Hsu VTF-3 MK 3 Turbo ($799; without Turbocharger, $699; Turbocharger purchased separately, $199)

What's in the Box? • Driver: 12-inch • Rated amplifier power: 350 watts continuous • Cabinet design: side-firing, dual rear ports • Finish: black or maple • Controls: level, continuously variable low-pass crossover (24 dB/octave, 30 to 90 Hz), crossover bypass, phase switch (0, 180 degrees), bass extension (1 port open or with Turbo 18Hz, 2 ports open with no Turbo 25 Hz), auto-on/on switch • Ins & outs: dual line-level inputs, dual speaker-level inputs and outputs • Warranty: 7 years (2 years on amplifier)

How Big Is It? • Dimensions (WxHxD): subwoofer, 17 x 22 x 25 inches; Turbocharger, 17 x 10.5 x 11.5 inches • Cabinet volume: 5.5 cubic feet • Footprint: 3 square feet • Weight: subwoofer, 90 pounds; Turbocharger, 25.5 pounds

Setup When subwoofers start nudging the 100-pound mark, you certainly don't lift with your back -- and you don't lift with your legs, either. You have someone else lift it. Better yet, don't lift it at all; slide it across the carpet. The VTF-3 MK3 is imposing, all the more so with the Turbocharger that either inspired The Blue Man Group or was inspired by it. The Turbo is a passive device with tubes that connect to the VTF-3's ports, lengthening them and effectively doubling port volume to extend low-frequency output. Controls are straightforward, with no line-level output and a simple two-position phase switch. The low-pass crossover reaches up to about 90 Hz, which is high enough to blend with most satellites. This is a side-firing design, so take care to avoid jamming the driver right up against a wall. (Interestingly Hsu suggests placing the sub so the driver faces into the back of your sofa, with 1 or 2 inches of spacing, to provide good upper bass that is hard to localize.) Similarly, keep in mind that the Turbocharger ports face perpendicularly to the driver, another thing to think about before you start dragging the subwoofer around the carpet.

How Low Does It Go? • Bass limit (with Turbocharger): 16 Hz at 83 dB SPL (maximum 10% distortion)

How Big the Bang? • Average maximum output, 25 to 62 Hz (with Turbocharger): 105 dB SPL • Maximum output (with Turbocharger): 109 dB SPL at 50 Hz • Dollars per dB: $7.61