsiveness, and easy integration.
REL Acoustics Planar PL2
Upgrading to the Planar PL2 significantly changed the scale of the soundstage. The bass gained depth, volume, and presence, with a slightly rounder tone than that of the PL1.
With “Back to Black,” the sound became denser in the low end of the spectrum. The subwoofer provided more body without masking the vocals or unnecessarily weighing down the accompaniment. On The Beatles’ “I Want You (She’s So Heavy),” the PL2 delivered a fuller, deeper bass response, which reinforced the track’s impact while maintaining excellent integration with the speakers.
Finally, Led Zeppelin’s “Ramble On” clearly showcased this model’s superior bass response: the bass line had greater breadth and went deeper, while the overall sound remained well-controlled. Despite this extra energy, the subwoofer remained difficult to pinpoint when carefully calibrated.
The PL2 will therefore come into its own in rooms that are 25 m² or larger, where its extension and power reserve can be fully expressed.
REL Planar PL1 compared to the REL HT/1510 Predator
At a similar price point, the REL HT/1510 Predator takes a very different approach than the Planar PL1. Its imposing sealed cabinet houses a 15″ driver powered by a 1,000-watt RMS amplifier. It extends down to 20 Hz at -6 dB, compared to 31 Hz for the PL1, and prioritizes impact, sound pressure, and extension in the sub-bass range. It is also significantly larger, measuring nearly 50 cm deep and weighing 45 kg.
The Planar PL1 takes an almost opposite approach. Its two 6.5″ active drivers, combined with a 10″ passive radiator and 300 watts RMS of power, offer less extension in the extreme bass, but its cabinet, which is only 14.4 cm deep, makes it much easier to mount flush against a wall. Its Speakon line-level connection and the included AirShip Direct wireless system further enhance its hi-fi capabilities and installation flexibility.
The choice therefore depends primarily on the intended use and the constraints of the room. The HT/1510 Predator is better suited for a home theater setup and those seeking a more intense and deeper bass response, while the Planar PL1 prioritizes discretion, integration with the speakers, and a much less intrusive installation.
Rel Planar PL2 compared to the Rel Acoustics S/550
Priced in the same range, the REL Acoustics S/550 features a significantly more conventional design than the Planar PL2. Its 445 x 372 x 500 mm cabinet houses a 10″ CarbonAlloy front-firing driver paired with a 12″ down-firing passive radiator. Like the PL2, its class D amplifier delivers 550 watts RMS. However, the S/550 goes deeper, with a claimed frequency response that reaches 19 Hz at -6 dB, compared to 24 Hz for the Planar.
This difference reflects two distinct approaches. The S/550 favors a traditional design capable of moving more air and extending the response deeper into the sub-bass range. The Planar PL2, on the other hand, features an 8″ FlatPiston driver, a 10″ rear passive radiator, and, most notably, a cabinet that is only 144 mm deep, designed to take advantage of boundary effect coupling with the wall.
The PL2 therefore has the edge when seamless integration into the room is a priority: its shallow depth and the included AirShip Direct system make it easy to install discreetly. The S/550 requires more floor space and offers the AirShip Direct connection as an option, but its deeper cabinet and larger drivers give it superior capability for reproducing the deepest bass.
Who are the Rel Acoustics Planar PL1 and PL2 subwoofers designed for?
The REL Acoustics Planar PL1 and PL2 are designed primarily for setups where seamless integration into the room is just as important as bass reinforcement. Their shallow depth and ability to be placed right up against a wall make them easy to pair with a traditional hi-fi system, architectural speakers, wireless speakers, a soundbar, or even a TV with a subwoofer. They add more depth and extension at the lower end of the frequency spectrum without taking up the space in the room that a traditional subwoofer would.
The Planar PL1 is particularly well-suited for moderately sized rooms, around 15 to 20 m². Its tight and precise reproduction complements bookshelf speakers or compact floorstanding speakers well without overemphasizing the bass.
The Planar PL2 is better suited for spaces of 25 m² or larger. Its more powerful amplification and wider frequency response deliver greater depth, breadth, and presence, while maintaining the same wall-mount design philosophy.
In both cases, the high-level connection will appeal primarily to hi-fi enthusiasts, while the LFE input allows for additional use in a home theater setting. REL actually recommends using both connections together in this context.
