Logitech Z-5500 5 Speakers

This impressively large and powerful 5.1 speaker set boasts an integrated Dolby Digital/DTS/Dolby Pro Logic II decoder, and a THX certification indicating that it delivers sufficient sound quality for acceptable home-theater use. It consists of a subwoofer with built-in amplifier, 5 satellite speakers, and a control unit. I bought it because I wanted the Dolby Digital decoder, and I found the sound of smaller and less powerful computer speaker sets inadequate for either music or home-theatre use.

The subwoofer has a single 8-inch driver mounted in a black cubic enclosure with a bass port on the side. The 6-channel amplifier hangs off the back of the subwoofer, exposing hefty aluminum cooling fins to the air. It's nominally rated at about 500 watts RMS, but that's an inflated power rating using a 10% distortion figure - the real value (i.e., at clipping) isn't stated, but it's probably about 350 watts, which is still pretty respectable. The subwoofer is pretty hefty to lug around (no handles), and big enough that you might have trouble finding a spot to hide it around a computer desk. The heat sink gets warm when it has been playing loudly for a while, but never hot to the touch.

The 5 satellite speakers each have an identical single 2.5-inch driver. They are various shades of charcoal gray, looking quite handsome with or without the front covers in place. The drivers look like quality units - they have stiff paper cones in a rubber support ring, and each has a small metal cone protruding from the center which Logitech calls a phase plug - it's supposed to improve reproduction of the high frequencies. The center speaker housing is bigger and more horizontally-oriented, but strangely it's lighter than the others, and has two fake ports instead of one real one. Each satellite has a little metal stand with rubber feet, but the angle of the stand isn't adjustable. The stands are pre-attached, but removable with a little hex key (supplied). They can be reversed to act as wall mounts. The center speaker alone has a tripod screw-in socket on the bottom. Frequency response of the overall system is rated at 35-20,000 Hz (no +/-db range given, so take it with a grain of salt).

Now for the sound. In a home theatre application, listening to a DVD movie soundtrack like XXX with helicopters flying overhead and bullets whizzing past, these speakers are right at home. They can easily fill a medium-sized room with powerful sound. In computer games like Unreal Tournament the sound is tight, and delivers gut-thumping bass and percussive explosions. But there are few problems to iron out when it comes to playing music: out of the box, their overall frequency response is noticeably colored, the bass from the sub-woofer is WAY over-emphasized, and a couple of poorly-damped resonances are quite apparent. They can't be made to sound the same as a high-quality set of home stereo speakers. Still, they can do a pretty good job on most tunes * once they are properly balanced *. That means doing some work with a software equalizer on the PC, and with subwoofer placement in the room.

Since these 6 speakers and their amp cost less than even a moderately good pair of stereo speakers, a few shortcomings are not really surprising. The biggest fault is that the subwoofer is ridiculously over-emphasized, which makes the resonance it has in the upper-mid-bass particularly noticeable. There is a level control for the subwoofer, with about 20 steps. I wanted to set it on step 0.5 on the scale of 0-20, which unfortunately doesn't exist - 0 is off, 1 is already too strong, 2-20 are completely wasted. You may want to set the subwoofer somewhere off the floor and away from the wall to try to de-emphasize that resonance, which is not the easiest thing to do with a big heavy cube like this. On the computer you can also adjust the equalization in software - I have the equalizer set to roll off by about 9db (!) at 60 Hz to get a reasonable bass balance, and that's on the minimum subwoofer volume setting. I have visions that the guy that designed this at Logitech must listen to Metallica and Nine Inch Nails and not much else. On the other hand, the single-speaker satellite units do a good job on both mid-range and upper frequences, with none of the crossover problems associated with speakers that have separate mid-range and tweeter.

The sound opens up a bit in the 6-channel surround sound mode - it really does sound much better than stereo. The resonances are less apparent, as the sound is spread over more speakers. The music spreads out around the listener to form a nice 360 degree sound stage, although small changes in head postion can cause sudden shifts in apparent sound position. Once the speaker system is properly set up for 6-channel listening in the room, it actually sounds quite good, if a little bass-heavy. I've come to enjoy listening to rock and pop music the Z680s. The reserve power is readily apparent, as the sound is solid and undistorted at moderately high volume.

The surround-sound effect which the Dolby Pro-Logic II decoder can generate from a stereo signal is nice, but the default balance settings are not very good - be prepared to boost the rear channel way up and then play with the center spread to get it right. The sound environment parameters you can adjust on the control unit aren't explained anywhere, but if you're really curious, the Dolby Labs site has an explanation of all the Dolby Pro-Logic II parameters which are implemented by the Z680. To be honest, I found the computer's analog 6-channel surround sound settings better, and I ended up tuning the Dolby Pro-Logic II settings to match it as closely as possible.

I think the sound of these speakers could have been tuned a bit better out of the box, but overall the performance is in keeping with the price level and the primary intended purpose. The Z680 certainly sounds better than the less expensive speaker sets I compared it to (Creative Labs, Altec Lansing, and Logitech's own. I think the problem that other reviewers have distinguishing the musical limitations is that they aren't comparing the Z680 speakers side-by-side with reference speakers of good quality on a wide variety of music. I can put the Z680 side-by-side with my $300 Advent compact stereo speakers and hear that the Z680 speakers are colored and not quite as smooth. The Advents are intended for listening to music. They have a flatter frequency response which goes both higher and lower, with no harsh resonances. I can also switch to my $3000 full-range electrostatic panel speakers to verify what perfectly flat frequency response sounds like with the music in question (there's no comparison). You get what you pay for. The Z680 is good for its intended purposes. It's just not reasonable to call them "awesome" or "astonishing" when judged on overall musical sound quality.

