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Logitech Z623 review with technical data. I have just completed an extensive battery of tests on the Z623, using both subjective and objective methods. For the listening tests I used a number of audio sources (high bit rate MP3) ranging from dance music heavy with bass notes to vocals. For the measurement portion I used a signal generator and a sound level meter. The sound level from each of the sources, the subwoofer, the port, and the satellite speakers was added together mathematically. I am including the plot of the response as a user image. First the aesthetics and user friendliness of the system. The power cord comes into the woofer box, then a thick heavy control/signal cable goes to the right speaker and a thin signal only cable goes to the left speaker. Since the cables are permanently attached to the speakers, it would have made sense to make them a bit longer than the 6ft each that they are. Of course with the control cable being > .25" thick, it would have ben somewhat unwieldy to move around. Both the woofer box and the satellite speakers are a subdued black industrial design with the speakers having prominent bolting to make them look real heavy duty. While the box is a straight lines only cube, the satellites also feature smooth organic lines all around. The controls located on the right speaker are smooth, power button activation is light but you still have to hold the speaker to keep it from tipping over. The bass level knob has a detent in the center of travel, which indeed proved to be an optimum position to balance the highs and the lows. The listening test and measurements: I used an Ipod as a music source and quickly observed that you had to turn the Ipod sound level about all the way up to get a good range of loudness from the speaker volume control knob. For the bass heavy tests I used tracks by 2 Unlimited, Lady Gaga and Pitbull. For the vocal tests I used Jewell, Adele and Decemberists. The bass heavy tracks were rendered with very good low extension, and this can be seen from my response curve. From my established refrence point of 95 db, the Z623 can be said to have a real world frequency response of 30-20kHz, although this comes at a very liberal +/- 10 db tolerance. The peak response at low frequencies was at 40 Hz, which while not typically thought of as a boomy frequency (60-90 Hz) still came across as not being as tight as I would have liked. The midrange is silky smooth, but not very accurate. You can see that essentially from 300 to 8kHz it is increasing in amplitude. What this results in is a smooth sound that lacks presence. Comparing this system to my Altec iMT800 boombox quickly reinforced my very positive opinion of the Altecs. All of the midrange of the Z623 appeared in one flat plane, while the Altec reproduced the soundstage in a crisp 3 dimensional projection. This is where you can not only locate the singer and all the instruments left and right, but front and back as well. This can be alleviated somewhat if you use "emphasize treble" on the sound settings of Ipods or a treble boost from the Volume control panel on the computer. The Z623 does not have a treble control on the speaker, bass level only. After the peak in the response curve at 8kHz, the response start dropping off continuously up to 20kHz and this is what you have to compensate for to get any semblance of crispness that seems to be lacking a bit. In summary the Z623 system is not only a very capable, loud computer desktop system, but it also fills in the audio reproduction function very nicely as well. While it may not be the most accurate speaker, with some minor treble adjustment it can be used as a good stand alone system with any MP3 players or flat screen TV's.