April 2002

Polk Audio LSi9 Loudspeakers

by Doug Schneider

Review Summary Sound Both bass and midrange are "impressively full for such a small speaker -- and smooth"; "has such great bass impact that you forget about all-out extension"; "the upper frequencies" are "every bit as smooth and non-fatiguing as the other areas." Features "One heckuva dense little speaker"; 2 1/2-way design with one woofer providing low bass and the other working into the midrange, where it hands off to a Vifa Ring Radiator tweeter; two sets of binding posts for biwiring, which Polk "recommends you take advantage of." Use Power Port allows close placement of the speakers to walls if necessary; Doug used 26" stands -- "a good height to get the tweeters to ear level." Value "Ear-opening" performance "at just a smidgen over $1000" -- "audio life is very good for admirers of small speakers these days!"

When I pulled Polk’s LSi9 loudspeakers from their boxes, I was reminded of Monty Python’s And Now for Something Completely Different. When I think of Polk, I think big. I don’t know why -- I just do. Perhaps it's due to the giant speakers with all the little drivers on them that I listened to in the ‘80s. But then again, when I look back through Polk’s impressive history, their string of products has shown remarkable diversity.

The $1040 USD LSi9 is positioned "second up" in the LSi series. There is a smaller LSi7 that is similar, but it uses only one woofer. There are also two floorstanders above the LSi9. A matching center-channel and surround speakers round out a full home theater. This is a very interesting proposition because the LSi9s function so well as a stereo pair, and if the others do equally well for home theater, then you have the makings of a high-quality dual-function system.

What Polk has done with both the LSi7 and LSi9 minimonitors is cut way back on the cabinet size and in turn build the smaller box to a higher standard than if it were two or more times larger. You lose bass with a smaller speaker, but you gain in terms of overall refinement. If you want an expansion path for later, you can consider adding a subwoofer.

The LSi9 measures 15"H x 8 5/8"W x 15 1/4"D and weighs in at a hefty 33 pounds. In comparison to many of the other bookshelf speakers in its price range, the LSi9 is a fair bit heavier, and bigger too. However, the bigness is cleverly hidden. The front of the speaker is reasonably narrow, but there’s a lot of depth to the cabinet.

The LSi9 is a 2 1/2-way design. The bottom woofer works up to 200Hz, where it is rolled off with a second-order filter. The top woofer works in the bass region too, and then also continues up through the midrange to 2.4kHz, where it is rolled off with a second-order filter. A third-order filter is used with the tweeter, and that driver then flies off to the stratosphere. The drivers are all of high quality. Polk says that the 5 1/4" woofers are "polypropylene that has been ‘foamed’ with air. This technique serves to suppress cone resonance without adding mass." The tweeter is called a Ring Radiator. Perceptive eyes will notice that it’s actually a Vifa-sourced unit with a Polk Audio faceplate. It’s the same tweeter that’s used in Krell’s ultra-expensive $10,000 LAT-2 as well as other pricey speakers, but it is also used in competitive products like nOrh’s $995 SM 6.9, which I just reviewed.

The LSi9 is one heckuva dense little speaker. It uses 3/4" MDF all around for the main box. Then more panels are added to the sides, top, and bottom. These are decorative, but they also add to the performance by giving the cabinet exceptional strength -- the side walls end up being 1 1/2" thick. The LSi9 and the all-synthetic-marble nOrh SM 6.9 are the most solid speakers I’ve encountered at the $1000 price point. High-quality binding posts flank the back of the LSi9. They allow for biwiring, and Polk recommends you take advantage of it.

Then there’s the Power Port, which looks weird at first. But when you realize its purpose, you have to concede that it’s quite clever. Basically a plate mounted away from the back of the cabinet with a cone pointing into the rear-firing port, the Power Port serves two main purposes. The first is that the cone facilitates air travel through the port, which is said to eliminate port noise and improve efficiency. The second is that it directs the air toward the sides, top, and bottom of the speaker as opposed to straight back. Although Polk would rather you not place the speakers too close to boundaries, redirecting the port's output allows placement of the speaker close to walls if need be. Neat.

