Полочная акустика — Raidho Acoustics D1.1

The D1.1 is a compact two-way monitor for stand mounting, made by Raidho Acoustics of Denmark, designed by Michael Borresen. It replaced the earlier D1 and keeps only that model's main cabinet and tweeter. The baffle, back plate, crossover and rear connections were all redesigned, and the mid/bass driver received a modified motor structure and surround, which raised efficiency by 1.5 dB compared with the D1.

Key specs that matter

A 115 mm Raidho Diamond Driver handles bass and midrange and hands over to a ribbon tweeter at 3 kHz through a second-order crossover. Frequency range is 50 Hz to 50 kHz. Sensitivity is 85 dB measured at 2.83 V and 1 m, and nominal impedance is stated as above 6 ohm. Raidho asks for amplification of more than 50 W. Each cabinet is 200 mm wide, 360 mm high and 410 mm deep and weighs 13 kg. Finishes are black piano, walnut burl veneer or any paint colour the buyer specifies.

Engineering and use context

Raidho builds the mid/bass unit in-house, with a diamond-coated ceramic cone, an N52 neodymium magnet and an underhung titanium voice coil. The diamond layer on the ceramic is applied to reduce distortion, and Raidho states that the driver shows no measurable distortion in its transient response. The tweeter is a planar magnetic design handmade in Denmark, working in a sealed chamber and driven by an array of neodymium magnets. Its aluminium foil is 11 microns thick and weighs 20 milligrams, giving roughly one fiftieth of the mass of an ordinary dome tweeter, and there is no voice coil. Raidho puts the first breakup of this diaphragm at 82 kHz, far above the audible band. The cabinet tapers towards the rear in a boat-back shape, and the two-piece aluminium front baffle is shaped to time-align the two drivers, which are fixed to it without visible fasteners. Bass loading is by a port in the rear panel, fitted with an aluminium flare that calms the air as it leaves the enclosure. Connection is through 4 mm gold-plated sockets instead of conventional binding posts.

Pairing

The low sensitivity and the high power requirement point to solid-state amplifiers with good reserves rather than low-output valve designs. The dedicated stands use a loose ball-and-cup arrangement in their four feet and a ball-bearing interface between the speaker and the top plate to control resonance, and each stand is rated for a load of 90 kg.

Alternatives

The Raidho TD1.2 is a larger-driver stand-mount with a 6.5 inch Tantalum Diamond mid/bass unit.