The sub's 10-inch, down-firing driver is coupled to a highly efficient 200-watt amplifier, which is said to provide 420 watts of dynamic power. It's worth noting that Klipsch's power ratings conform to the more rigorous FTC rating standards, so--unlike the wildly optimistic wattage ratings ascribed to most subwoofers--the Sub-10's potency is assured.
The subwoofer's low-pass crossover is continuously adjustable from 40Hz to 120Hz. Connectivity covers all bases with stereo-line and speaker-level inputs, plus a set of speaker outputs (the speaker connectors are all heavy-duty binding posts). A dual-color blue/red LED display on the front of the subwoofer lets you know whether the unit is on or in standby mode. And while a knuckle rap to the cabinet proved it to be fairly hollow and resonant, we didn't detect that in its sound.
We used the Sub-10 with a pair of Klipsch's new Synergy SLX satellite speakers. The SLXs sound great, but since they produce virtually no mid- or deep-bass on their own, they're totally dependent on the sub to flesh out the sound. The Sub-10 was mostly up to the challenge, but we had to invest quite a bit of time fiddling with its crossover and level controls to achieve a satisfactory blend with the SLXs. The subwoofer rolled out supple bass on CDs and massively deep impact on special-effect-laden DVDs. But most of the time, we weren't all that aware of the Sub-10's contributions--it took something along the lines of a car crash or an explosion (requiring low-end support) for the Sub-10 really to kick in and shake up our home theater. While the Sub-10's bass is gutsier and clearly more powerful than the last sub we tested, the Wharfedale SW150, bass-hungry listeners may not be satisfied. Upgrading to the 12-inch Klipsch Sub-12 could provide your SLX system with more bass bravado.