Subwoofers — MAGNAT Cinema Ultra SUB 300-THX

The Cinema Ultra SUB 300-THX is the powered subwoofer of the Cinema Ultra home theatre range from the German brand Magnat, and it carries THX Ultra2 certification. In the same family Magnat lists the Cinema Ultra LCR 100-THX for the front left, centre and right positions, the Cinema Ultra RD 200-THX surround model and the Cinema Ultra AEH 400-ATM, so the subwoofer is designed as the low-frequency base of a complete certified cinema set rather than as a standalone add-on.

Key specs that matter

A single 32 cm (12.6 inch) long-throw woofer is the only driven unit. Two passive radiators, each also 32 cm in diameter, support it, and Magnat quotes a frequency response of 18 to 200 Hz. Its internal Class D power stage delivers 550 W RMS, with 1,100 W given as the peak figure, and peak output is specified at more than 115 dB SPL. The cabinet measures 46.5 x 46.5 x 50 cm and the unit weighs 32.5 kg. The front baffle is finished in black silk matte lacquer while the rest of the body is covered in an anthracite textured film.

Engineering and use context

Instead of a bass reflex tunnel the enclosure relies on the pair of passive cones, which avoids port noise at high output and lets the long-throw driver load a closed MDF box. The baffle is 45 mm thick and internal bracing is used against panel resonance. The amplifier is a custom Magnat design fed by a switch-mode power supply. Two input paths are provided - a THX input and a stereo input. In THX mode the subwoofer runs without its own low-pass filter, because the bass management of a THX processor or AV receiver already defines the crossover. In the stereo or line mode the crossover can be set between 40 and 180 Hz, and volume and phase (0 or 180 degrees) are adjustable as well. Signal sensing switches the subwoofer on automatically once audio arrives, and the auto standby function draws less than 0.5 W. Detachable fabric covers hide the drivers, and large resonance-absorbing feet can be swapped for spikes.

Pairing

Obvious companions are the remaining Cinema Ultra speakers plus a THX-certified AV receiver or processor, connected through the THX input so that the controller handles bass management. Used with a stereo amplifier or a preamplifier that lacks its own crossover, the line input and adjustable low-pass filter allow the SUB 300-THX to be blended with main speakers of various sizes.

Alternatives

The Magnat Alpha RS 12 is a smaller subwoofer from the Alpha line for systems that do not need THX Ultra2 certification.