Полочная акустика — JBL SUMMIT AMA

The Summit Ama is the smallest of the three Summit loudspeakers from JBL, a two-way design for stands, sitting in a series, completed by the three-way Pumori and Makalu, and it was engineered at the JBL engineering centre in Northridge, USA. It is sold in pairs with matching stands, at a list price of USD 19,995, GBP 14,998 or EUR 17,490 per pair.

Key specs that matter

JBL fits a D2815K compression driver with a 38 mm throat, two diaphragms and two motors, and the diaphragms are made of Teonex, a polyethylene naphthalate resin. Below it sits a 200 mm bass and midrange driver with a 64 mm voice coil and a three-layer cone of hybrid carbon and cellulose composite. JBL rates sensitivity at 84 dB at 1 W and 1 m and nominal impedance at 4 ohm. Response is 34 Hz to 25 kHz at the minus 6 dB points and 25 Hz to 33 kHz at minus 10 dB. The cabinet measures 476 mm high, 308 mm wide and 336 mm deep and weighs 26.3 kg, and a rear-facing reflex port handles bass loading.

Engineering and use context

The compression driver loads into an HDI horn moulded from Sonoglass, a dense fibreglass-filled resin, shaped to control dispersion vertically as well as horizontally. This horn assembly alone measures roughly 25 x 20 x 20 cm and weighs more than 3 kg. The crossover splits the band at 1.6 kHz with third-order slopes, a low point for a compression driver of this size. Instead of a few large capacitors, the MultiCap network uses a larger number of smaller ones, which lowers equivalent series resistance. The cabinet is built from sustainably sourced engineered wood with an irregular octagonal cross-section, offset multi-point internal bracing and heavy damping. Rhodium-plated binding posts accept a single cable or separate runs for bi-wiring and bi-amping. The supplied stands combine steel and aluminium, weigh about 20 kg each, route cables internally and stand on isolation feet developed with IsoAcoustics, so a speaker on its stand exceeds 45 kg. Finish choices are ebony veneer in high gloss trimmed with gold or high-gloss black with platinum trim.

Pairing

The low sensitivity and demanding nominal load call for a high-current solid-state amplifier. Through the bi-amp capable terminals an owner can drive the woofer and the compression driver from separate amplifier channels.

Alternatives

For a far smaller JBL stand-mount with a compression driver, the Studio 630 uses a 165 mm PolyPlas woofer, a 1.9 kHz crossover and a cabinet weighing 9.02 kg.