FBT J15

FBT J15: A Classic 15-Inch Format Speaker for Sound Reinforcement

The FBT J15 is aimed at those looking for a passive 15-inch speaker, appreciated for its ability to produce generous low-end while maintaining solid projection. Its 2-way Bass Reflex configuration combines a 15-inch woofer and a 1-inch tweeter, a widely used combination in sound reinforcement to achieve a balanced sound capable of handling both playback music and live sources.

What Uses Is the FBT J15 Designed For?

Thanks to its 90 deg (horizontal) x 60 deg (vertical) dispersion, the J15 is suitable for front-of-house sound reinforcement in a simple setup (pair of speakers), as well as more complete systems with subwoofer(s) as needed. It is particularly well suited for bands, DJs, associations, multipurpose venues, and providers seeking a reliable passive speaker that is easy to power and deploy.

With a nominal impedance of 8 ohms and a RMS power of 150 W, it pairs naturally with a suitable power amplifier. The manufacturer recommends a 300 W RMS amplifier, providing a comfortable margin for peaks and improving dynamic handling, provided good setup practices are followed (limiting, reasonable equalization, and appropriate filtering).

Acoustic Design and Key Points for Field Use

A 2-Way Bass Reflex System Designed for Impact and Clarity

The 15-inch woofer (2-inch voice coil) provides solid low and low-midrange support, while the 1-inch tweeter (1-inch voice coil) delivers the precision needed for vocals, transients, and details. The 1.8 kHz crossover frequency contributes to coherence between the two drivers, ensuring a balanced sound suitable for both music playback and speech.

Controlled Coverage and Easy System Integration

The 90 deg x 60 deg directivity helps target the listening area while limiting unwanted side projections, an advantage both in rooms and on stage. On the connection side, the 2 Speakon NL4 inputs facilitate daisy-chaining and integration into a speaker fleet, with secure wiring suited for intensive use.

Filtering Recommendations to Protect the System

To optimize power handling and limit unnecessary excursions in the sub-bass range, a recommended high-pass filter at 40 Hz with a 24 dB/oct slope is advised. This is particularly relevant if the J15 is used at high levels or in configurations aiming to preserve amplifier dynamic headroom.

Technical specifications

Model	FBT J15	Nominal impedance	8 ohms
Type	passive speaker	Frequency response	50 Hz - 20 kHz
Color	black	Sensitivity	99 dB
Manufacturer reference	37833	Maximum peak SPL	127 dB
Configuration	2-way Bass Reflex	Recommended high-pass filter	40 Hz - 24 dB/oct
Woofer	15 inches (381 mm), 2-inch (50.8 mm) voice coil	Input connectors	2 x Speakon NL4
Tweeter	1 inch (25.4 mm), 1-inch (25.4 mm) voice coil	Enclosure material	polypropylene
Dispersion	90 deg H x 60 deg V	Mounting	2x M10 + 35 mm pole mount
Crossover frequency	1.8 kHz	Installation	adjustable mounts sold separately (BOX 112)
RMS power	150 W	Dimensions	663 x 410 x 387 mm
Peak power	600 W	Weight	14.7 kg
Recommended amplifier	300 W RMS