|  Logitech
has introduced their new THX® certified Z-5500 5.1 speaker system that includes
both DTS and Dolby Digital decoding capabilities in a single package for under
$400. The Z-5500 replaces the award-winning Z-680 5.1 system and includes five
satellite speakers, a subwoofer with built-in power amplifiers, the SoundTouch™
Control Center, wireless remote and cables. Total power output is 505 watts RMS,
188 of which are dedicated to the subwoofer. If you think this is a lightweight
package, you'll be surprised to find out that the boxed system weighes nearly
60 pounds . The Z-5500 has a frequency response from 33 Hz - 20 kHz with a signal-to-noise
ratio of 100 dB (typical) according to the manufacturer. The SoundTouch™
Control Center accepts analog and digital inputs and performs all the audio processing
within the main console. The low-level analog signals are then sent to the subwoofer
chassis over a seven foot cable where multi-channel power amplifiers reside. Each
of the satellite speakers uses a 3" polished aluminum phase plug driver in
a ported enclosure. The well built, ported subwoofer cabinet includes a 10"
high-excursion ported driver. The system is designed to satisfy music and movie
enthusiasts as well as PlayStation®2 and Xbox® gamers. Based on our tests,
we think they have succeeded in all areas.
 Design
The brains of the Z-5500 reside in the Digital SoundTouch™ Control Center
where the digital processing takes place. The easy to read high contrast LCD display
provides the user with all the information needed to operate the system. Five
buttons control the functions allowing the user to select the input, modify the
effects, change the settings, trim the levels and mute the audio. The large weighted
knob on the front panel work well and is used to change the appropriate setting
when selected. The power button on the lower right illuminates orange when in
standby mode and turns blue when the system is powered on.
Inside
the SoundTouch™ Control Center lies a Cirrus CS494003 32-bit DSP to handle
both Dolby® Digital and DTS® bitstreams including DTS® 96/24 data
for unsupassed sound quality. A Cirrus CS42526 data conversion chip is used to
move signals between the analog and digital domains. The CS42526 contains an amazing
number of high-quality converters including six 24-bit DACs and two 24-bit ADCs.
The same chip includes digital audio interfaces (S/PDIF) used for the coaxial
and optical digital connections. Finally, a pair of Cirrus CS5351 stereo ADCs
are also used to convert the remaining analog inputs to the digital domain. Cirrus
has an excellent reputation among audio enthusiasts and their products are commonly
found in some of the best audiophile equipment. We were glad to see Logitech has
chosen to use them in their Z-5500 product. The result is a great sounding 5.1
system with features found in more expensive products. The
rear panel of the SoundTouch™ Control Center has inputs for both coaxial
and optical digital signals. Three stereo analog inputs are also located on the
back allowing the Z-5500 to benefit from a 6-channel sound card installed in the
PC. Setting the 2-position switch to "6 ch direct" setting will pass
the analog signals straight through without any decoding. A seven foot cable with
three 3.5mm male stereo connectors at each end is provided to interface to a six-channel
PC sound card. Our setup utilized an M-Audio Revolution 7.1 audio card. There
is also an auxiliary input jack located on the side of the console for convenient
connection of portable devices such as CD or MP3 players.  The
easy to read LCD on the SoundTouch™ Control Center has a pleasant backlight
that displays the input and effects settings when the system is in idle mode.
Whether the room lighting is good or bad, you won't have a problem seeing the
display on the console. During level adjustments, bargraphs are used to show the
setting. If the input signal contains 96/24 DTS data, the display will indicate
this in the upper right corner with "96..24".
 Speakers
The Z-5500 THX® approved speakers produce great sound considering each speaker
only has a single driver in the ported cabinet. The removeable black cloth grill
neatly covers the front of the speaker and helps protect it from dust and possible
damage. Even without the covers the speakers look attractive. The rotating pedestal
stand allows each speaker to be table or wall mounted. The center channel offers
even more flexibility allowing the user to direct the speaker towards the listener.
Amazingly, the 3" drivers used in each of the five speakers include rubber
surround material instead of the cheap foam surround often found in less expensive
speakers. We were impressed to see this in the Z-5500 system. This system uses
what Logitech calls digital equalization, which sounds like a good marketing
name for active equalization to compensate for frequency response non-uniformities.
