Polk Audio CSi 40 Center Channel Speaker (Black)
Polk Audio CSi 40 – Review The Polk Audio CSi 40 is a classic centre-channel speaker from Polk’s earlier generations of home-theatre products. Designed primarily to handle the most important part of a movie soundtrack—the dialogue—it combines a substantial cabinet, dual 6.5-inch drivers and Polk’s Dynamic Balance technology to deliver a presentation that is considerably bigger and more authoritative than many compact centre speakers. Although the CSi40 is now a discontinued model, its combination of size, sensitivity and full-bodied sound means it can still be an excellent choice for a carefully matched home-theatre system. Design & Build Quality The CSi40 immediately gives the impression of being a serious centre speaker. Its relatively large cabinet provides the internal volume needed for the two 6.5-inch drivers to produce convincing lower-midrange energy. The black wood-grain cabinet on the example shown here has a distinctly early-2000s Polk appearance. It is not particularly minimalist by modern standards, but it has a solid, purposeful look that suits a traditional home-theatre system. Around the rear are conventional speaker terminals and the large enclosure is designed to sit horizontally below or above a television or projection screen. One of the CSi40’s greatest advantages is simply its physical size. Compared with smaller centre channels using 4- or 5.25-inch drivers, the CSi40 has considerably more ability to move air. Driver Configuration The speaker uses a pair of 6.5-inch Dynamic Balance mid/bass drivers flanking a central tweeter. This configuration gives the CSi40 plenty of cone area for a centre-channel speaker. That extra driver area is particularly useful for male voices, action movies and soundtracks containing substantial mid-bass information. The CSi40 is also capable of playing at respectable levels without sounding strained, making it particularly well suited to medium and larger rooms. Sound Quality Dialogue Dialogue is where a centre speaker either succeeds or fails, and the CSi 40 does this very well. Voices have a substantial, natural character rather than the thin or nasal quality that can sometimes affect smaller centre speakers. Male voices in particular benefit from the CSi40’s larger drivers, while female voices remain clear and articulate. The result is a centre channel that gives dialogue a good sense of weight and presence. Rather than making voices excessively bright to create the impression of detail, the CSi40 has a smoother, more relaxed presentation. Crutchfield similarly characterises its overall sound as warm. Movies This is where the CSi40 really comes into its own. Explosions, effects and music are given considerably more authority than you might expect from a conventional centre speaker. The larger drivers help create a broad and substantial front soundstage. One of the advantages frequently noted by Polk users is the step up in scale from smaller models such as the CSi30. Polk Audio forum members have specifically described the larger 6.5-inch drivers as providing a bigger front soundstage and more impact. The CSi40 is particularly enjoyable with action films, where gunfire, engines, explosions and soundtrack effects can become much more dynamic. Music While the CSi40 is primarily a home-theatre speaker, it can also perform surprisingly well with music. Its tonal balance leans toward the warm and full-bodied side rather than being aggressively analytical. This makes it pleasant for vocal-heavy recordings and live concert material. However, this isn’t a speaker I’d choose as a dedicated high-end music speaker. Its real strength is reproducing the centre information in a multichannel system. Bass Performance For a centre channel, the CSi40 has impressive low-frequency capability. The larger cabinet and dual 6.5-inch drivers give it considerably more low-end authority than compact centre speakers. Polk forum discussions from the period frequently highlighted the CSi40’s stronger bass and fuller presentation compared with smaller centre models. That said, in a modern home-theatre system I would still recommend using bass management and a good subwoofer rather than asking the CSi40 to reproduce the deepest frequencies. Crossing the centre over to a capable subwoofer allows the CSi40 to concentrate on what it does best: vocals, dialogue and the midrange. Tonal Character The CSi40 has a distinctly smooth, warm and substantial character. This is both a strength and something to consider when matching it with other speakers. Some Polk enthusiasts have noted that the CSi40 can sound more relaxed than later RTi/CSi models. In discussions comparing the CSi40 with the later CSi5, users often described the CSi40 as having a smoother overall character, while the CSi5 could sound more open and somewhat brighter. For listeners who dislike bright or aggressive home-theatre systems, this can actually be a major advantage. Matching Matching the CSi40 with the rest of your system is important. Ideally, the centre channel should have a similar tonal character to the left and right speakers. The CSi40 was commonly associated with Polk’s earlier speaker ranges, and pairing it with speakers from a similar Polk generation can produce a more seamless front soundstage. If you mix it with a significantly brighter modern speaker, you may notice a tonal difference when sounds pan from the left speaker through the centre and toward the right. What I Like Large, substantial cabinet Dual 6.5-inch drivers Excellent dialogue intelligibility Warm and smooth presentation Strong midrange and mid-bass Impressive dynamics for a centre speaker Good performance at higher listening levels Excellent value when purchased used Particularly enjoyable for movies and TV What Could Be Better Large and relatively bulky Styling is unmistakably from an older generation Not the most neutral or analytical centre speaker Tonal matching is important Modern centre speakers can offer better dispersion and refinement Its age means condition should be carefully checked when buying used Verdict The Polk Audio CSi 40 is a very good example of an older centre-channel speaker that has aged well. It doesn’t have the refinement or technological sophistication of Polk’s latest centre speakers, but it gets the fundamentals right. The large cabinet and dual 6.5-inch drivers provide a sense of scale that smaller centre speakers simply struggle to reproduce. Most importantly, dialogue is clear, natural and substantial, while movie effects have enough weight and dynamics to make the CSi40 feel like a genuine part of the front soundstage rather than simply a speaker dedicated to reproducing speech. For someone building or restoring an older Polk-based home-theatre system, the CSi40 remains a compelling option. If you find one in good condition at a sensible price, it can deliver a big, warm and powerful cinema experience without requiring a huge investment. Overall Rating: ★★★★☆ 4/5 Sound: 4/5 Dialogue: 4.5/5 Bass: 4/5 Dynamics: 4.5/5 Build: 4/5 Value Used: 4.5/5 Bottom line: The CSi40 may be an older Polk, but its large-scale presentation, excellent vocal reproduction and impressive dynamics make it a centre speaker that is still well worth considering today—especially for the enthusiast who values a warm, powerful and relaxed presentation.