Starting from the top of the audio spectrum and working our way downward, let me start by observing that Infinity's .75" tweeters produced treble response that was consistently crisp, clear, and articulate, helping to convey a sense of the "air" surrounding instruments, and giving the overtones of well-recorded strings, brass, and percussion a particularly pleasing, "silvery" sheen. Those treble characteristics also made the system especially good for film playback, helping to enhance dialog intelligibility and making the most of high frequency textural details and ambience cues in wellrecorded film soundtracks. My only criticism would be that—on certain hard, vigorous treble transients—the tweeters occasionally showed traces of edginess and brief moments of textural coarseness. On the whole, though, the system's treble response was very fine.
Next, the TSS-4000 system's midrange sounded open and transparent— direct benefits, I think, of the small, lightning-fast MMD drive units Infinity employs. These qualities were particularly noticeable and helpful whenever the system reproduced the sound of human voices, capturing subtle vocal intonations and inflections with ease. The TSS-4000 system also handled small textural details and other ambience and soundstaging cues very well, though I couldn't help but feel the big system somehow missed out on a bit of the magical and almost eerily three-dimensional sound that the little TSS-750 system had shown. Why the difference? I can't say for sure, but I think it might have had to do with the fact that the TSS-750 satellites were a smaller and simpler twoway design, whereas the TSS-4000 satellites are a larger and more complicated three-way design (one which just happens to have a 1kHzcrossover point that falls smack dab in the middle of the midrange). In any event, I remember that the TSS-750 satellites just got out of the way and "disappeared" into the broader soundstage, whereas the TSS-4000 satellites occasionally draw unwanted attention to themselves. Don't get me wrong; the TSS-4000 modules do a more than decent "disappearing act" of their own, but their soundstaging qualities aren't always as convincing as those of their little brothers.

However, the TSS-4000 satellite/center modules showed offsetting strengths in the area of dynamics, playing gracefully (even exuberantly) at volume levels where other compact lifestyle systems, the TSS-750 system included, would show audible signs of strain and compression. A significant benefit of the TSS-4000 system is that it offers sufficient output for use in fairly large rooms—rooms too big for modest surround systems to handle well. The TSS-4000 satellites also dispersed midrange frequencies broadly and evenly, a characteristic that helped output from individual channels coalesce into a smooth, continuous "ring" of enveloping surround sound. Great dispersion also meant that listeners seated well to the side of the traditional, central "sweet spot" nevertheless enjoyed fine surround sound imaging.
For the most part, midrange sound quality was good, but one area where I had some reservations involved the system's overall tonal balance. I found the balance was very subtly skewed such that the system's upper midrange sounded a little too forward while the lower midrange sounded correspondingly recessed. This deviation from tonal neutrality, though audible, was minor enough that most listeners would probably not find it distracting or displeasing, at least not at first. On the contrary, the slight upper midrange emphasis sometimes seemed a blessing in disguise, imparting a clear, incisive and exciting sound that often enlivened film playback. But for music listening the tonal balance was less pleasing because it made the system prone to excess upper midrange brightness, and introduced a slightly cold and withdrawn lower midrange sound that suppressed some of the natural warmth of instruments such as cellos. Setting aside the issue of tonal balance, however, I felt the TSS-4000 system's midrange offered compelling strengths.
The TSS-4000 system's bass was simply excellent (it was, I thought, the system's greatest single strength), especially when R.A.B.O.S. equalization was brought into the picture. What impressed me was that the subwoofer not only went down low with power and authority, but that it captured the timbres and textures of bass instruments with terrific clarity and finesse (a claim not all subwoofers could make with a straight face). I didn't realize just how capable the sub was until one evening when I played an old favorite film, Immortal Beloved [Columbia/Tristar], where there is a scene in which Napoleon's forces attack a villa where Beethoven is staying, leading the attack with rippling cannon fire. The cannons went off with a sharp and penetrating "Crraack… BooOOM," which the Infinity sub reproduced so cleanly and powerfully that it nearly launched me off my couch. Frankly, the subwoofer sounded as if it could have come from a more expensive system, which suggested to me that whoever handles subwoofer voicing at Infinity really knows their craft. R.A.B.O.S. helped, too, by taming room- resonance-driven boom and helped ensure the woofer could be optimized to perform well in virtually any room.