Logitech Speaker System Z520
Just a few years ago, 2.1 speaker systems--those that use small, left and right satellites for higher frequencies plus a larger subwoofer/amplifier component that sits under your desk and produces lower frequencies--dominated the computer-speaker market. But over the last few years, 2.0 systems--which comprise slightly larger left and right speakers, with the amplifier housed inside one of those speakers--have become popular again. A compact 2.0 speaker system takes up less space overall, but it usually doesn't provide the same kind of bass punch as a system with a dedicated subwoofer.
The Speaker System Z520 is the flagship 2.0 system in Logitech's latest line of computer speakers. Each speaker is just over 9 inches tall, 4.8 inches wide, and 6.5 inches deep (not including the cables that protrude from the back, which add about another inch to the depth of the right speaker).
The speakers' plastic cabinets sport a matte, dark-gray finish in back and on the sides, with a glossy-black front. Silver accents around the speaker drivers are visible only if you remove the system's black, metal grilles. Behind each grille sit a 0.75-inch tweeter and a 2.75-inch lower-frequency driver. I preferred the look of the grille-less speakers, although the holes for the grille's attachment posts are noticeable with the grille removed.
On the front of the right-hand speaker is a large, comfortable power/volume knob with an amber LED indicating both power and, by its position on the knob, the current volume level. On the back of that same speaker are jacks for connecting the left speaker (via the included six-foot cable, which is permanently attached to the left speaker) and the system's power brick. There's also a permanently attached, five-foot cable with a stereo miniplug at the end for connecting the Z520 to your computer. If your computer is farther than five feet from the right-hand speaker, you'll need to get an extension cable.
On the right side of the right-hand speaker are two handy minijacks: a stereo input for connecting a second audio source, such as an iPod or iPhone, and a headphone output for private listening. The headphone jack's output is controlled by the Z520's volume knob, and the Z520's speaker output is automatically muted when you connect headphones.
Finally, on the back of each speaker, directly behind the front-facing tweeter, is a second tweeter that projects audio to the rear. Logitech claims this second tweeter allows the Z520 to produce "360-degree sound"--not surround sound, but rather audio that sounds as good from the back of the speaker as from the front. The idea here is that the system can be used in rooms--an office or a kitchen, for example--where the speakers may be in the middle of the room rather than up against a wall.
The design of the Z520 is attractive as computer speakers go, and the speakers themselves feel solid and well-built--they're surprisingly heavy, in fact. Each speaker is also angled upward significantly so that when placed on a typical desk, the tweeters will be aimed directly at the ears of the listener. (Of course, if you place the speakers higher--say, on a monitor stand or a bookshelf--this design means the tweeters will be aimed above your ears.)
The overall sound quality of the Z520 is pretty good for a two-piece system, offering clear detail, decent midrange, and some bass punch. (The system provides solid low-frequency performance to just below 100Hz, with bass output declining significantly by 80Hz and gone completely by 65Hz.) And with 26 Watts of power, the Z520 can easily fill a bedroom or office with loud, no-distortion audio.
Where the system falls short is in tonal balance--a common shortcoming of 2.0 systems. The treble detail often sounds a bit forward compared to the midrange, and the lower mids and upper bass frequencies are pronounced. The latter characteristic is especially noticeable at louder volumes, where the speakers can sound boomy. (The Z520 doesn't include hardware bass or treble controls.)
What about the "360-degree sound"? I was pleasantly surprised by how good the system sounds from behind and to each side. Because higher frequencies are quite directional--the farther you get from being directly in the "line of fire" of the audio source, the more detail you lose--most speakers don't sound good as you move to either side, and sound even worse from behind. But the Z520's dual, opposite-facing tweeters mean that when positioned behind the speakers, you're hearing the same treble output as someone in front. And when you're off to the side, the fact that you're hearing off-axis audio from both tweeters means you're able to hear those higher frequencies more clearly than if there was only one tweeter.
On the other hand, because the higher frequencies produced by the Z520's midrange drivers are also somewhat directional, the sound from behind or to the side of the speakers still isn't quite as good as the sound when positioned directly in front. In addition, when the speakers are placed close to a wall--for example, when your desk is against a wall--you can at times hear the audio from the second set of tweeters reflected off that wall. This reflected audio sometimes creates a sense of additional space, but other times creates an unnatural effect.
Overall, the Speaker System Z520 is an innovative and well-designed set of computer speakers. The speaker enclosures are sturdy and attractive. The bi-directional design means that if the speakers are positioned in the middle of a room, you'll hear relatively constant audio quality nearly anywhere in that room. And the large, comfortable volume dial and easily accessed second-input and headphone jacks are great for usability. However, like many compact speakers that attempt to produce full-range audio, the Z520's tonal balance has its flaws, especially at louder volumes.