Rel Acoustics T/9x: energetic and intense bass for music and home theater


Mis à jour le 10 March 2023.

Rel Acoustics T/9x review: 3/4 view
Firmly anchored on its massive feet, the Rel T/9x houses a 9.8” driver and passive radiator, as well as a 300 watt Class A/B amplifier. Will it outperform its predecessor, the Rel T-9i?

The Rel Acoustics T/9x subwoofer is equipped with a 9.8” driver and passive radiator. Its amplification reaches 300 watts RMS and offers bass as low as 27Hz. It is the successor to the Rel T-9i, from which it inherits the main characteristics in a more compact format, with some improvements. Intended for both hi-fi and home theater use, the Rel T/9x is priced at 1,590 euros. Does it do better than its predecessor, hailed by the press for its vitality and intensity?

Rel Acoustics T/9x: packaging & accessories

The Rel Acoustics T/9x subwoofer comes with a user manual, a power cable and a fabric grille. The manufacturer also includes a cable designed to connect the sub to the speaker terminals on an amplifier. This cable has a Speakon connector at one end and three stripped wires at the other.

Rel Acoustics T/9x: accessories
The Rel Acoustics T/9x subwoofer comes with a power cable and a high level Speakon cable. The manufacturer also includes a pair of fabric gloves and a user manual.

Rel Acoustics T/9x: presentation

The Rel Acoustics T/9x subwoofer is the successor to the Rel T-9i model and uses the same acoustic formula. Consequently, it features a front-firing driver and down-firing passive radiator, both equipped with new cones and surrounds. This model has the same sophisticated finish with a beautiful high gloss cabinet that, inevitably, gets covered in fingerprints and dust…

Rel Acoustics T-9i and T/9x
On the left, the Rel T-9i and on the right, the Rel T/9x. The latter has a slightly more stocky build and features rounded edges.

The T/9x’s chassis is more stocky-looking and now has rounded edges. As a result, it seems less imposing and even more appealing. The acoustic fabric cover is held in place by four tabs to be inserted into the holes intended for this purpose. We would have preferred a magnetic system that does not leave any visible fixation holes on the front panel. The T/9x still benefits from 300-watt amplification. However, the manufacturer promises greater responsiveness and intensity in the bass compared to the previous model.

9.8” driver + passive radiator

Rel Acoustics T/9x: new driver
The Rel T/9x’s new 9.8” driver features a new, more rigid cone and an optimized surround to provide a high excursion. The goal is to achieve faster and more intense lows.

The Rel T/9x has a 9.8” long-throw front-firing driver. Its passive radiator is the same size and is directed towards the floor to obtain an omnidirectional radiation of the sound waves. Their cone is made of an aluminum and paper composite and benefits from a new surround. Rigidity and lightness are combined to offer optimal responsiveness. The cone’s excursion ensures a high acoustic pressure without distortion, but with a lot of energy.

Rel Acoustics T/9x: passive radiator
The Rel T/9x’s passive radiator is down-firing. This allows the low frequencies to be distributed evenly throughout the room. On the rear of the subwoofer is a large, aluminum fin heat sink that cools the amplifier.

300 watts of power

The main advantage of Rel Acoustics subwoofers is their high current amplification. The Rel T/9x is no exception and features a 300-watt amplifier and an impressive power supply. Consequently, it is able to reproduce the attack and body of notes with energy and rapidity. It also manages to preserve the echoes during the release. Despite the passive enclosure, the bass is responsive and doesn’t lag. And although the power output hasn’t been increased, the T/9x benefits from optimized MOSFET transistors to improve transparency and reactivity.

High level, low level and LFE inputs

The Rel Acoustics T/9x subwoofer’s connectors include an RCA mono low level input, an RCA LFE input and a high level input. As is the case with all of Rel Acoustics’ subs, the latter uses the Speakon format. Combining robustness and ease of use, this connector features an anti-pullout locking system.

Rel Acoustics T/9x: high level Speakon connector
It is possible to connect the Rel Acoustics T/9x subwoofer to an amplifier via a high level connection thanks to the dedicated cable provided by the manufacturer. This connection ensures a better integration of the lows with the other frequency ranges.

