REL T/5x Compact Subwoofer

The REL T/5x is a compact active subwoofer developed for music systems, television, gaming and home cinema.

It combines a down-firing 200mm FibreAlloy driver with a 125W RMS Class A/B amplifier, sealed cabinet and low-frequency extension reaching 32Hz at the stated minus 6dB point.

The T/5x can operate as a single subwoofer, as part of a stereo pair or within a multi-subwoofer REL 3D home cinema system.

Compact Design for Real Living Rooms

The T/5x is designed for customers who want genuine REL performance without allowing the subwoofer to dominate the room.

Its softly rounded cabinet measures approximately 300mm wide, 307mm high and 313mm deep, making it easier to position beside furniture or near the main loudspeakers than a larger subwoofer.

Although the cabinet volume is greater than that of the previous T/5i, the revised proportions and rounded corners help reduce its visual presence.

The compact dimensions make the T/5x particularly suitable for small and medium-sized listening spaces, although room layout, loudspeaker choice and required playback level should still be considered.

200mm FibreAlloy Driver

The T/5x uses a single 200mm long-throw FibreAlloy active driver.

Its composite cone combines lightweight fibre material with an inverted alloy centre cap, providing the stiffness required for controlled bass without adding unnecessary moving mass.

The revised suspension allows greater controlled movement than the previous generation, helping the driver reproduce demanding musical and cinematic information while retaining speed and definition.

A rigid steel chassis provides a stable mechanical foundation for the driver, voice coil and suspension.

Down-Firing Driver Arrangement

The T/5x positions its active driver beneath the cabinet, directing low-frequency energy towards the floor.

This helps distribute bass throughout the room while allowing REL to maintain a clean and discreet cabinet design without a visible front driver.

The down-firing arrangement also means the T/5x can operate effectively when positioned at different angles to the listening position, provided the cabinet remains upright and stable.

Closed-Box Cabinet

The T/5x uses a sealed cabinet with no reflex port or passive radiator.

Air trapped within the enclosure helps control the movement of the driver, supporting a fast response and gradual low-frequency roll-off.

The absence of a reflex port also removes the possibility of port airflow noise during demanding bass passages.

Internal bracing and laminated cabinet construction help reduce unwanted resonance so that the energy produced by the amplifier is used to drive the cone rather than excite the enclosure.

32Hz Low-Frequency Extension

REL specifies low-frequency extension to 32Hz at minus 6dB.

This gives the T/5x access to frequencies that many compact and medium-sized loudspeakers cannot reproduce with useful output.

The result can be greater weight and scale with bass instruments, orchestral music, electronic recordings, television, films and games.

Room dimensions, placement, floor construction and the listening position will all influence the extension and output achieved in practice.

125W Class A/B Amplifier

A 125W RMS Class A/B amplifier powers the FibreAlloy driver.

REL uses a high-current traditional amplifier design intended to provide strong control, tonal richness and the dynamic response required for music.

The amplifier has been refined with updated driver components and revised transformer mounting to improve transparency, speed and long-term reliability.

The output is rated as continuous RMS power rather than a short-duration peak figure.

Fully Analogue Input Filtering

The T/5x uses REL’s analogue filtering to blend its output with the main loudspeakers.

The High Level and low-level signal paths pass through an adjustable low-pass crossover, allowing the upper limit of the subwoofer’s output to be matched to the natural roll-off of the speakers.

Keeping the filtering within the analogue domain avoids unnecessary digital conversion within the normal signal path.

The T/5x does not include digital room correction or the dual parametric filters found on REL’s Reference models.

Fully Electronic Protection

REL’s electronic Set-Safe system monitors the amplifier during operation.

Additional protection is provided against DC faults and output short circuits.

These systems operate automatically but do not replace correct installation, ventilation and connection practices.

REL High Level Connection

REL’s preferred connection for many conventional stereo systems is the supplied High Level Neutrik Speakon cable.

This receives the same signal and sonic character being delivered by the main amplifier to the loudspeakers.

The main speakers remain connected directly to the amplifier and continue to receive their normal full-range signal. The T/5x is added alongside them and adjusted to support their natural low-frequency roll-off.

A nominal 10-metre Neutrik Speakon High Level cable is supplied with the T/5x.

