7. Sophisticated Technology

• Z-4 2.1 Speaker System...
• • ABT
  • $99.00

The Z-4's satellites have no protective grille, and so reveal what look like three fairly large microdrivers. In fact, it appears that it's actually one small loudspeaker, approximately 2" (5 cm) in diameter, with an inverted-dome cone and a large half-roll suspension, and two passive speakers (called "pressure drivers" by Logitech) equipped with flat membranes and half-roll suspension.

Since disassembly was impossible, we weren't able to look inside to see what makes them tick, but it's obvious that the (sealed) load volume is shared. The satellites are mounted on very well-designed solid metal feet, but the angle isn't adjustable. On the other hand, the base, held on with two screws, can be removed to mount the satellites on the wall on a round-headed screw.

The subwoofer employs a technique often used by Logitech: symmetrical loading with a passive membrane. The active speaker is mounted on an interior partition, and the actual sound emission is via a passive membrane (with an 8" diameter!). Aside from being more attractive-the visible speaker is larger-this technique has the advantage of extending the bass response into the lower frequencies in a smaller subwoofer volume. On the other hand, its downside is poor reproduction of transients. The results need to be judged in terms of what kinds of music and what style of sound reproduction are most important to you.