Subwoofers — Raidho Acoustics TD8 SUB

The TD8 SUB is the smaller of the two active subwoofers that Raidho Acoustics presented at High End Munich 2025, available since September 2025. The Danish company builds it with two driven woofers and two passive radiators in a stackable cabinet, and prices are EUR 17,000 in black and EUR 19,000 in walnut. It shares its amplifier, control system and construction principles with the larger TD10 SUB but has smaller drivers and a narrower enclosure.

Key specs that matter

The active drivers are two 8 inch Ceramix units with diamond-like carbon coated cones and underhung motors, working with two 10 inch passive radiators. Power comes from a 500 W Hypex Ncore Class D amplifier, and a DSP set up from a PC handles crossover, equalisation and phase with a latency of 3 to 4 ms. Low-frequency extension is 25 Hz at ±3 dB, and the maximum sound pressure level is 118 dB. The TD8 SUB accepts high-level, RCA and XLR inputs. With its feet it measures 430 x 705 x 700 mm, the cabinet footprint is 253 x 700 mm, and the weight is 52 kg. Each unit can carry up to 90 kg when stacked.

Engineering and use context

Raidho's Ceramix cones combine a ceramic structure with a diamond-like carbon surface, which the maker uses to raise stiffness and damp resonances. Because the motor is underhung, the voice coil moves within a gap longer than itself and stays in a constant magnetic field across its stroke. Each passive radiator is larger than the active driver behind it, and the pair supplies the extra low-frequency output a port would otherwise provide, without port noise. The Class D Ncore amplifier runs with little heat, which allows the electronics to live inside a sealed wooden cabinet. With PC-based DSP, the crossover, equalisation and phase are adjusted in software rather than with knobs on the rear panel. The narrow enclosure is slim enough to stand beside a floorstander, and the stacking load rating means two or more subwoofers can be stacked. Both the Black Piano and the Walnut Burl Piano finish receive 16 coats of lacquer.

Pairing

The TD8 SUB can join Raidho's TD series floorstanders or speakers from other brands. A high-level connection takes the signal from an amplifier's speaker outputs, and the RCA and XLR inputs connect to a preamplifier, processor or dedicated subwoofer output. Two units, one per channel, give a stereo bass setup.

Alternatives

The Raidho TD10 SUB moves up to two 10 inch active drivers and four passive radiators with extension to 20 Hz.