To put to rest the frequent complaint of early purchasers of the Z680, this system does have some hiss, but it's not noticeable or objectionable with the current-generation control unit. I can't hear it over the sound of the computer fan with the center speaker 2 feet away. Mind you, any audible hiss is an indication that the design is not quite up to high-fidelity standards, but this isn't intended to be a hi-fi system, as noted above.

In the package you get 5 speaker cables for the satellites: 3 x 15 ft. and 2 x 6 ft.. These are probably too short for most rooms, but since it's pretty thin 20-gauge wire it's probably a good thing that they aren't too long. You can replace it with better speaker wire if you want a longer run. The ends are bare wire. At the speaker end you tighten a screw contact on them (or attach a banana-type plug if you prefer). At the amplifier end (and on the centre speaker for some reason) there are spring clips. This is all fine unless you are attaching and detaching frequently, in which case you might want more convenient integrated plugs. It would have been nice to have more apparent color-coding too - the wires are all brown, with the positive lead distinguished only by very faint markings.

Unfortunately Logitech cheaped out on the source connecting cables, at least in North America - no digital cables are included, but you do get a 6-foot length of 6-channel analog cables. Creative Labs includes optical and coax cables with their digital speakers. On balance I guess it's better that Logitech saved money on cables rather than the speakers - cables can always be added or upgraded separately later.

The decoder/control unit looks cool, although it seems big sitting on the desktop. It connects to the subwoofer with a 5-foot heavy cable ending in a 15-pin D-plug at the subwoofer end. (Logitech says that you shouldn't try extending it with a VGA cable extender, but with enough intelligence to verify that the extension cable has 15 straight-through pinouts it should be possible). The blue backlit LCD display has very low contrast, which makes it difficult to read. There's a big digital control knob in the middle of the front panel of the control unit used to set the various levels. You can independently set the overall volume and the level of the subwoofer (but see above), the center speaker, and the rear speakers, but you can't balance left-right or adjust the tone. The digital volume levels available are a bit coarse at the quiet end, but I didn't find that a problem as some other reviewers did. You can select from the 4 input sources on the the control unit: digital coax, digital optical, or analog 6-channel on the back, or the stereo auxiliary input on the front. Oddly the auxiliary input is mixed with the others rather than switched separately. There's a headphone jack on the front of the control unit, and the speakers mute when headphones are plugged in - but beware, volume level can be much louder than you expect when you unplug the headphones.

The display shows when a Dolby or DTS signal is detected on the digital inputs, and the "effect" and "settings" options offered change accordingly. Dolby Digital 5.1 surround sound from various movie DVDs was nicely reproduced on the Z680, whether plugged into the computer or the DVD player. A DTS soundtrack from a DVD was also recognized, although there were some glitches in playback (which could have been more to do with the DVD player software). Dolby Pro Logic surround sound was reproduced well from TV broadcast with the Z680 connected to the satellite TV tuner's digital output.

On the computer the sound was almost identical when switched between analog and digital inputs. Some other reviewers have reported significant differences, but I didn't detect any when all driver-applied effects were turned off. I do pick up a bit of high-frequency noise from the computer in analog mode at very high volume, but it's not really a problem. There were more audible clicks and pops when switching sources or changing between album tracks in the digital mode though - sounds like Logitech hasn't quite got the hang of muting the output while dealing with momentary digital glitches. The Logitech decoder accepts both 48K and 96K sample rates (unlike the low-end decoder in Creative Labs Inspire 5500D, which accepts only 48K).

The power cord is permanently attached to the amp on the subwoofer. The main amplifier power switch is on the back of the subwoofer. You can switch the unit to Standby from the control unit, in which case the system still consumes "a small amount of power" according to the manual, but it's not enough to make the amp or control unit feel warm.

The small infrared remote lets you control the levels, mute the audio, change input sources, test the speaker configuration, or cycle between effects. It runs on two AAA batteries (alkaline batteries included).

There's a manual in the box, but it's extremely sparse. It doesn't even explain what all the effects settings do.

Let's consider finally the subject of flexibility. The Logitech control unit has both its analog outputs and its power input (probably 12 volt?) somewhere in that 15-pin cable, but the pinouts aren't given, so you would have to do some work to adapt it for use separately from the amp. The decoder in Creative Labs' low-end digital 5500 speaker set has 3 analog output cables running from the decoder/control unit to the amp in the subwoofer. That's good in that you can use the decoder separately. On the other hand the Creative Labs unit has no 6-channel analog inputs on the decoder. That's bad - they expect you to plug 6-channel computer analog outputs directly into the subwoofer and give up the controls on the control unit. On balance, each has advantages and disadvantages, but both units could have been made more flexible.

Overall I think the Z680 strikes a good balance of price vs. performance for its intended market. The only outright criticism I would make is that the subwoofer level is so far unbalanced that it makes the level control useless. Also I would advise buyers whose primary purpose is to play music that they shouldn't expect the sound quality to be up to the level of a similary priced pair of stereo speakers.