PSB Speakers Alpha SubZero i review: PSB Speakers Alpha SubZero i

PSB Speakers Alpha SubZero i
Pint-size subwoofers sure have come a long way over the years. At one time, going small usually meant skimping on performance: baby-size boomers just couldn't muster much in the way of deep bass. Today, though, there are some exceptions, and PSB Speakers' spunky entry-level sub, the $329 list SubZero i, actually packs quite a wallop.

The i stands for improved. For starters, PSB doubled the power of the original SubZero, which we reviewed in 2001 and didn't particularly like. The new, built-in, high-efficiency amplifier delivers 100 watts of continuous power, 130 watts of dynamic power, and 260 watts of peak power. Further enhancements include antioverload circuitry, which allows the SubZero i to sail through short-term peaks and sustained high-power demands.

This sub, which comes in textured black or cherrywood-grain vinyl wrap, is really small, weighing 23 pounds and measuring 9.5 inches wide, 13.25 inches high, and 14.25 inches deep. Peek through the curved perforated metal grille, and you'll spot the SubZero i's 8-inch polypropylene woofer. You can't see the woofer's healthy 20-ounce magnet, but it's there, and it would normally wreak havoc with your TV if placed too close to it. Thankfully, however, the SubZero i is shielded, so you can put it wherever you want.

The front-mounted 50Hz to150Hz crossover and volume controls allow for easy adjustment (most subs have their controls tucked away on their rear ends). On the back, you'll find heavy-duty speaker level binding post inputs intended for use with older, pre-Dolby Digital receivers. That said, today's receivers will likely work best with the SubZero i's line-level RCA input. A bypass switch cuts out the internal crossover--the subwoofer then relies on your receiver's crossover, which distributes midrange and treble to the satellites and bass to the sub. That arrangement provides the smoothest possible integration between the sats and the sub.

The little guy is a solid performer--the SubZero i can get down and boogie in the 30Hz range. Yes, like most mini subwoofers, definition softens a bit, and it can turn a little boomy in its lowest ranges when the volume is pumped up. With some movie soundtracks, the extra boom enhances the experience. In tests, the heavy-duty assaults on the fiercest battle scenes in the Saving Private Ryan DVD sometimes overload baby subs, but the SubZero i never cried uncle. It really does sound like a much bigger sub.

As much as we enjoyed the SubZero i on DVDs, it really sang on CDs. It is, naturally enough, a synergistic match with PSB's little Alpha B satellites, and that was most obvious on acoustic music CDs. String bass had plenty of room-filling weight, and thanks to the SubZero i's crisp sound, it had no trouble rendering each individual bass note. Lesser subs have a tendency to blur bass instruments and drums, thickening their sound so that you just hear rumbling notes. The PSB can deliver fairly subtle low-down shading and nuances.