Low-Level RCA Input

A single RCA low-level input allows the T/5x to receive a mono signal from a suitable pre-amplifier, integrated amplifier, processor or active loudspeaker system.

The source must provide a suitable variable output that follows the main system volume.

Low-level connection can be useful with active loudspeakers and equipment that does not permit a suitable High Level connection.

The low-level input shares the T/5x’s Hi/Low Level gain and crossover controls with the High Level input.

Dedicated RCA LFE Input

A separate RCA LFE input connects to the subwoofer output of a compatible AV receiver or surround processor.

This carries the dedicated low-frequency effects channel used by film, television, concert and multichannel game soundtracks.

The LFE input has its own level control and operates independently from the High Level or low-level music connection.

Bass management, loudspeaker crossover points, delay and channel level can normally be configured from the connected home cinema processor.

Simultaneous Music and Cinema Connection

The T/5x can use its High Level or low-level input for music while also remaining connected to the dedicated LFE output of a home cinema processor.

The two signal paths provide separate gain adjustment, allowing the subwoofer to integrate naturally with the main loudspeakers during stereo listening while reproducing the dedicated .1 channel during films.

This arrangement is particularly useful where the same main loudspeakers and amplifier are shared between a stereo system and home cinema processor.

Separate Hi/Low and LFE Level Controls

The Hi/Low Level control adjusts the output produced from the High Level Speakon or low-level RCA input.

The separate .1/LFE Level control adjusts the output produced from the dedicated LFE input.

These separate controls allow the T/5x to maintain one setting for music and another for home cinema without requiring repeated adjustment when changing source.

Variable Crossover Adjustment

The rear crossover control adjusts the upper frequency reproduced through the High Level and low-level signal paths.

It should be set so that the T/5x supports the natural low-frequency roll-off of the main loudspeakers without producing an obvious overlap in the upper bass.

The crossover does not control the dedicated LFE input, as the home cinema processor normally handles the relevant filtering and bass management.

An excessively high setting can make the system sound thick or reveal the location of the subwoofer, while an excessively low setting may leave a gap between the main speakers and the T/5x.

0 or 180-Degree Phase Adjustment

A two-position phase switch helps align the movement of the T/5x driver with the main loudspeakers at the listening position.

The correct setting is normally the one that produces the strongest, fullest and most coherent bass.

Phase should be established before completing the final crossover and gain adjustment.

The best setting depends on the room, speaker position, subwoofer position and listening seat rather than the brand or size of the loudspeakers alone.

Standby and Always-On Operation

UK 220V to 240V versions of the T/5x include a standby-mode switch.

Standby mode allows the amplifier to enter a low-power state when no signal is detected, while always-on operation keeps the subwoofer ready for immediate use.

The preferred setting may depend on the system, listening habits and the level of signal reaching the input.

REL Arrow Wireless Compatibility

The T/5x is compatible with the optional REL Arrow Wireless Transmitter .

Arrow can transmit a REL High Level or home cinema LFE signal without using conventional Bluetooth or household Wi-Fi.

Its receiver docks directly into the wireless interface on the rear of the T/5x, avoiding the need for a separate audio lead between the receiver and subwoofer.

REL uses uncompressed wireless transmission to preserve timing, dynamics and the character of the incoming signal.

The stated wireless range is up to approximately 15.2 metres with a clear line of sight, although walls, furniture and wireless interference may reduce the practical distance.

Bassline Blue High Level Cable

A standard 10-metre High Level cable is supplied with the T/5x.

The optional REL Bassline Blue High Level cable provides an upgraded connection for compatible amplifiers and REL subwoofers.

Bassline Blue is available in different lengths and connection versions, including configurations developed for compatible Naim amplifiers.

Confirm the correct cable version and amplifier wiring arrangement before ordering.

Positioning the REL T/5x

Begin with the T/5x positioned along the same wall as the main loudspeakers.

A corner position can increase output and low-frequency extension, while moving the cabinet away from the corner may reduce excessive room-related bass.

Small changes in position can make a significant difference, so the final location should be established by listening rather than appearance alone.

Avoid enclosing the subwoofer tightly within furniture or positioning it where the driver, controls, wireless receiver or amplifier ventilation can be obstructed.

