The compact LSi9s are crammed with high-performance speaker technology.

Since being introduced in 2002, Polk Audio's LSi family of speakers has earned enthusiastic reviews from both audio journalists and consumers. I'd heard the LSi9 bookshelf monitors and LSi15 towers at industry shows and been very impressed by the speakers' relaxed musicality, and their ability to hold their own sonically when compared to much more expensive models. Since I've been using bookshelf monitors for years, when I was asked to do an LSi review, I chose to spend a month with the LSi9s.

At just under 15" tall and tipping the scales at 32 lbs. apiece, the LSi9 is a dense speaker that is also densely packed with clever engineering. It could be described as a "2-and-a-half-way" design — the two matching 5-1/4" mid/woofer drivers operate together below 200 Hz, but one rolls off above that point. Sitting between the two mid/woofers is the 1" Ring Radiator tweeter (made by Vifa), which is also found on other high-end speakers, some costing thousands more than these Polks. The two small ports on the front baffle aren't bass ports. Polk calls them "Acoustic Resonance Control" ports: they're tuned to different frequencies to help reduce sound-muddying cabinet resonances. There is also a bass-enhancing "Power Port" vent on the back side.

You can't see it in the photo above because the right speaker's grille is on, but the LSi9s come as a "mirror-imaged" pair. Notice that the tweeter isn't in a vertical line with the mid/woofers — it's offset a little. With mirror-imaged pairs, one speaker is designated as "right" and the other as "left." Polk's owner's manual recommends that the LSi9s be placed so that the tweeters are toward the speakers' inner edges. I tried them both ways — the recommended approach offered better image focus and more compelling sound overall, while having the tweeters toward the outside provided a slightly wider soundstage. Most of the time, I listened with the recommended placement.

The way I positioned the LSi9s had a big impact on how they sounded. You can watch our speaker placement video to learn about the basics, or get full details in our articles on speaker placement for stereo or home theater setups.

A brief detour

A few years back, I did a lot of research on speaker placement for some of our learning content. One of the most eye-opening things I learned was how speaker placement affects the relationship between bass response and imaging. Generally, if you move a speaker nearer a "room boundary" such as a wall or the floor, you'll increase its bass output. Moving a speaker away from these boundaries reduces bass response but improves spaciousness and imaging. (In the last two houses I've lived in, I've been lucky enough to have a dedicated listening room in the basement, so I could set up my speakers for the best balance between bass response and imaging, without worrying about damaging the décor.)

Armed with this knowledge, the next time I shopped for speakers, I chose a configuration that avoided compromising either bass response or imaging. I bought the speaker system that I still own and enjoy today: a pair of Sapphire III bookshelf monitors and matching Titan powered subwoofer from Audio Concepts (ACI). I placed the Sapphires on stands well out into the room to optimize imaging, and after some experimentation, found a spot for the sub where it provided excellent extension while blending in seamlessly with the sound from the Sapphires.