Полочная акустика — PMC BB5-A SE

The BB5-A SE is the active version of the BB5 SE from PMC, The Professional Monitor Company of Britain. The SE range has its roots in the three-way reference monitors PMC builds for recording studios. In the active form each speaker is matched with PMC amplification and active crossovers built for this specific design, instead of relying on a passive crossover network.

Key specs that matter

The three drive units are a PMC 380 mm (15 inch) Radial bass driver, the PMC75 75 mm fabric dome midrange and the PMC34 34 mm soft dome tweeter. Crossover points sit at 380 Hz and 3.8 kHz. The quoted response is 17 Hz to 25 kHz, and the ATL (Advanced Transmission Line) behind the bass unit is 4 m long in effective terms. Each channel receives 900 W for the low frequencies, 300 W for the midrange and 300 W for the tweeter. Connections are a balanced analogue XLR input and a Neutrik NL8 socket. The cabinet is 1040 mm high, 432 mm wide and 790 mm deep and weighs 87 kg, and the matching stand adds 19 kg.

Engineering and use context

With ATL the bass driver sits at one end of a long, damped internal channel that is folded inside the cabinet and opens through a vent on the front. The line lets the rear output of the cone reinforce the lowest frequencies rather than being absorbed, and this is what allows the response to extend so low. PMC states that its active electronics are hand-built according to analogue principles and coupled directly to the drive units, giving the amplifiers tighter control over each driver and a more efficient transfer of energy than a passive crossover allows. The tweeter was developed specifically for the high power handling of the active SE models, and its acoustic lens alone took 18 months to develop. PMC offers a 20-year warranty when the speaker is registered within 10 days of purchase.

Pairing

Since amplification and crossovers are supplied by PMC, the owner only needs a source with balanced outputs and a preamplifier or streamer with volume control, such as a DAC with a variable balanced output. The passive BB5 SE uses the same drivers and cabinet with three pairs of 4 mm sockets for tri-wiring or tri-amping, and is rated at 92 dB sensitivity with a 4 ohm nominal load. For multichannel systems PMC makes a dedicated BB5-C SE centre model.

Alternatives

The PMC MB2-A SE is the mid-sized active model of the SE series, using a 12 inch Radial bass unit with 325 W for the low frequencies.