Audio T Verdict
The REL HT/1205 MKII delivers the extra scale and dynamic headroom needed for more ambitious home cinema systems without requiring the much larger cabinet of the HT/1510 Predator II.
Its front-firing 300mm CarbonGlas driver and 500W Class D amplifier provide powerful, tightly controlled effects, while the sealed enclosure and fast analogue filters help retain definition during rapid changes in level.
It is primarily designed for RCA LFE connection from an AV receiver or processor, although its stereo low-level inputs also make it suitable for compatible active speakers and mixed-use systems.
The HT/1205 MKII does not include REL’s High Level Speakon input. It should therefore be chosen for systems that provide a suitable line-level or dedicated subwoofer output.
REL HT/1205 MKII Home Cinema Subwoofer
The REL HT/1205 MKII is a high-output active subwoofer developed for home cinema, gaming, television and music systems requiring fast, powerful low-frequency reproduction.
A front-firing 300mm CarbonGlas driver is powered by a 500W RMS Class D amplifier, producing extension to 22Hz at the stated minus 6dB point.
It can operate as the principal subwoofer in a medium-sized or larger cinema room, form part of a multiple-subwoofer installation or provide dedicated LFE support alongside REL models connected to the main loudspeaker channels.
300mm CarbonGlas Driver
The long-throw active driver combines a lightweight glass-fibre primary cone with an inverted carbon-fibre centre cap.
This CarbonGlas construction provides the stiffness required for powerful cinematic effects while keeping moving mass low enough to preserve speed and definition.
A substantial motor system and revised suspension control the driver throughout its available movement, allowing large effects to retain their impact without becoming loose or indistinct.
Closed-Box, Front-Firing Design
The HT/1205 MKII uses a sealed cabinet without a reflex port or passive radiator.
Air trapped within the enclosure helps control the driver’s movement and supports a gradual low-frequency roll-off, while avoiding the airflow noise associated with an open port.
The front-firing arrangement also makes positioning straightforward across a wide range of firm floor surfaces.
22Hz Low-Frequency Extension
REL specifies low-frequency extension to 22Hz at minus 6dB.
This allows the HT/1205 MKII to reproduce the deep effects contained within film, television and game soundtracks, as well as the lowest fundamentals found in electronic, orchestral and live music.
The extension and output achieved at the listening position will depend on room dimensions, placement, crossover settings and the behaviour of the surrounding boundaries.
500W Class D Amplifier
A 500W RMS Class D amplifier provides the current delivery and headroom required for sudden low-frequency peaks.
The amplifier uses uprated power supplies and output components to maintain control during demanding sequences while operating efficiently within the sealed cabinet.
Electronic Set-Safe, DC fault and output-short protection help safeguard the amplifier and driver under abnormal operating conditions.
Fast Analogue PerfectFilter Circuitry
REL’s analogue PerfectFilter circuitry combines fast crossover filters, low-frequency extension control and integrated protection.
The secondary filters are designed to preserve the pressure and upper-bass energy that give explosions, impacts and large-scale effects their convincing sense of force.
An analogue subsonic filter begins below the subwoofer’s normal operating range, reducing unnecessary driver movement caused by extreme infrasonic soundtrack information.
RCA LFE Connection
For home cinema use, connect the subwoofer output of a compatible AV receiver or surround processor to the HT/1205 MKII’s designated RCA LFE input.
This carries the dedicated low-frequency effects channel contained within film and multichannel soundtracks.
The connected processor normally controls bass management, loudspeaker crossover frequencies, delay and overall subwoofer level.
Stereo Low-Level RCA Inputs
The two RCA sockets can also accept left and right low-level signals from a compatible pre-amplifier, integrated amplifier, processor or active loudspeaker system.
In this arrangement, the REL’s variable crossover control determines the upper frequencies reproduced by the subwoofer.
This gives the HT/1205 MKII useful flexibility in mixed-use rooms, provided the system has a suitable variable line-level output.
No REL High Level Speakon Input
The HT/1205 MKII does not include the amplifier-level Speakon connection found on REL’s Serie T/x, Classic, Serie S and Reference models.
It must be connected using its RCA low-level or LFE inputs. REL Bassline Blue, Arrow and Airship II are therefore not the correct accessories for this subwoofer.
RCA Daisy-Chain Outputs
Matching RCA outputs allow the low-level or LFE signal to be passed to another compatible subwoofer.
This can simplify a multiple-subwoofer installation by avoiding the need to run an individual cable from the processor to every cabinet.
Each connected subwoofer retains independent level, crossover and phase controls and should be adjusted for its position within the room.
HT-Air MKII Wireless Compatibility
The HT/1205 MKII is compatible with the optional
REL HT-Air MKII wireless system
.
HT-Air MKII carries a low-level or LFE signal over an uncompressed 5.8GHz wireless connection, avoiding the need for a long RCA cable across the room.
The transmitter connects to the AV receiver, processor or suitable line-level output, while the receiver connects to the REL.
Wireless transmission carries the audio signal only. The subwoofer and wireless components retain their normal power connections.
Positioning and Calibration
Begin with the HT/1205 MKII along the same wall as the screen and front loudspeakers.
A corner position can increase output and extension, while moving the cabinet away from the corner may provide smoother bass across the listening area.
Set the REL’s level conservatively before running the AV receiver’s room-correction system, then review the resulting crossover, distance and level settings.
Automated calibration provides a useful starting point, but final checks with familiar films and music remain important.
Single or Multiple Subwoofers?
