ETX-15SP from Electro-Voice is a powered subwoofer; 
it can be used in a variety of portable and permanent applications. The DSP (Digital Signal Processing) menus offer extensive configurations, crossovers, true cardioid presets, protection limiters, EQ mode, and a lock out mode that prevents casual changes to the system. 
 
Loudspeaker system performance is optimized via an LCD screen.
The front LED indicates power or can be configured to indicate limit. EV’s FIR-Drive technology utilized the latest FIR (Finite Impulse Response) filter technology to optimize transducer linearity and advanced limiter algorithms for independent peak and thermal transducer protection.
 
True cardioid DSP preset delivers true cardioid response across all frequencies. The enclosure is constructed out of 18-mm plywood finished with EVCoat.
Subwoofers include professionalgrade castors, and combination pole mount receptacle for threaded and unthreaded loudspeaker poles. ETX Powered Loudspeakers combine EV-engineered intelligent DSP, high-powered amplifiers and high-efficiency transducers to deliver that legendary EV sound and performance. System overview Subwoofer amplifier panel: 1. LCD 2. MASTER VOL/DSP
 
High-Sensitivity, Low-Distortion Transducer Design
All ETX woofers use Faraday rings for better vocal reproduction
The woofers not only have high power handling but also feature a robust mechanical design to ensure long-term reliability
EV focuses on engineering transducers with linear frequency response, minimizing the need for additional equalization
 
Components and Testing
All ETX components are designed from the ground up by Electro-Voice. No off-the-shelf components are used
The handles, pole cups and amplifier chassis are die-cast aluminum, not plastic
18mm, 13-ply birch plywood with EVCoat is used throughout the ETX product line
In addition to industry-standard pink noise abuse tests, all models must survive EV's proprietary 1,000-hour torture test that uses real-world signals driven beyond full output
 
Processing and Control
System DSP presets support quick and easy setup via selections for type of use, crossover frequencies and top/sub combinations
Includes a DSP preset for "true cardioid" configuration
ETX employs the same proprietary PAL and TEMP limiters developed for Electro Voice's concert loudspeakers
Boundary compensation filters are included so that an ETX loudspeaker sounds the same whether it is used as a floor monitor, on a tripod or suspended from a ceiling
ETX offers user-adjustable features including delay out to several hundred feet, three-band parametric equalization, polarity and multiple high-pass crossover points
The Class-D design of the amplifier is designed to be efficient and features blower-controlled thermal management, allowing it to work in hot environments. The fan is of a quiet design and does not turn on under normal circumstances
Lockout mode helps prevent casual users from changing settings
 
LCD Interface
Complete full-function DSP control via a single-knob interface. LCD screen for easy system set-up and monitoring: location/application EQ presets, limiter status, input level controls/meters and master volume control to ensure optimal gain structure
 
Features
1800 W amplifier and 134 dB peak SPL  
Single-knob DSP includes presets for multiple configurations and top+sub combinations (performance style, locations, and space)
 Loudspeaker system performance monitoring via integrated LCD and front panel LED
 Includes DSP preset for true cardioid performance
Enclosure includes removable casters and a combo pole cup (insert and threaded) for use with the two-way models