|  Logitech
has recently introduced their new X-540 speaker system designed to give users
a full surround sound experience with a set of five satellite speakers and a dedicated
subwoofer. The system includes stereo matrix processing that is designed to create
spacious surround sound from two-channel audio sources. A unique feature offered
with this system is a center channel that can be placed on top of an LCD flat
panel display. Logitech has an integrated patent-pending center-channel clip that
securely attaches the speaker to the monitor, so it will not wobble or slide off.
This not only looks good and saves space, but also places the center channel sound
right above the screen for the best experience when watching movies or playing
computer games. Amazingly, this system retails for under $100.
The
Z-540 comes with a trio of stereo cables designed to interface with popular 6-channel
surround cards found in many multimedia PCs. Each cable is color coded to make
it easier to identify the cables on both ends. If only a two channel source is
available, the matrix surround processing can be engaged for a simulated surround
effect much like the old Dolby Surround processing. If a game console is being
used, Logitech includes an adapter that accepts RCA phono plugs and converts them
to a female 3.5mm stereo jack designed to mate to the main audio cable.  Center
Speaker Clip
One of the best features offered with the X-540 speaker system
is the ability to mount the center speaker directly above the flat panel display.
It places the center audio right where it needs to be, close to the screen action.
This is especially important when watching movies or playing video games and adds
another level of realism to the experience. It is possible to get a similar effect
using the right and left speakers to create a center image, but to have this work
well it is highly dependent on the placement of the user's head. The center speaker
has four rubber pads, two located under the cabinet and two on the front lip,
both of which as designed to keep the housing from sliding around. This also provides
some damping to prevent vibration or buzzing when playing the audio loud. The
base, which also includes a long rubber pad, mates to the back of the display
and accommodates various screen thicknesses while keeping the speaker cabinet
perfectly straight. This innovative speaker clip design can also work as a standard
stand to accommodate good old-fashioned CRT displays.
 Speakers
The front and rear pair of speakers feature a swivel base that twists 180 degrees
and allows them to be mounted on a wall or sit on a table top. Each speaker has
two small drivers and comes in a sealed enclosure. I did notice that the top driver
emits higher frequencies than the lower driver. My curiosity got the best of me
and soon I had the speaker open to figure out why. As it turns out, the speakers
are wired in series with one another. The lower driver has a 33uF capacitor across
the terminals which is designed to limit high frequencies emitted from it. Most
likely this approach prevents the speaker from sounding too thin. The design essentially
uses two drivers for lower frequencies and transitions to a single driver as frequencies
increase. The implementation works surprisingly well and the sound produced by
these rather small drivers was impressive. As with most small satellite speakers,
the crossover frequency is on the high side to help prevent a frequency gap between
the satellite speakers and the subwoofer. Having a high crossover frequency can
sometimes cause the subwoofer to sonically appear in the soundstage.
 Wired
Remote
The wired remote connects to the subwoofer cabinet through a long
extension cable. The power button is on the left side and the button on the right
is used to enable the matrix circuit. Each button has a LED to indicate status.
The large knob on top is the master volume which controls the volume of all the
speakers including the subwoofer. The small control between the buttons is the
bass level, designed to work with the main level control. There is also a 1/8"
headphone jack that will automatically mute the audio to the speakers when headphones
are plugged in. The volume level is very easy to control with this remote and
provides a smooth level change.
Performance
The Logitech Z-540 offers excellent sound for the dollar with clear midrange and
smooth bass response. Moderate volume levels produce very enjoyable sound from
the rather cheap audio electronics found in our PC. We easily heard a significant
improvement in sound quality when we used an outboard HeadRoom Desktop Amp
feeding the X-540 system. This outboard DAC produced far more detail than the
DAC found in our stock computer system. This was good news and proves to us that
the X-540 can produce even more detail when fed with higher quality audio. Similar
results were revealed when using the Revolution 7.1 audio card from M-Audio. The
advantage of using a 5.1 sound card such as the Revolution 7.1 is the audio is
fully discrete with sources that support the format such as movies and games.
So many users use cheap speakers with their PC that computer manufacturers pay
little attention to the audio quality. The
center speaker did a great job at reproducing movie dialogue with the DVDs we
played. We liked how tightly coupled this speaker was to the LCD screen, immersing
the viewer into the video content. Logitech´s so-called Frequency Directed
Dual Driver™ technology works well even though the name appears to have fallen
out of the marketing department. Having identical speakers for each of the five
channels helps to seamlessly pulls the audio together as sound pans from one channel
to the next. Conclusion
Logitech's X-540 5.1 speaker system is a real value with a price below $100. Any
computer system with low quality speakers will immediately benefit from the 5.1
channels offered by the X-540.
The system will significantly
improve the sonic experience of music, games and movies. The matrix decoder works
well and adds depth and virtual surround to any two channel source. The center
channel speaker design is both innovative and provides a practical solution to
getting sound as close as possible to the video monitor. We have heard no other
system priced under $100 that offers the features and sound quality found in the
X-540 system. -
Kevin Nakano | 
