Напольная акустика — Raidho Acoustics TD4.2

Raidho Acoustics, a Danish manufacturer with its own driver production, offers the TD4.2 as a three-way tower in its TD Series. Raidho names it the first model in the TD line with a true MTM configuration, where two midrange drivers frame the tweeter, and the symmetrical arrangement continues down through the bass section. The letters TD refer to the Tantalum Diamond coating on the cones.

Key specs that matter

The complement is one TD ribbon tweeter, two 5 inch Tantalum Diamond midranges and two 6.5 inch Tantalum Diamond bass drivers. Crossover points sit at 400 Hz and 2.4 kHz with stepped slopes. The rated range is 25 Hz to 50 kHz within 3 dB, sensitivity is 88 dB at 2.83 V and 1 m, and nominal impedance is 6 ohm. Raidho gives a power requirement of 50 to 300 W. Overall dimensions including feet are 440 mm wide, 1,585 mm high and 600 mm deep, the enclosure footprint is 200 x 600 mm, and each speaker weighs 64 kg. Piano black and walnut burl are standard, and other colours can be ordered.

Engineering and use context

Raidho uses several bass drivers instead of one large woofer, stating that multiple units can move the same volume and reach as deep as much bigger cones while giving a better impulse response. The smaller drivers also allow a slim front plate, which reduces diffraction. The reflex port is at the rear and is described by the maker as impulse optimized. Raidho worked with the Danish Technical Institute on the five-layer cone, which stacks aluminium and ceramic, then a tantalum layer and finally artificial diamond, about 1.5 carat applied to each membrane in a layer 10 microns thick. According to Raidho the TD layers are 50 times stiffer than ceramic-only membranes and raise the breakup mode to 20 kHz. The motor combines an N52 neodymium magnet with an underhung titanium voice coil of square wire, and the magnet system and basket are shaped like a turbine to avoid reflections. A planar magnetic foil forms the ribbon tweeter, only 11 microns thick, and the TD version gained 3 dB of sensitivity through a new magnet, waveguide and rear panel design. Mundorf parts fill the crossovers, whose point-to-point connections are made by hand, and internal wiring is Nordost cable throughout.

Pairing

Its impedance and sensitivity figures place only moderate demands on amplification within the stated power range.

Alternatives

The Raidho TD3.2 is a smaller three-way floorstander of the TD Series with one midrange in its own enclosure and three bass drivers.