The high level connection allows the same signal to be sent to both the speakers and the subwoofer. This ensures a better integration of the lows with the other frequency ranges, notably by preserving the timing and the breadth of the source signal. To this end, the manufacturer provides a dedicated cable that is 10 meters long. The user guide lists the various connections that can be used depending on the associated amplifier, with accompanying illustrations.

Rel Acoustics T/9x: Speakon cable
All Rel Acoustics subwoofers equipped with a Speakon high level input come with a cable to connect the sub to the amplifier’s speaker terminals.

A specific 9-pin connector is also present on the back of the subwoofer. It is used to connect the REL Arrow wireless transmission module.


The control interface is located on the back of the Rel Acoustics T/9x subwoofer. It allows you to set the phase (0 or 180°) and adjust the crossover frequency (30 to 120Hz). The volume can be adjusted separately for the high/low level inputs and the LFE input. This allows you to have two separate settings for hi-fi and home theater use, which is ideal if you want to connect this subwoofer to two amplifiers.

Rel Acoustics T/9x: rear
Next to the connectors are the controls for adjusting the crossover and for adjusting the volume of the high and low level inputs separately.

Key specifications

  • 9.8” front-firing driver
  • 9.8” down-firing passive radiator
  • Power output: 300 watts RMS (class AB)
  • Low frequency extension: 27Hz (-6 dB)
  • Crossover: 20 – 120Hz
  • Low level input (mono, RCA)
  • High level input (stereo, Neutrik Speakon)
  • LFE.1 port (RCA)
  • Input for REL Arrow wireless transmission module
  • Dimensions (WxHxD): 370 x 340 x 393mm
  • Weight: 20.6kg

Rel Acoustics T/9x: configuration

For stereo listening sessions, we paired the Rel Acoustics T/9x with the Sonus Faber Lumina II and Elipson Prestige Facet 8B bookshelf speakers. We used the high level connection with the included Speakon cable. The red connector and yellow cable were connected to the positive terminals of the amp’s two speaker outputs, and the black cable was connected to one of the two negative terminals. 

The volume of the subwoofer is adjusted using the High/Low Level control to match the volume of the speakers. We set the sub’s high crossover frequency slightly above the low crossover frequency of the associated speakers. We checked the overlap area by ear to make sure there were no peaks or valleys. 

For home theater sound, we connected the Rel Acoustics T/9x to the Onkyo TX-RZ840AV receiver. The latter was used to power a Focal home theater speaker pack. We simply had to connect the receiver’s LFE output to the .1/LFE level input of the subwoofer using a subwoofer cable. We then adjusted the sub’s volume (.1/LFE level potentiometer) so that it was consistent with the speakers before starting the automatic calibration process of the receiver.

Rel Acoustics T/9x: listening impressions


Listening to music with the Elipson Prestige Facet 8B and Sonus Faber Lumina II speakers took on a whole other dimension when paired with the Rel Acoustics T/9x subwoofer. 

In addition to greater extension and presence in the low frequencies, we enjoyed a more spacious and better-defined soundscape. By adding extra information to the low end of the spectrum, the Rel Acoustics T/9x improved the width and depth of the soundstage. The music unfolded more fully in the listening space. The instruments and artist seemed to be even more present in the room.

The amplification didn’t show any signs of weakness when it came to moving the driver’s cone. As for the passive radiator, it was perfectly in sync with the same tempo. This Rel subwoofer displayed unwavering responsiveness and was incisive during attacks, without any lag.

Rel Acoustics T/9x + Sonus Faber Lumina II
For hi-fi listening sessions, we paired the Rel Acoustics T/9x subwoofer with Sonus Faber Lumina II bookshelf speakers.

With Manu Katché’s album Neighbourhood (Qobuz – 24/96), the bass and tom drums had much more presence. The Rel T/9x gave them excellent impact, while at the same time delivering a plethora of details in the lowest octaves. The subtlety of this subwoofer also served the double bass, whose phrasing unfolded with more roundness and depth. 