On the front are two ARC ports (for Acoustic Resonance Control). These affect the midrange performance and, according to Polk's literature, improve things like vocal clarity (by reportedly removing the chesty quality sometimes heard from speakers) as well as, surprisingly, image stability and depth.

From a what-you-get-out-of-the-box point of view, I’m impressed with what Polk’s come up with in this series of speakers. There’s obviously a lot of research and technology put into the LSi series, and when a company the size of Polk directs its vast resources to designing a speaker this small, you know the company means business. I also like the way the LSi9 looks with its attractive cherry- or ebony-veneer side panels.

Setup

Polk says that the LSi9's sensitivity is 88dB and the impedance is a lowish 4 ohms. Therefore, amplifier matching should be done with some care. I did notice that although my own Blue Circle BC2 75W hybrid mono amps could drive the speakers well enough, they were laboring a bit when doing so -- building up heat and nearly breaking a sweat in the dead of winter. On the other hand, Arcam’s 100Wpc FMJ A32 integrated amplifier proved to be a stellar match. Although the amp is not necessarily a powerhouse into low-impedance loads, it didn’t sweat and powered these speakers nicely. I also used the FMJ CD23T CD player -- a gorgeous and clean-sounding digital source. Wiring was all Nirvana S-L series.

I placed the speakers atop 26" Osiris stands -- a good height to get the tweeters to ear level -- and I listened to the speakers exclusively without grilles.

Sound

The first of the LSi9's sonic attributes that struck me were its midrange and bass. Both were full -- impressively full for such a small speaker -- and smooth. The speaker has a unique sound that really captivates and, as a result, requires little "brain break-in" to accustom you to a small speaker, even if you're used to listening to floorstanders.

Polk says the LSi9 has a -3dB low-frequency point of 50Hz -- realistic with some careful setup. Nevertheless, what this figure doesn’t tell you is how much impact these speakers have down low. The LSi9 is capable of wallop on the bottom end that is very impressive.

The first track on Ani DiFranco’s Not a Pretty Girl [Righteous Babe Records RBR007], "Worthy," opens up with some deep, rich bass tones. These can get stunted with some small speakers, making the tones sound, well, small. It’s not that the LSi9 goes really deep -- it’s just that it has such great bass impact that it makes you forget about all-out extension. The drums on the first track of the Mulholland Drive soundtrack [Milan 35971] jump to life with uncanny warmth and presence.

The midrange has oomph that is very impressive too. Vocals rocket out of this speaker, but without being too forward. There is fullness along with wonderful smoothness; as I wrote down: "a hint of lushness about them." They're tubey-smooth, in fact. And, yes, chestiness is remarkably absent. That’s the woolly, overly resonant character that occurs often with male vocals. Whether it’s due directly to those ARC ports or a combination of other things, it’s just not there, and what’s left is a clear and full view of the singer’s voice.

Jazz pianist Norah Jones’ smooth vocals on her debut CD, Come Away With Me [Blue Note 32088], have a reach-out-and-touch-them fullness that I don’t hear with many speakers. The voice hovers in space with clarity and robust presence. The LSi9s seem to impart a wee bit of their own excitement into the presentation, and I have to admit that I like it. The LSi9s also nail the lively and visceral sounds on the Buena Vista Social Club Presents: Omara Portuondo [World Circuit/Nonesuch 796903]. Percussion, guitars, horns, and, of course, Portuondo’s voice sparkle in a way that’s rare not just among the best small speakers, but big speakers too.

The center image is amazingly solid, and voices have absolutely realistic size, as they should but often don't. The width and depth of stage that these speakers create are outstanding too. I actually ended up spreading the speakers out more than usual and still achieved a rock-solid center image. When I cued up the soundtrack from The Mission [Virgin 90567-2], I got an expansive choral presentation with imaging that rivaled the amazing Amphion argon2 -- no small feat. When the full weight of the orchestra kicks in, the low end is limited, but the LSi9s still delivers admirable sound pressure levels, create a room-filling sound, and certainly don’t crap out even at high volume levels.

