Полочная акустика — GoldenEar BRX

The BRX, short for Bookshelf Reference X, is a two-way bookshelf speaker designed by GoldenEar Technology of Stevenson, Maryland. Its drivers are taken from the company's floorstanding Triton towers, and its ribbon tweeter is the one fitted to the Triton Reference. Its UK price was GBP 1,499 per pair, and it is offered only in hand-rubbed piano black lacquer.

Key specs that matter

GoldenEar pairs a Reference High-Velocity Folded Ribbon AMT tweeter, one 6 inch high-definition cast-basket mid/bass unit with a polypropylene cone and two 6.5 inch planar low-frequency radiators on the side walls. The radiators add up to 155.48 cm2. Rated sensitivity is 88 dB for 1 W at 1 m into 4 ohm, which equals 2.83 V at 1 m, and the nominal impedance is 4 ohm. GoldenEar quotes 42 Hz to 25 kHz as typical response, with the anechoic bass falling to -6 dB on axis at 65 Hz. The recommended amplifier power is 20 to 250 W per channel. The cabinet is 20.5 cm wide, 31.1 cm deep and 30.8 cm high, and one speaker weighs 5.44 kg.

Engineering and use context

This high-frequency unit descends from the Air Motion Transformer that Oskar Heil invented in the 1970s. A thin conductive membrane is pleated like an accordion and set in front of a neodymium magnet, so the folds push air out faster than a conventional ribbon of the same size. Bass loading comes from the two flat radiators, one on each side of the enclosure, placed so that their reactive forces cancel and the cabinet is not rocked. GoldenEar calls them inertially balanced infrasonic radiators. They take the job of a reflex port without an opening in the cabinet, which avoids port turbulence and pipe resonances. A balanced crossover joins the tweeter and the mid/bass unit. The cabinet has curved walls and a curved front grille in fabric that rests on a lip at the base, while the radiators sit behind metal grilles glued in place. A single pair of binding posts on the back takes the speaker cable.

Pairing

The low nominal load makes the BRX a match for transistor amplifiers happy with a demanding impedance, and the wide recommended power range leaves room for large power amplifiers. To extend output under the rated range, a powered GoldenEar subwoofer like the SuperSub X can be added to form a 2.1 system.

Alternatives

The GoldenEar Aon 3 is a larger bookshelf design with a 7 inch mid/bass driver and two 8 inch side radiators.