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Alpha 425 FS

Twin 15" Flying Subwoofer
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Product at a Glance

The Alpha 425 FS is twin 15” High Output Subwoofer that provides a powerful and extended low frequency response with ample headroom. It’s optimal enclosure design allows for very low port compression and delivers a tight and accurate bass response which is ideal for touring & high-performance installation applications.

The Alpha 425 FS houses two ultra-long excursion 15” ultra-low distortion drivers. A 4” voice coil ensures a linear excursion of 20mm at a steady magnetic force. The Alpha 425 FS can be integrated into flown arrays or ground stacked systems with the Alpha 428LA Line Arrays. The amplification, networking & signal processing come from the dedicated XD Racks or X Racks.

The Alpha 425 FS was primarily designed as a low frequency extensions woofer with the LFE-GS preset. There is also a LMB-F preset for use as a flying subwoofer with the Alpha 428LA. With the options of a cardioid or omni-directional presets, the Alpha 425 is suited for touring and install applications where high precision, optimal dispersion control and deep bass is needed.


Painstakingly Perfect Production

Over the years, craftsmanship has been closely linked with small scale individualistic production. Back in 1972, we started the same way. As we grew in scale & size, it was difficult to build each speaker individually, but quality control was of utmost importance as so switching to a general assembly line was simply not an option. So we wrote up a code, one quite like enigma, to ensure quality control. We selected the right partners, got the right tools, and in cases where those weren't available, we invented them. We grew slower than most as our aim was to last longer than most. 

Tech Specs



Frequency Response (-3 dB)

31Hz - 150Hz

Frequency Range (-10 dB)

26Hz - 150Hz

Rated Power

1600W Continuous, 6400W Peak

Maximum SPL

138 dB Peak (LFE-GS Preset)

Coverage Pattern

Omnidirectional, Cardioid Presets Available.


Nominal Impedance

8 Ohms

Rigging Compatibility

Alpha 428LA, Alpha 425 FS & Delta 25 4FS


Marine Birchwood Cabinet, Premium Grade


Powder-coated durable grill with acoustically transparent foam

LF Driver

15” Ultra Low Distortion Woofer, 4” Voice Coil, 800W AES.

Crossover Frequency

100 Hz (requires active crossover in DSP)


British Acoustics' Signature Brown Finish

Mounting System

Integrated 4 point Rigging System with Lock-n-StockTM Mechanism


2 x Neutrik® NL4 on rear, 1x NL4 front-grill mounted; all wired parallel









51 Kgs

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We have a growing network of channel partners

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