Recently purchased the LOGITECH X-540 5.1 Speaker System.

Why I purchased it:
We needed a SMALL system for our apartment, as we have downsized. I had purchased an inexpensive REGENT 2.1 system which was better than the Plasma TV speakers, but definitely not high fidelity.
Before downsizing, I had one of several good quality home theater systems, including an ONKYO 7.1 system which was my favorite by far. The sound was excellent. It was just too big for our apartment, so it is sadly gone.

I did not like many of the lower priced small theater systems out there. Many sound shrill, lacking bass, poor fidelity, poor detail, etc. So, I tried the LOGITECH X-540.

AMAZING SOUND:
The sound is very good. It fills my living room which is roughly 12 x 14 feet. Midrange is very smooth. This is so important. Many theater systems seem to lose midrange, making voice and dialogue hard to understand at lower volumes. Treble is excellent. Smooth and clean, not distorted or shrill. Very comfortable to the ears with no fatigue after long term playing. Bass is smooth. It is obviously not the bass of a large subwoofer, but it is very decent for its small size.

MATRIX SOUND: This is what sold me. Because my better half did not want a complicated-to-operate system, I connected this LOGITECH system to the LEFT/RIGHT audio outputs from my Plasma TV. All the components are connected to the TV via HDMI cables. With the MATRIX SYSTEM engaged, this LOGITECH system generates a very pleasant 5.1 simulated surround sound.
This MATRIX sound performs well with both DVD movies and MUSIC CDs. Listening to orchestral works was a real treat. The sound is smooth, full and fills the entire room. Detail is excellent. I can hear every nuance, much to my surprise. The strings of a violin being stroked and the breaths taken while playing a flute. Even the bass was remarkably full. While it cannot produce the true deep bass notes capable of rattling the floor boards, it can deliver the bass harmonics enough so as to give you a feeling of deep bass. This little sub can go quite low.

NO DISTORTION: My Plasma TV has variable output at its audio output jacks, allowing me to control the volume with my TV remote. I turned the volume up to about 65% and still NO DISTORTION at all. Very clean sound with no hint of stress.

CONNECTIVITY:
This system can connect to COMPUTER SOUND CARDS UP TO 7.1 output. This can also be used when connecting to a DVD player as well in some cases.
There are 3 stereo input mini jacks on the sub, which houses the amplifier. The first jack is for connection of a left/right analog output, as I described above. When the MATRIX switch is engaged, the sound is transformed to simulated 5.1 sound. Otherwise, it would be normal stereophonic sound.
However, by following the instructions, you can connect outputs from your PC to the other input jacks, thus creating DISCREET 5.1,6.1 or 7.1 sound. No need for a decoder as the sound is decoded from the source. If your DVD player has discreet 5.1 output jacks on the back, then I imagine you can connect those jacks directly to the LOGITECH, thus creating discreet 5.1 sound as well. You would need 2 more Y-cord connectors with dual RCA PHONO JACKS at one end and a stereo mini jack at the other. One such cord is supplied with this set.

BASS CONTROL: There is also a bass control on the subwoofer, just like in home theater system's subs. I have it set at the half-way point, which provides very smooth bass with no distortion.

A large volume control is also included. I have it turned all-the-way up. Depending on the output of your source, you may or may not need to do the same.

There is also a headphone jack as well.

SIZE: The sub is very small. Less than a foot high and deep and maybe 6 inches wide. It conveniently sits out-of-the-way, perfect for our apartment.

The speakers consist of 4x front/surround speakers each with dual tiny high-compliance drivers with cone-shaped domes which enhances the treble output and dispersion.

the center speaker is the same, except it sits sideways(horizontal), and its base is adjustable, allowing you to adjust the angle of the speaker. Or, it can sit on top of a LCD/PLASMA TV/MONITOR for better sound dispersion if required.

The front surround speakers also have built-in stands which allow it to stand upright, or be hung on a wall with professional looking results.

Speaker wiring is good quality and well insulated for lower noise. The speaker wire ends are RCA PHONO PLUGS, NOT STRIPPED WIRES as is the case with many home theater systems. This eliminates phasing errors caused by incorrect wires connections.

The controls are all located on the wired remote. NO WIRELESS REMOTE. The remote can sit on top of the sub.

All speaker stands and remote have felt feet.

Also comes with a cord consisting of 3 mini stereo plugs at both ends to be used to plug into the sub and a Y-connector with RCA jacks at one end and a stereo mini jack at the other end which I used to connect the RCA plugs from my TV to the sub.

SPEAKER WIRES ARE RELATIVELY SHORT. Especially for the set-up as I have described above. The center and front speakers have about 4-6 feet of speaker wire, each. The rear speakers have about 10 feet of speaker wire, each.

Because I mounted the rear surround speakers on the opposite wall, up high near the ceiling, I had to extend the wires. I did so by buying wires from RADIO SHACK. I bought 2 packs of 12 foot length wire, each with a RCA PHONO PLUG on each end. And I bought a pair of RCA JACK CONNECTORS which have a 'female' RCA JACK at each end. That is used to connect the speaker wires together. NO SPLICING. NO RUINING WIRES. Cost about $10 for the wires and connectors.

SUMMARY:
This system can deliver excellent sound. I am very impressed and very happy. I now can listen to my music CDs and watch DVDs with a feeling of high fidelity that I had missed since moving to an apartment.

DO NOT EXPECT TREMENDOUSLY LOUD SOUND OR EARTH SHAKING BASS.

Be realistic. The entire box of this system is smaller than many subs. Obviously, it will not deliver the deepest bass. However, it can deliver the harmonics which give you the sensation of deep bass. It reaches quite low. The sub driver is about 5 1/4 inches with a large excursion down firing cone, a poly or treated cone with a front firing tuned bass reflex port.

POWER OUTPUT is only 90 watts. I do not know what distortion rating or if it is true RMS output rated, but it sounds very good. It does state RMS, but that is it.
Approx 7 1/2 watts per front/surround speaker.
Approx 15 1/2 watts to the center speaker.
25 watts to the sub.

You probably won't annoy the neighbors with this system, unless you live in an apartment or duplex.

Other specs: 40Hz - 20Khz (I assume this is the approx speaker system range, but it can also be the amplifier range. I may write to LOGITECH and will edit this epinion if I learn more specific info.
5 1/4 inch subwoofer driver. 2 inch all other drivers.

If you live in a smaller space, and want a high fidelity system which can perform well with both movies and music, then you should definitely consider the LOGITECH X-540 speaker system.