Remote
 The
wireless remote included with the Z-5500 was a handy addition to the system. The
Power button turns on the system and is indicated by the blue LED on the
front of the console. The Test button verifies that each speaker is properly
connected. Pink Noise is generated in 2.5 second intervals in the following order:
Left Front, Center, Right Front, Right Rear, Left Rear and Subwoofer. Dedicated
buttons for the Optical and Coaxial digital inputs are provided. The Effects
button selects the sound effects and the Settings button adjusts the corresponding
parameters. The Mute and Volume Up/Down buttons control the volume
level. Separate Sub, Center and Surround level buttons are
provided that make it easy for the user to adjust each speaker to the appropriate
level. The Direct button selects the analog inputs and if the two-position
toggle switch is set to the Stereo 1-3 mode, pressing the switch will cycle through
the three sets of analog inputs.  The
rear panel of the subwoofer chassis uses color coded RCA connectors for each of
the five satellite speakers. A high density 15-pin connector interfaces to the
Digital SoundTouch™ Control Center over a seven foot cable where it receives
the analog signals processed by the console. A master power switch and fuse holder
occupies the lower part of the panel along with the non-detachable power cord.
We were impressed to see the large heatsink fins used to cool the amplifier modules
contained within the subwoofer chassis. Each speaker has its own amplifier circuitry
and shares a common heavy duty power supply. Due to the power rating of this speaker
system and the linear amplifier design, a significant amount of heat can be generated
when driving the system hard. Logitech has taken measures to ensure that heat
can be properly dissipated by the power electronics when required. We took a look
inside the subwoofer chassis and were pleasantly surprised to see good build quality
and internal cabinet bracing. The port design uses smooth edges to prevent wind
noise through the port at low frequencies. The
power supply design in the Z-5500 has a large toroidal transformer with two 10,000
µF capacitors to store energy for the power amplifier rails. This is something
that one might see in a more expensive product, but is certainly not typical in
a PC-based speaker system. We must commend Logitech for using such a hearty power
supply design in this system.
Performance
The Logitech Z-5500 is a great product that surpasses any of the PC-based speaker
systems we've tested to date. The design, performance and user interface is sure
to please. This system is ideal for those who use their PC for both music and
movie watching. This 5.1 speaker system produces great fidelity at good loud levels.
Bass was great and provided a level of impact that was very satisfying. The satellite
speakers did a good job at reproducing music as well as movie dialogue. We
liked the flexibility of this system and its ability to accept both analog and
digital inputs. Making use of our existing 5.1 audio card had its benefits, but
we were not limited in any way to use the digital connection with the Z-5500.
Once engaged, the digital decoder displayed the format detected and produced great
sound. The ability to trim the levels of the satellites and subwoofer made for
an overall better sounding system. Since all the satellites used the same type
of driver, sound panned seamlessly between channels giving a more realistic experience
when sound engineers move the audio around the listener. The wireless IR remote
is a feature and allowed us to lean back and still fully control the system. Conclusion
Logitech's THX® certified Z-5500 has proven to be a great performer and offers
features that we would rate as highly desirable. The design of the SoundTouch™
Control Center user interface is attractive, feature rich and simple to use. There
is plenty of power available in the system to produce satisfying levels of music
or movie soundtracks with audio quality not expected from a PC-based system. The
Z-5500 is designed to accommodate virtually any common digital format with the
ability to decode Dolby Digital, DTS and PCM bitstreams. If your system already
benefits from a six channel sound card, then the Z-5500 can accept three stereo
line level analog signals as well. In fact, the cable for this application is
included. While
the Z-5500 system is not inexpensive for a PC-based 5.1 audio system, it is by
far one of the best sounding PC systems that we have heard to date. The THX®
certification is more than just a fancy name attached to this system. The certification
does ensure a level of performance that many PC-based systems could never achieve.
If you really want to experience impressive sound quality with your PC audio whether
it be for music, movies or games, the Z-5500 will likely put a big smile on your
face. -
Kevin Nakano | 
