Low-pass Filter 500 Hz

High-pass Filter 3500 Hz

3-way Crossover 500 Hz/5000 Hz

3-way Crossover 500 Hz/3500 Hz

2-way Crossover 800 Hz

2-way Crossover 5000 Hz

Low-pass Filter 250 Hz

2-way Crossover 3500 Hz

2-way Crossover 2500 Hz

D-fend™ Loudspeaker Protection

The patent pending D-fend technology utilized within the SA300 stand-alone unit makes use of advanced, high-efficiency power conversion techniques to provide an unprecedented level of protection for your loudspeaker system. Due to the architecture of the D-fend technology, the SA300 is the first device within the industry to provide programmable, high-voltage, high current, full range signal protection for large loudspeaker systems.

In the past, protection circuits were employed only for use with high frequency devices due to the limited power handling of the protection circuits. These devices attempted to protect the high frequency driver by dissipating the undesired power into resistive elements or even light bulb components. Obviously, these power dissipative passive techniques resulted in limited power handling characteristics, no user programmability, limited response speed, no frequency selectivity, and life-cycle concerns. D-fend overcomes these deficiencies and provides you with the first-ever full-range, programmable loudspeaker protection network for use within a myriad of applications.

This technology operates upon the principle of reducing the power delivered to the load, your loudspeaker, while also reducing the net electrical current required from your amplifier. In other words, the D-fend technology is a non-dissipative technique in that it does not dissipate the undesired power into heat or light output; rather it reduces the amount of power that is requested from the amplifier through the use of high-efficiency digital factoring. Obviously, we believe D-fend is groundbreaking technology that opens a door for users such as yourself to experience peace of mind concerning your loudspeaker investment. With the D-fend digital attenuator under complete microprocessor control, you have at your fingertips a world of protective configurations.

Broadband protection of a loudspeaker or loudspeaker system

By enabling the All Pass function, one can set the maximum average power level that the device will see. As with all D-fend applications, the Attack and Release times can be adjusted to facilitate natural sounding speaker protection.

High frequency protection

RMS and Peak power can be limited to prevent thermal and mechanical failures of high frequency devices.

Low frequency protection

Woofers and subwoofers carry the burden of the most demanding loads in audio. By properly choosing peak limits, one can maximize the performance of these devices by preventing over-excursion events and heating issues.

The following plots illustrate how D-fend™ can be programmed to match a loudspeaker’s power handling characteristics, including both response time and required attenuation levels.

Passive Crossover for BMS4590L 2 Coaxial Driver 150 W + 80 W + 8 Ohm