My Velodyne HGS-15 is crossed at 80 Hz. It blends seamlessly with my KEF 104/2s, generates that subtle vibration you feel at a pipe organ recital when a big pipe is opened, and can make you feel pressure on your chest during explosions in certain flicks. With a 15 inch woofer, 1200 watt DC amp, and huge motor, it meets Shadorne's specifications. In my application, a 19 X 14 X 8 room, an Auralex SubDude base greatly improves the sound, removing boom and seeming to extend the low end. But it is a 100 pound cube when you want to move it.
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