FBT SUBline 115S

SUBline: FBT's approach to the "stage-ready" passive subwoofer

The FBT SUBline 115S follows a clear philosophy: to offer a robust passive subwoofer with controlled sound, designed to easily integrate with an existing sound system. Its Italian manufacturing and birch plywood cabinet emphasize reliability and mechanical durability, two essential aspects when the subwoofer forms the foundation of a live mix.

Intended uses and target profiles

This subwoofer is designed for contractors, bands, and venues seeking a compact sub capable of supporting the kick drum, bass, and electronic sequences without overwhelming the space. With its 15-inch format and 98 dB sensitivity, the SUBline 115S is particularly suited for DJ setups, contemporary music, events, and satellite system reinforcement, where a solid and clear foundation is preferred over maximum size.

Performance, system integration, and design details

Bass reflex loading and 15-inch driver

The 1-way bass reflex configuration of the SUBline 115S is optimized to deliver effective bass across a range of 40 Hz to 140 Hz. The 15-inch driver equipped with a 3-inch voice coil is designed to handle sustained use, with an RMS power of 350 W and a Peak power of 1400 W, while maintaining controlled response.

Recommended settings: filtering and external management

To get the best performance from the subwoofer and protect excursion at the low end, a recommended high-pass filter at 35 Hz with a slope of 24 dB per octave is advised. The SUBline 115S is also designed for management via an external processor, with a recommendation to use an FBT DLM26 Digital Loudspeaker Management system for filtering and system tuning (specified crossover frequency: FBT DLM 26 ).

Speakon connectivity, stacking, and field practicality

The 2x Speakon NL4 connectors (input and LINK OUT) facilitate daisy chaining. For a classic setup with tops above the sub, the M20 threaded socket allows installation of a suitable pole mount. For handling, the cabinet features 2 ergonomic aluminum handles and can be equipped with a 4-wheel kit sold separately (KW-HM80), convenient for quick setups.

Technical specifications

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Model	FBT SUBline 115S	Voice coil	3 inches (76.2 mm)
Type	passive subwoofer	Frequency response	40 Hz to 140 Hz
Design and manufacture	Italian	Crossover frequency	FBT DLM 26
Manufacturer reference	41511	Recommended high-pass filter	35 Hz, 24 dB per octave
Configuration	1-way bass reflex	Recommended external filter	FBT DLM26 Digital Loudspeaker Management
Dispersion	omnidirectional	Nominal impedance	8 ohms
Recommended amplifier	700 W	Input connectors	2x Speakon NL4 IN and LINK OUT
RMS power	350 W	Cabinet material	15 mm birch plywood
Peak power	1400 W	Handling	2 ergonomic aluminum handles
Sensitivity	98 dB	Placement	4-wheel kit sold separately (KW-HM80)
Max peak SPL	135 dB	Installation	M20 threaded socket
Driver size	15 inches (381 mm)