|Polk Audio LSi Series Speaker System|
|Home Theater Loudspeakers Speaker Systems|
|Written by Matthew Evert|
|Thursday, 01 April 2004|
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Polk Audio is a trusted name in home and car loudspeakers, offering high quality transducers at very fair prices for decades. Founded in 1972 by two audiophiles, Matthew Polk and George Klopfer, Polk Audio has grown to become one of the world’s most successful brands of high-quality home loudspeakers. Polk Audio prides itself in having employees that truly love music and care about good sound rather than people that just “sell boxes.” The LSi Series loudspeakers are Polk’s most recommended line of speakers for “serious listeners.” The LSi home theater speaker system evaluated here includes the LSi15s at $1,740 per pair, used as the main loudspeakers, a LSiC center channel speaker at $580, and a pair of LSiFX surround speakers costing $1,060 per pair.
The LSi15s are tall and sleek works of art. They stand eight-and-five-eighths inches wide by 45.5 inches high by 13 inches deep. Tipping the scales at 66 pounds each, these are not lightweight speakers by any means. The cabinet consists of a high gloss black laminated main cabinet made of three-quarter-inch medium density fiberboard (MDF) with double thickness side panels covering the bottom two thirds of the main cabinet. The side panels, available in cherry or ebony, serve as extra dampening to further deaden the cabinet. Careful thought was put into the design of the cabinet to isolate the mid/high-frequency drivers from the eight-inch side-firing woofer in the lower half of the cabinet. The LSi15 is mounted on its own stand to make room for a uniquely designed floor port for the woofer. This port features a cone, as Polk’s marketing team explains, that promotes an orderly flow of air exiting from the enclosure without creating any additional noise due to turbulence and increasing speaker efficiency.
The LSi15s sport a one-inch Ring Radiator tweeter, two five-and-a quarter-inch aerated Polypropylene drivers and an eight-inch woofer. Polk calls this a “3.5-way” design speaker that includes an unpowered woofer. All five speakers feature the same aforementioned tweeter and drivers. The tweeter is quite an impressive component, with the same technology used in Krell’s $35,000 Revolution speakers. The low-mass woven diaphragm is supported at two pivot points with the voice coil located in the middle of the points. This allows for less unsupported regions of the diaphragm and thus less audible resonance from the tweeter. The drivers are made of air “foamed” polypropylene that yields a cone that is 15-20 percent lighter than traditional polypropylene cones. These lighter cones result in less driver resonance. Each speaker also features dual gold-plated five-way binding post inputs for robust wiring configurations. These posts allow each speaker to be bi-wired or bi-amped.
Polk speakers were designed to last. Each speaker is subject to rigorous environmental testing to make sure that ultraviolet (UV) light does not degrade the speakers’ rubber and plastic parts for well over 20 years. Heat and humidity tests are also done to make sure these speakers hold together for a lifetime.
For movie dialogue reproduction, one needs a good center channel. Polk delivers with the LSiC. This matching black high-gloss cabinet features a ring radiator tweeter and two five-and-quarter-inch midrange drivers. This rectangular cabinet stands seven-inches tall, 21.75 inches wide, nine inches deep and fit nicely on top of my 32-inch Toshiba CRT.
The LSiFX surround speakers are the perfect match to the LSiC and LSi15 speakers, with a matching black gloss finish and black grille. The set of all five speakers shine like Darth Vader’s polished helmet and wield the Force, as does Mr. Vader. By the Force, I mean plenty of musical power and detail, not supernatural powers. That said, at 24 pounds each, they could be a little heavy for one person to mount on a wall, so I suggest you take your time in setting them up and recruit a friend if possible (ideally Yoda, if he is available). The FXs are much larger than my old Energy Take 2 speakers at 15 inches tall, 13.75 inches wide, and 10 inches deep. The FXs are more versatile, featuring a switch to adjust from dipole to bipole mode and having the bi-ampable binding posts. The bipole/dipole switch is located under the right grille on each speaker and is handy if you are limited in where you can mount the speakers. I have a window towards the middle back of my listening room, so I opted to use the bipole mode and mount the speakers slightly behind my couch. If you prefer to mount the speakers directly next to the listening position, it is recommended to use the dipole mode instead. I found this to be a very nice feature. Again, the FXs used the same mounts for the wall. Although awkward to hang on the wall, the mounts also are functional in that they feature the “nipples” on the power ports for reduction of noise stemming from high velocity air exiting the speaker. As with the LSi15s, the power ports route bass energy directly to the wall mounts and thus generate some needed thump towards the back of the room.
The LSi Series speakers are well-constructed and are well matched with each other. The LSi15s were placed about seven feet apart and about 32 inches from the front wall. I also tried to pull them away from the sidewalls by about 22 inches to let them breathe and improve imaging. The floor-mounting stand for the LSi15s make a good lift point for moving the speakers around. Just be sure to lift them from the back of the speaker, since the front grille is fragile and spans the entire length of the speaker. After targeting the LSi15s’ drivers at a point about a foot behind my head in my listening position, I was quickly up and running with richly detailed stereo sound. The speakers were broken in for me by Polk, yet I ran music through them for an additional 50 hours prior to evaluation to be sure they were ready to go. I listened to the LSi15s for a while with my Parasound preamp and amplifier and later through the Harmon Kardon AVR630, a receiver that I’m reviewing in an upcoming issue.
After the mains were set up and dialed in, I quickly got the center mounted on top of my TV and bi-wired into my receiver. When using a receiver, be sure to select the “large” setting for the front LSi15 speakers. I made this mistake once and the woofers had no “woof” to them. You can use the “small” setting for the LSiFXs and the LSiC. I tried listening to some movies with and without my Energy ES10 subwoofer, and preferred the bass reproduction of the ES10 to the woofers built into the LSi15s. I found the system sounded best with the ES10 turned on and the receiver passing everything below 80Hz to it. If you do not have a subwoofer, then obviously you will be pleased to have the LSi-15s’ woofer there to help out in the bass department. The LSiFX speakers are versatile and once I figured out where the only feasible place was to mount them (I have windows and doors that tend to complicate my room set-up), they were very flexible with the dipole/bipole switch. Polk provided some handy mounting templates so that you can get the correct distance between the two mount screws marked on your wall. Mounting them was a bear, but with the help of a friend, they mounted up after some tweaking of the mounting screws and locating some material to place under the mounts to take care of annoying rattle when played at volume.