Initial Stereo Setup

1. Place the T/5x along the same wall as the main loudspeakers.
2. Switch off the complete system before making any connections.
3. Connect the supplied High Level cable or a suitable low-level RCA interconnect.
4. Begin with conservative crossover and Hi/Low Level settings.
5. Select the phase setting that produces the strongest and most coherent bass at the listening position.
6. Adjust the crossover so the T/5x supports the natural roll-off of the main loudspeakers.
7. Increase the Hi/Low Level control until the additional bass is clearly audible.
8. Reduce the level slightly until the subwoofer no longer draws attention to itself.
9. Complete the setup using familiar music from the normal listening position.

Initial Home Cinema Setup

1. Connect the AV receiver or processor’s subwoofer output to the dedicated RCA LFE input.
2. Set the T/5x .1/LFE Level control conservatively.
3. Configure suitable loudspeaker crossover points within the processor.
4. Run the processor’s measurement and room-correction procedure where provided.
5. Review the measured subwoofer level, distance and crossover settings.
6. Check that bass effects do not overpower dialogue or the main loudspeakers.
7. Complete the setup using familiar film, television and music material.

Single T/5x or Stereo Pair?

Two subwoofers are not used purely to make the system louder. Correctly positioned and adjusted, a stereo pair can improve low-frequency balance, soundstage scale and integration with the main loudspeakers.

Can the T/5x Be Vertically Stacked?

The T/5x is not designed for vertical REL line-array stacking.

Its cabinet, feet and down-firing driver require conventional upright floor placement with clear operating space beneath the enclosure.

Customers interested in an approved vertically stacked REL system should consider compatible Serie S or Reference models instead.

REL 3D Home Cinema Systems

REL’s 3D approach uses several subwoofers to support different areas of a surround system rather than relying entirely on one cabinet.

A dedicated Serie HT model may handle the main LFE channel, while T/x subwoofers support the front loudspeakers, centre speaker or rear region.

The compact size of the T/5x can make it particularly useful where an additional subwoofer is required without introducing a large cabinet.

The number and position of subwoofers should be planned around the room, speaker layout, processor and intended listening levels.

REL T/5x, T/7x or T/9x?

All three models provide REL High Level, low-level and dedicated LFE inputs and are compatible with the optional Arrow wireless system.

The most appropriate model should be selected according to room size, loudspeaker capability, required playback level and available floor space rather than amplifier power alone.

Softly Rounded Cabinet

The T/5x cabinet uses softly rounded corners and clean surfaces to reduce its visual impact within a living room.

The curved edges also contribute to a more rigid enclosure than a simple lightweight cube, helping control unwanted panel vibration.

The down-firing driver allows the front and side panels to remain free from a visible cone or conventional speaker grille.

Piano Black and Gloss White Finishes

The T/5x is available in Piano Black Lacquer or Gloss White Lacquer.

Five coats of hand-polished lacquer create a deep gloss surface intended to complement contemporary loudspeakers, furniture and system components.

Use a clean, soft microfibre cloth for routine care and avoid abrasive cleaners that could mark the lacquer.

System Matching

Browse our home cinema subwoofers , home cinema amplifiers , home cinema speakers , wireless accessories and subwoofer and system cables , or explore the REL range at Audio T .

Key Features

• Compact REL Serie T/x active subwoofer
• Closed-box cabinet with down-firing active driver
• 200mm long-throw FibreAlloy cone
• Inverted alloy centre cap
• Steel driver chassis
• No passive radiator or reflex port
• 32Hz low-frequency extension at minus 6dB
• 125W RMS Class A/B amplifier
• Fully analogue input filtering
• High Level Neutrik Speakon input
• Single low-level RCA input
• Dedicated RCA LFE input
• Separate Hi/Low Level and .1/LFE gain controls
• Variable low-pass crossover for High Level and low-level inputs
• 0 or 180-degree phase adjustment
• Standby-mode switch on UK 220V to 240V models
• Compatible with optional REL Arrow wireless system
• Supports simultaneous music and home cinema connection
• Suitable for single and stereo-pair installations
• Suitable for REL 3D home cinema systems
• Softly rounded compact cabinet
• Piano Black or Gloss White finish
• Five coats of hand-polished lacquer
• Fully electronic Set-Safe protection
• DC fault and output-short protection
• Three-year REL warranty, subject to current terms

Frequently Asked Questions