Setting up the GT5051 set is a snap. You simply position the center (4 by 6.5 by 4.5 inches, HWD) and satellite (8 by 4 by 3.5 inches) speakers on your desk, stash the subwoofer (12.5 by 7.5 by 9 inches) underneath, connect the speakers to the amp located in the subwoofer, then connect the remaining cables to your PC soundcard (a Sound Blaster Audigy 2 ZS Platinum Pro, in our case). Although you need a 5.1-channel sound card to get true surround sound with the GT5051, a switch on the subwoofer accommodates sound cards and other sources with as few as two channels, thanks to a technique called upmixing, which distributes the sound to every speaker. Unlike some higher-end systems, such as the Logitech Z5500, the GT5051 is analog only--you get no digital audio inputs, so you'll need a digital receiver as a go-between if you want to add a game console or a DVD player. There's a stereo RCA analog auxiliary input on the subwoofer, as well as a miniplug input for connecting a device such as an iPod. Altec Lansing hid a headphone jack on the back of the right satellite speaker, a convenience also offered by numerous competitors.
You'll find a volume wheel, as well as small subwoofer and center, surround, and power buttons on the top of the right speaker. In the volume wheel's default mode, it controls the overall system volume, but pressing a speaker button lets you adjust the levels of specific speaker channels in the mix. Blue status LEDs denote the volume level and the speaker channel-selection status. Because they're mounted flat on the top of the relatively tall speaker, the LEDs are hard to see, and they're essentially useless when you're seated at a computer desk.
The left and right speaker boxes are essentially two speakers in one. Each enclosure includes a front-firing 3-inch driver on the bottom and a side-firing 3-inch driver on top. The front-firing driver plays the front-channel signal, while the side-firing driver plays the surround channel signal. Effectively, the front-firing drivers deliver direct, focused sound the way standard speakers do, while the side-firing drivers produce diffuse sound to emulate the effect of dedicated surround speakers. Similar dipole speaker designs have been used for years in home-theater systems.
Altec Lansing rates the GT5051's total system power at 80 watts, 30 watts of which push the subwoofer's small, 5.25-inch driver. That's a reasonable amount of power output for this price range (compare to the 75-watt total output of the slightly less expensive Logitech X-530 5.1 set). The 10 percent total harmonic distortion (THD) rating (as provided by Altec Lansing) is a very high rating of signal noise compared to the 0.1 percent we've seen from some higher-end speaker sets. It's also interesting that because vendors can measure THD at different volume levels, we've seen other speakers with a 10 percent THD rating (such as the Creative GigaWorks ProGamer G500s) that sound, for the most part, just fine. In the case of the Altec Lansing GT5051s, they must have measured at a lower volume setting, because as you crank the dial, the sound output loses clarity.
With the GT5051 set up and ready to rock, we fired up Half-Life 2's deathmatch mode. Although we can't say the pseudo-surround sound helped us track enemies any better, the sound characteristics of various game environments sounded convincing. The story was the same with the Jurassic Park DVD. The GT5051 expanded the sound field's breadth, but we couldn't pinpoint audio that should've sounded like it was coming from specific locations. Frankly, we've experienced a similar level of sonic envelopment from 2.1-channel speaker sets that use surround-sound simulation technology, such as Logitech's excellent Z-2300. The GT5051's midrange performance gave Half-Life 2's machine-gun blasts a convincing metallic rattle, but the ported subwoofer couldn't deliver much palpable bass with either movies or games. As a result, rocket and grenade explosions in Half-Life 2 and the huge dinosaur's footsteps in Jurassic Park lacked the adrenaline-stoking kick you'd get from a more powerful subwoofer. The center speaker delivered dialog clearly enough, but it didn't stand out as well as numerous other centers we've heard, including the aforementioned Logitech Z-5500 Digital.
During music tests, we found that the GT5051 sounded best with the surround-sound drivers muted or set very low in the mix, because they tended to give music a tinny, nasal quality. Vocals in Nina Simone's "Plain Gold Ring" even made the surrounds glaringly break up at only a moderately loud volume level. Overall, the GT5051 just isn't a very natural-sounding music system; midrange sounds seem hollow and treble frequencies lack the smoothness you'd get from better speakers. What's more, the small subwoofer can't deliver enough distortion-free low-end sound to really deliver hip-hop or other bass-intensive music.