Unlike the Yamaha Digital Sound Projector single-speaker systems, the SurroundBar 50 doesn't rely on wall reflections and room acoustics to generate surround effects. Instead, the speaker produces its own surround ambiance, with an updated version of Polk's patented "SDA Surround" technology (Stereo Dimensional Array) that first appeared on the company's speaker systems in the late 1980s. SDA Surround technology uses signal processing to produce "virtual" surround sound and can also work in stereo. We did note it works best when we were at least 6 or 7 feet away from the SurroundBar 50.
We started our listening sessions with our new favorite demo, the Sunshine Blu-ray disc. The sci-fi space-mission-to-the-sun flick is loaded with explosions and deep bass sounds, and the SurroundBar 50 (and its companion subwoofer) passed those torture tests with flying colors. The sound was remarkably pure and clear, much more so than what we've experienced with the Yamaha YSP-3000 single-speaker surround system.
That said, the SurroundBar 50's handling of the film's surround sound was good, but not as three-dimensionally developed as what we heard from the Yamahas. The Polk's soundfield is wide and had a nice sense of depth, but it never came forward or out to the sides of the CNET listening room like the Yamaha YSP-3000 or 4000. Likewise, the SurroundBar 50's spatial effects work best for listeners seated directly in line with the speaker--the "surround" sound collapses back into the speaker for listeners seated off to the right or left side of our couch. (By comparison, the YSP-3000's surround effects were more uniformly projected throughout the room.)
The Rolling Stones Four Flicks DVD set's full-blown rock and roll made us sit up and take notice. The skinny SurroundBar 50, ably assisted by the Polk PSW111, didn't pull any punches so the Stones sounded live, and we could hear the concert venue's ambiance and space. Resolution of fine detail was quite good, and Mick Jagger's vocals were very natural, without any of the hard/thin quality we complained about when we reviewed the original SurroundBar and the Yamaha YSP-3000. No, the new speaker's warmer, fuller tonal balance is more to our liking. The sound held together, even when we pushed the volume way up.
The House of Flying Daggers Blu-ray Disc made even greater demands in the Polk system, especially when we played our favorite circle of drums scene. The big drums sounded plenty big, and each thwack on the skins was clear and distinct. Still, the surround limitations were noticeable: effects never encircled the CNET home-theater room as they do when we've played the Blu-ray on full 5.1-channel systems.
We knocked the original SurroundBar's sound with CDs, but the new speaker and subwoofer combination was equally strong on CD as it was on DVD and Blu-ray. Stereo separation stretched well out to the sides of the speaker. Rock, jazz, and classical music were all well served by the SurroundBar 50.
To finish up, we compared the SurroundBar 50 with the similar Definitive Technology Mythos SSA-50. We listened sans subwoofers to better ascertain the differences between the two. In the end, we felt the two soundbars were closely matched, but the SSA-50 was somewhat more "full range," and therefore less dependent on the subwoofer. The Polk and the Definitive are both very, very good soundbars, but we'd give a slight edge on sonics to the SSA-50. That said, the Polk wins points for that fact that it's slightly more affordable and offers a better assortment of included accessories (color-coded speaker wire, table stands).