Полочная акустика — Acora Acoustics SRB-Gem

The SRB-Gem is a two-way bass reflex bookshelf loudspeaker from Acora Acoustics, part of the company's Gemstone Series. Acora's standmount catalogue also spans the SRB, QRB, SRC-1, SRC-2, QRC-1, QRC-2 and the MRB.2 and MRC.2 families, with the Gemstone Series offered as a separate group. Like other Acora models, it uses a stone enclosure instead of wood or MDF, here built from 2 cm high-polish black granite. The standard stone is Nero Assoluto from Zimbabwe, which Acora describes as the strongest of the granites it works with, having the smallest and most homogeneous crystals and being the least likely to warp.

Key specs that matter

Acora combines a 1 inch beryllium dome tweeter and a 5.5 inch mid-woofer with a sandwich paper cone. Published data give a frequency range of 43 Hz to 35 kHz and a sensitivity of 86.5 dB at 1 W and 1 m. Nominal impedance is 8 ohm, and the recommended amplifier power spans 10 W to 150 W. Each cabinet measures about 229 mm wide, 330 mm tall and 279 mm deep, and weighs about 17.7 kg without a stand, with the exact figure varying according to the stone chosen.

Engineering and use context

The crossover is Acora's own SRC network, which the company says is laid out for phase alignment and driver integration, with an internal arrangement chosen for signal path purity and mechanical isolation. The enclosure has no internal bracing, since Acora relies on the stiffness of the granite walls to limit reflections and cabinet vibration. The bass reflex loading extends the output of the small mid-woofer. Beyond the black Nero Assoluto granite, the Gemstone Series offers alternative stones, including salt and pepper Mystic Granite, Lilac Marble in translucent white and an Amethyst version of the SRB-Gem. Because the weight depends on the density of each stone, the finish chosen changes the mass of the finished speaker.

Pairing

With its wide recommended power window, the SRB-Gem accepts a broad range of amplifiers, from low-power valve designs at the bottom of that range to solid-state units. Its modest sensitivity means that higher listening levels are easier to reach with amplifiers toward the upper end of the recommended power span. A rigid stand able to carry a stone cabinet of this mass is needed, as the speaker is designed for standmount use.

Alternatives

The Acora SRB is the company's standard granite two-way standmount built around the same stone construction.