The Rel Acoustics T/9x delivered the bass masterfully to the syncopated rhythms of Take the Power Back (Rage Against the Machine – Qobuz – 24/44). The rhythm was very well controlled and the attacks perfectly in place. The same goes for Feel Good Inc (Gorillaz – Demon Days – Qobuz 16/44). This subwoofer allowed us to enjoy the richness of these tracks by reproducing the lowest notes with both intensity and impact, but also a lot of nuance and a keen sense of rhythm.

Home theater

In a home theater installation, in both stereo and multichannel, the Rel Acoustics T/9x was a powerhouse. Its power output of 300 watts and substantial power reserve gave it the necessary control and endurance to keep up with the most demanding action scenes.

Rel Acoustics T/9x + Elipson Prestige Facet 8B
In a home theater setup with a pair of Elipson Prestige Facet 8B speakers, the Rel T/9x subwoofer provided extra presence and realism.

The Rel T/9x wasn’t reluctant when it came to reproducing the roar of the F/A-18 Super Hornet from Top Gun Maverick! The same goes for the intensity of the kung fu scenes in Everything, Everywhere, All at Once. The subwoofer was at the service of the supercharged soundtrack and provided great energy. On the eerie and often oppressive music of the series The Last of Us, this subwoofer was perfect for accentuating the intensity of the most dramatic scenes.

Rel Acoustics T/9x in a home theater installation
The flight scenes in Top Gun Maverick took on a whole new dimension with the Rel Acoustics T/9x. The LFE channel took full advantage of the subwoofer’s responsiveness and energy.

Rel Acoustics T/9x: compared to…

Rel Acoustics T-9i

The T9-1 and T/9x are relatively similar when it comes to their design. However, as with fine wine, the formula improves over time. Firstly, the Rel T/9x is more appealing with its stockier and slightly more compact silhouette. Secondly, the changes made to the amplification (new MOFSET transistors), the cone and the surround have improved the depth and impact of the lows, without any distortion. Most importantly, they have optimized the responsiveness of the sub. Lastly, the Rel T/9x provides the same musicality for hi-fi setups, with the Welsh manufacturer’s trademark characteristics: magnitude, nuance and precision.

GoldenEar SuperSub X

Available for €1,799, the GoldenEar SuperSub X is one of the most powerful models from the American manufacturer. In an ultra-compact format, it features an 1,400-watt digital amplifier to power two 7.8” drivers that are supported by two large passive radiators. The GoldenEar sub’s effectiveness with movies and video games is formidable, outperforming the Rel model. For hi-fi listening sessions, however, the T/9x takes the lead with a sense of nuance and a capacity for integration that is unequaled.

Rel Acoustics T/9x: who is it for?

The Rel Acoustics T/9x subwoofer is ideal to accompany a pair of bookshelf or floorstanding speakers in a high fidelity installation. Its stunning finish and relatively compact format will definitely appeal to those who love beautiful objects. It is also comfortable in home theater and gaming setups to add extra intensity and realism to soundtracks.

Rel Acoustics T/9x: conclusion

With the Rel Acoustics T/9x, the Welsh manufacturer succeeds in renewing one of its flagship models without losing what made the latter special. The musical qualities of its predecessor are magnified: magnitude, reactivity, timing, nuance and precision are still main characteristics that masterfully enhance the music. Associated with a pair of bookshelf speakers, or even a pair of floorstanding speakers, the Rel T/9x transforms the high fidelity experience. 

While it isn’t the most impressive home theater model in this price range, the Rel T/9x is very comfortable with movie and video game soundtracks. The sound pressure and rich, intense lows make every home theater session truly enjoyable. 

Once again, Rel Acoustics proves that sheer power is not the only way to achieve powerful and musical bass.

We liked

  • The reactive, detailed and nuanced lows
  • The perfect integration in hi-fi setups
  • The impact and intensity in home theater settings
  • The overall look

We would have liked

  • A matte finish that attracts less dust… 
  • A magnetic grille

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