Within what Polk calls an "anti-resonant" enclosure, the two-way TSi400 utilizes four Dynamic Balance® drivers - a 1-inch fabric-polymer dome tweeter with a neodymium magnet structure coupled to three 5 ¼-inch Bi-Laminate Organic Fiber cone woofers, crossed over at 2.5 kHz. Developed in conjunction with Johns Hopkins University, Dynamic Balance resulted from a laser interferometry research project that enables Polk to analyze the entire surface of a vibrating driver in real time, in order to determine the right composition of driver materials for the particular product. The TSi400 employs the rare downward-firing port, described as a "Critically Tuned Flared Port", which basically means that its design minimizes chuffing and optimizes bass response. The TSi400 provides two sets of gold-plated five-way binding posts for easy bi-wiring/bi-amping, and provides wide, fat stabilizer feet, which ensure stable coupling to hard floors or plush carpeting. While not as tailored as separate spikes or soft feet, they provide a nice down-the-middle solution for floors of all types and provide a distinctive look. Measuring 38.875 inches high by 7 inches wide by 14.25 inches deep and weighing 32 pounds, the TSi400 is not too big but has some meat on it (the higher weight may overload the feet with really plush carpeting, though, so beware). As with its two complementary models, the TSi400 offers a choice of ebony or cherry woodgrain finishes to complement its gloss black top plate, which adds an elegant touch. At $599.90 per pair (MSRP), the TSi400 offers an excellent level of fit and finish. The vinyl finish looks great (especially the Cherry), the meaty feet and connection panel fit nicely into the cabinet, the driver array offers clean seams, and the grill has nice rounded side edges.
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Sound
The TSi400 presents a nominal 8 ohm load with a 91db efficiency. It sounded good with average quality power sources, but overall needed better quality ones to sound its best.

The TSi400 threw a deep, wide soundstage with solid imaging and air around the loudspeakers. As with the smaller 300, the top end needed a bit more detail on rock and electronic material, but not quite as much. The top end meshed very well with the midrange and had a very appealing neutral character, although every now and then vocals sounded a bit canned and lacking overall warmth. The top end and midrange overall had a nice sense of pace and musicality. The bass offered some good punch and extended well enough for the size of the cabinet. Acoustic and classical material tended to sound better overall, although by no means did heavier material lack musicality. It thumped and sparkled enough to please most, but overall lighter material had a better balance and overall transparency. The TSi400 very much built on the strengths of the TSi300, adding a little low end and size, but not losing the littler model's very good top end/midrange. The TSi400 sounded a little better further away from walls, which kept its tonal balance from sounding too warm. The TSi400 played loudly when asked without much breakup, but needed better quality power to get there.

Competition and Comparison
Compare Polk's TSi400 loudspeakers against their competition by reading our reviews for the Boston Acoustics CS 226 and the Klipsch VF-36. There are more reviews available in our Floorstanding Speaker section.  To learn more about the company, visit our Polk Audio brand page.

Read more about the TSi400 on Page 2.