Atlantic subwoofers use the same design approach in all their subs to produce consistently realistic, convincing bass effects. Their subs may vary in how loud they’ll play and what size room they’re most suited to, but never in quality. Big room or small, from loud to soft, the sound quality of an Atlantic Technology subwoofer is always top-notch.The Atlantic Technology 642e SB THX Select powered subwoofer is a significant upgrade from its highly acclaimed predecessor. Compared to the original 642, they have developed a totally new driver with three times the motor size, a stiffer spider, and a heavier cone. It’s a real “monster” of a driver. While the driver’s free-air resonance remains at 25 Hz, the output of the sub from 35 Hz to 60 Hz-right in the impact range- has been improved by almost 3dB.They’ve modified the equalization (because of the new driver’s improved low-frequency output, less amp power is needed for EQ, and consequently more power is available for SPL), limiting and soft clipping parameters of the amplifier to optimize its performance. The result of these changes is a perceived 50-watt increase. In other words, the amplifier plays louder than before, with less distortion at its limits. The 642e SB features a sealed enclosure design for low distortion and smoother bass output. Sealed enclosure woofer designs are inherently low in distortion, and deliver deep smooth bass response with a gradual and predictable roll-off below resonance. As with all Atlantic Technology subwoofers, close attention has been paid to providing accurate musical bass reproduction along with terrific special effects. Atlantic’s proprietary Clear Filter Technology™ ensures that the bass is detailed and accurate.