Полочная акустика — JBL JBL 4309

The JBL 4309 is a two-way passive monitor for shelf or stand use in the Studio Monitor family, launched by Harman in 2021 at USD 2,000 or GBP 1,799 per pair. JBL modelled it on the bigger 4349 and set out to deliver that speaker's performance in a smaller cabinet, keeping the horn-loaded compression driver and the blue front baffle that mark the family. Owners get a 5-year warranty.

Key specs that matter

A J165P-4 woofer of 6.5 inches (165 mm), with a pure-pulp cone in a cast frame, works below 1.6 kHz. Above that point a 2410H-2 compression driver takes over, using a single 1-inch annular Teonex diaphragm and a neodymium magnet behind an HDI horn. JBL quotes a frequency range of 42 Hz to 30 kHz at -6 dB and a sensitivity of 87 dB measured with 2.83 V at 1 m. Nominal impedance is 4 ohm, and the maker suggests amplifiers delivering 25 to 150 W RMS. Each cabinet stands 419 mm high, 260 mm wide and 227 mm deep with the grille fitted and weighs 10.98 kg.

Engineering and use context

Behind the pulp cone sits a 1.5-inch voice coil with 1 inch of peak-to-peak excursion, a vented pole piece, a symmetrical field gap and copper and aluminium shorting rings. The horn profile was computer-optimised for consistent output from 2 kHz to 17 kHz, so that off-axis response tracks the on-axis curve. Enclosure walls are 18 mm thick, with V-bracing placed using FEA software to curb panel vibration, and the reflex system vents through two flared front ports shaped to keep airflow laminar. In the crossover, the high-frequency section uses air-core inductors and film capacitors, while the woofer section uses a steel-laminate core inductor. A UHF control on the front panel under the horn changes the level between 7 kHz and 20 kHz. Twin pairs of gold-plated binding posts joined by shorting straps take one speaker cable or separate feeds for bi-wiring and bi-amping. Walnut and black walnut satin veneers are offered, each with a matching cloth grille.

Pairing

A 4309 needs solid-state electronics that stay stable into such a load, and the suggested power window covers most integrated designs of that type. Owners of two stereo power amplifiers can feed woofer and compression driver separately through the split terminals. Harman names the L10cs Classic Series subwoofer as a partner for the 4309 when extra depth is wanted.

Alternatives

The JBL 4349 is the larger passive Studio Monitor behind the 4309, pairing a 12-inch woofer with a D2415K dual 1.5-inch compression driver.