The HT/1205 MKII is the larger of two subwoofers in REL’s Serie HT range, sitting above the HT/1003 MKII. Designed primarily for home cinema, it pairs a 300 mm (12″) CarbonGlas™ driver with a 500 W RMS NextGen5 Class D amplifier inside a sealed cabinet, delivering controlled, high-output bass tuned for film and gaming applications.
Driver & Cabinet
The CarbonGlas™ cone combines a glass-fibre primary structure with a true carbon-fibre inverted dust cap, mounted in a steel chassis. This composite construction keeps moving mass low while maintaining the rigidity needed to track fast transients at high excursion. The sealed enclosure provides a controlled, predictable roll-off that suits the tight, punchy bass demanded by film soundtracks.
Amplification
The NextGen5 Class D amplifier module uses MOSFET power devices rated at 800 W, operating well within their limits at the 500 W RMS output. REL states the MKII revision delivers 50% more output than the original HT/1205, alongside improved transient response and tighter control at high listening levels. Thicker circuit boards and upgraded power supplies contribute to long-term reliability.
Signal Processing
REL’s PerfectFilters™ processing incorporates ultra-fast crossover slopes, an elevation filter designed to extend flat bass response into the low 20 Hz region, and an integrated limiter. An all-analogue subsonic filter engages from 8 Hz to attenuate infrasonic content that would otherwise waste amplifier headroom.
Connectivity
Rear-panel connections include dual-purpose low-level stereo RCA inputs that double as an LFE input, plus daisy-chain RCA outputs for running a second subwoofer. The HT/1205 MKII is compatible with the optional HT-Air wireless module, which transmits a 5.8 GHz uncompressed signal over distances up to 18 m (60 ft) using the same LSIC chip found in REL’s AirShip II.
Build & Finish
The cabinet is finished in a horizontally grained white composite, topped with a 15 mm lacquered top plate that receives five coats of hand-rubbed high-gloss white lacquer. A discreet REL logo is set within the top layer. Aluminium feet provide stable, vibration-resistant support.
| Active Driver | 300 mm (12″) CarbonGlas™ long-throw, inverted carbon-fibre dust cap, steel chassis |
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| Amplifier | NextGen5 Class D, 500 W RMS (MOSFET devices rated 800 W) |
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| Frequency Response | −22 Hz (−6 dB) |
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| Cabinet Type | Sealed (front-firing driver) |
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| Inputs | Dual-purpose low-level stereo RCA / LFE RCA |
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| Outputs | Daisy-chain low-level RCA |
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| Wireless | Optional HT-Air module (5.8 GHz, up to 18 m / 60 ft) |
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| Dimensions (W × H × D) | 413 × 387 × 438 mm |
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| Weight | 19.6 kg |
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| Finish | White textured cabinet with high-gloss lacquer top plate |
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| Also Available As | Black |
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