Single HT/1205 MKII
- Strong choice for medium-sized and larger rooms
- Requires one signal and mains connection
- Simplest placement and calibration arrangement
- Provides substantial output from one position
- Suitable for dedicated and mixed-use systems
Multiple Subwoofers
- Can improve consistency across several seats
- Provides additional combined headroom
- May reduce the effect of individual room resonances
- RCA outputs support compatible daisy chaining
- Each cabinet requires independent setup
The HT/1205 MKII is intended for conventional floor placement rather than vertical REL line-array stacking.
REL HT/3D System Planning
REL’s HT/3D approach uses multiple subwoofers to support different groups of loudspeakers within a surround system.
The HT/1205 MKII can provide the principal LFE impact while compatible music-led REL models underpin the main, centre or surround channels.
The correct number and position of subwoofers should be planned around the room, speaker layout, seating arrangement and intended playback levels.
HT/1003 MKII, HT/1205 MKII or HT/1510 Predator II?
REL HT/1003 MKII
- 250mm CarbonGlas active driver
- 300W RMS Class D amplifier
- 24Hz low-frequency extension
- More compact cabinet
- Suited to small and medium-sized rooms
View the REL HT/1003 MKII
REL HT/1205 MKII
- 300mm CarbonGlas active driver
- 500W RMS Class D amplifier
- 22Hz low-frequency extension
- Greater scale and dynamic headroom
- Suited to medium-sized and larger rooms
REL HT/1510 Predator II
- 380mm CarbonGlas active driver
- 1,000W RMS amplification
- 20Hz low-frequency extension
- Substantially greater output and cabinet volume
- Designed for demanding cinema installations
View the REL HT/1510 Predator II
Cabinet and Finish
The sealed cabinet uses a horizontally oriented line-grained composite finish with a substantial 15mm top panel.
Five coats of hand-polished high-gloss lacquer protect the top surface, with a discreet REL logo beneath the finish.
The cabinet design is intended to sit naturally alongside contemporary televisions, home cinema speakers and other REL models.
System Matching
Well Suited To
- Medium-sized and larger home cinema rooms
- AV receivers with an RCA subwoofer output
- Compact and floorstanding cinema speakers
- Gaming and television systems
- Active systems with variable line-level outputs
- Single and multiple-subwoofer installations
- Wireless LFE systems using HT-Air MKII
Check Before Installation
- No High Level Speakon input is provided
- A suitable RCA interconnect is required
- HT-Air MKII is the compatible wireless system
- Allow ventilation around the amplifier panel
- Do not obstruct the front-firing driver
- Retain access to the controls and mains switch
- Every additional subwoofer requires calibration
Setup Guidance
- Begin along the same wall as the screen
- Use the LFE input with an AV receiver
- Start with a conservative level setting
- Check phase before final adjustment
- Review automatic room-correction results
- Test several seating positions
- Complete final tuning with familiar material
Browse our
home cinema subwoofers
,
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,
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,
wireless accessories
and
subwoofer and system cables
, or explore the
REL range at Audio T
.
Key Features
- High-output active home cinema subwoofer
- Closed-box cabinet with front-firing driver
- 300mm long-throw CarbonGlas cone
- Glass-fibre main cone with carbon-fibre centre cap
- Steel driver chassis
- 22Hz low-frequency extension at minus 6dB
- 500W RMS Class D amplifier
- Fast analogue REL PerfectFilter circuitry
- Protective analogue subsonic filtering
- Electronic Set-Safe protection
- Stereo low-level RCA inputs
- Dedicated RCA LFE connection
- RCA outputs for compatible daisy-chain systems
- Variable crossover adjustment
- 0 or 180-degree phase selection
- Standby and always-on operating modes
- Compatible with REL HT-Air MKII
- Suitable for single and multiple-subwoofer systems
- Line-grained composite cabinet
- Hand-polished high-gloss top panel
- Three-year REL warranty, subject to current terms
Frequently Asked Questions
Is the HT/1205 MKII designed mainly for home cinema?
Yes. It is developed primarily for powerful LFE reproduction, although its stereo low-level inputs also support compatible music and active-speaker systems.
Does it have REL’s High Level Speakon input?
No. The HT/1205 MKII uses RCA low-level or LFE connections and is not designed for REL High Level cables.
Can it connect directly to an AV receiver?
Yes. Connect the receiver’s subwoofer output to the designated RCA LFE input using a suitable subwoofer interconnect.
Is an RCA signal cable included?
No. Select a suitable low-level or LFE interconnect for the required cable route.
Can the HT/1205 MKII connect wirelessly?
Yes. It is compatible with the optional REL HT-Air MKII transmitter and receiver system.
Can two HT/1205 MKII subwoofers be used together?
Yes. Multiple units can increase headroom and improve bass consistency across several listening positions.
How does it differ from the HT/1003 MKII?
The HT/1205 MKII has a larger 300mm driver, 500W amplification, deeper 22Hz extension and greater output for larger rooms.
How large and heavy is it?
It measures approximately 413 x 387 x 438mm and weighs 19.6kg.
Why Buy From Audio T?
- Home cinema subwoofer and speaker-matching advice
- Comparison with other REL Serie HT models
- AV receiver crossover and bass-management guidance
- Single and multiple-subwoofer system planning
- Room-positioning and phase-setting assistance
- Level, crossover and delay setup support
- HT-Air MKII wireless compatibility advice
- RCA and LFE cable recommendations
- REL HT/3D home cinema planning
- Ongoing home cinema system support
Contact your local Audio T store
to discuss positioning, connecting and calibrating the REL HT/1205 MKII within your home cinema system.