Review: Polk Audio Blackstone TL350
Since time immemorial (or at least the late 1980s), designers of compact subwoofer/satellite speaker systems have struggled against The Hole.
The Hole is the gap between the lowest note the satellites can play and the highest notes the subwoofer can play. The Hole can make voices sound thin, and can rob gunshots and other sound effects of their dynamic impact. But the usual methods for filling The Hole can cause worse problems than The Hole itself.
Armchair engineers might suggest simplistic solutions like making the satellite play lower or the subwoofer play higher. But if you make the subwoofer play higher than about 100 Hz, you may start to hear voices come out of it. If you make the satellite play lower, either you’ll push its little woofer into distortion or you’ll have to switch to a bigger woofer and/or enclosure — in which case your cute little sub/sat system isn’t so cute anymore.
The Blackstone line represents Polk Audio’s all-out assault on The Hole. The company even trademarked a tag line for it: The Return of Big Speaker Sound Without the Big Speaker®. Granted, the fact that a trademark-happy company registered yet another tag line isn’t news, but you can tell from the design of the new TL3 satellite — the top model in the Blackstone line — that Polk’s engineers worked even harder on this one than the lawyers and marketing guys did. For a $149 satellite speaker, the TL3 looks like serious stuff. It’s the first inexpensive satellite I’ve seen with a ring-radiator tweeter, a feature more common to $5,000-per-pair speakers. Its 3.25-inch woofer has a real aluminum phase plug affixed to its center pole piece. (Speakers at this price often have a dust cap misleadingly shaped and plated to look like a phase plug.) The plug smoothes the high-frequency response of the driver and also helps cool its motor structure. The tweeter is set back to align its acoustic center with the woofer’s, a feature I’ve seen on countless high-end speakers but on no other tiny satellite speaker I can recall. Polk adds its PowerPort on the lower back of the satellite to reinforce the bass.
Polk’s engineers shaped the steel-reinforced molded enclosure to minimize resonance and vibration. The grille functions as part of the acoustical design, with an integral waveguide that helps the woofer and tweeter blend better. The TL3 can be placed on a stand or shelf, and includes a threaded socket compatible with standard wall mounts.
To expand the TL3 into a home theater system, you can add the TL3 Center Channel, which is basically a horizontal TL3 with a second woofer. The TL350 package, which combines four TL3s and one TL3 Center Channel, saves you $50 compared with buying the products separately.
You also need a subwoofer; Polk recommends its new DSWpro550wi. Packed with proprietary blahblah and patented yada-yada, the DSWpro550wi would have excited me no more than any other 10-inch, 400-watt, $500 sub except for the presence of the Polk Room Optimizer. The PRO provides four EQ presets to optimize the sub’s response for its position in your room. Your options are Cabinet, Corner, Mid-wall, or Mid-room placement, each selectable from the sub’s remote control. PRO won’t give you the precision of an auto-optimization or parametric EQ function, but it’ll get you at least part of the way there.