The SB 300 system's initial wireless subwoofer pairing is achieved by pressing the "pairing" buttons on both the sub and sound bar. The sub has two control knobs on its rear panel (volume and "subwoofer cutoff control"), both of which permit finer tuning of the system's bass balance than you can do on most sound bar/subwoofer systems.
JBL doesn't offer any specific guidance for setting the subwoofer cutoff control, which is traditionally known as a subwoofer crossover control. The range of crossover frequencies is continuously adjustable from 45 to 200 Hertz, and we used 200Hz for all of our listening tests. There's one other control, a "phase" switch with two positions, 0 and 180 degrees, and in most cases the 0 position will produce the smoothest blend between the speaker and sub. While all the adjustability is nice, note that changes can only be made on the subwoofer, so you can't control the subwoofer level from the remote.
All of that probably sounds more complicated than it is: pair the sub and bar, turn the cutoff control to its max position, put the phase switch to 0 degrees, adjust the subwoofer's volume to taste, and you're good to go. (It would have been nice if the manual said as much.) We recommend placing the sub within 4 or 5 feet of the sound bar to get the best possible sound.
Performance: Bigger sound bar, bigger sound
It didn't take too long to hear what separates the SB 300 from all of the smaller and less expensive subwoofer-sound bar systems: the JBL is considerably more refined and powerful-sounding. Sure, that big sub is responsible for the gravitas advantage, but the sound bar also exhibited above-average resolution of fine detail. The SB 300 delivered more of the visceral excitement in the "Inception" Blu-ray than any subwoofer-sound bar system we've tested since the Harman Kardon SB 16. (Harman and JBL are both subsidiaries of Harman International). It's not just a coincidence that both systems feature large subs and sophisticated sound bars.
The "Quincy Jones: The 75th Birthday Celebration - Live at Montreux" DVD sounded awfully nice. The stereo soundstage spread wide across the front wall of the CNET listening room, but this is strictly a two-channel system. Herbie Hancock was playing a funky keyboard slung over his shoulder as the band laid down heavyweight grooves. We noted that the blend between sub and sound bar wasn't perfect, so some bass notes were lighter than others. The drummer's cymbals had more sparkle and detail than your average sound bar would allow. This level of deep bass prowess and top-end resolution elevate the SB 300 to the top rank of integrated two-channel systems.
We still had the Harman Kardon SB 16 on hand, so we compared it with the SB 300 while watching the "Black Hawk Down" Blu-ray. The wide dynamics swings and power required to convey the fiery helicopter crash and battlefield explosions were impressively played by both systems. As we listened more, we felt the clarity of the gunfire exchanges on the city's streets was a wee bit better with the SB 16, and the low rumble of the large military vehicles had more low-end weight on the SB 16 too. But the differences between the two systems weren't major, and both sound a lot more powerful than any other subwoofer-sound bar systems we know.
Switching to stereo music, Radiohead's "OK Computer" CD sounded a little bright on the SB 300. Thom Yorke's vocals and the guitars were too thin, but there's no way to adjust the sound bar's tonal balance. At this price, JBL should have included bass and treble controls, or at least a few preset EQ options (rock, jazz, acoustic, and so on). On the other hand, bass definition and power on The Dead Weather's "Sea of Cowards" CD were excellent. In short, the SB 300 can play louder than most sound bars, but it's still better suited to movies than music.
Conclusion: A good deal, if you can tolerate the look
If your main concerns are sound quality and value, the JBL SB 300 is a great pick, delivering most of the performance of the Harman Kardon SB 16 for less money. Just make sure the SB 300's style is right for your living room, as it tends to stick out more than blend in.