The LSi9 is a little speaker that can. It’s small but heavy, a little shy of bass depth, but it still packs a punch. It lacks real weight on instruments like piano and drums, but it makes up for this with excellent definition (within its range), smoothness, control, and, of course, that impact. When the keys get struck or each drum gets hit, the speakers don't hold back, and this is especially impressive. A subwoofer will provide extra weight down low, but don’t think you necessarily need it to enjoy the LSi9s. They may be little guys, but aspects of their performance make them sound big.

Where the Polk folks have also done good things with the LSi9 is in the upper frequencies. I wouldn’t call this area punchy and full like I do the bass and midrange, but it is every bit as smooth and non-fatiguing as the other areas. Coherency from top to bottom is very good. I had this speaker and nOrh’s SM 6.9 in my room during the same period. The nOrh speaker sounds good, but I noticed some raggedness in the tweeter’s range. Despite the fact that the driver is the same for the SM 6.9 and LSi9, the Polk speaker sounds more refined in the treble. It’s smooth, clear, extended, and without a hint of grain or edge.

Comparison

This LSi9 is a high-class bookshelf speaker worthy of comparison to the best of the bookshelf set. These days, one of my favorites is Amphion’s argon2 priced at $1265 per pair.

Physically the LSi9 is larger by having significantly more cabinet depth. It’s also heavier. Both look good and are finished to a high degree -- far above the vinyl "veneer" on MDF that we see in the lower-price bracket. In terms of appearance, the two speakers are very different, and the LSi9, with its double woofers and front ports, is a lot more techie-looking if you don’t put the grilles on. The argon2 has a more understated but elegant appearance.

In terms of performance, both speakers are exceptionally refined, and when set up carefully in a room, they have bass extension and room-filling sound that is roughly the same. However, how they go about delivering that bass differs substantially.

The LSi9 is more visceral -- that punchiness I keep mentioning. The argon2 has good impact, but is a little fuller and warmer. The argon2 seems to roll off its bass output more slowly, while the LSi9 deliver a POW and then shelves off quite quickly. Subjectively, this makes the argon2 weightier and more robust-sounding, while the LSi9 comes across as more lively and visceral.

On the opposite end of the spectrum, the high frequencies are similarly refined and exemplify just how good these small speakers can sound and why they compare so favorably to more expensive offerings. Same goes for the imaging, where they both not only compete well against many more expensive speakers, they better many of them too!

However, in the midrange, things change quite substantially again. The LSi9 projects things forward a little more and gives a more bulbous presentation. The argon2 sounds a little more neutral, and in comparison, a little more laid-back. Both speakers are capable of dissecting a recording, but in different ways. The argon2 lays out the presentation like a collage before your eyes. The LSi9 likes to push a few of the details out at you more.

The other main difference is in the transparency through the midrange. The argon2 allows me to hear into the recording a little more -- it's a little more transparent, a little more see-through. This can be heard on some recordings that have complex percussion or string instruments, and also something as simple as spoken words. There’s a wee bit more texture and detail there. The LSi9’s midrange is wonderfully smooth -- liquid, in fact -- and detail is certainly a strong suit, but the LSi9 doesn’t quite resolve as much. Keep in mind, though, that what’s delivered here will still rival the sound of speakers that cost much more than the LSi9.

Conclusion

The And Now for Something Completely Different attitude has worked well for Polk Audio. They’ve hit the bull's-eye with the LSi9. Not only is it an exceedingly refined, first-class performer, it has specific sonic qualities that make it stand out in its price class. I really liked the combination of having a punchy and lively presentation, but also having the refinement and smoothness that I expect in a top-notch speaker. This speaker jumps to life like a Spring Break party, but retains the sophistication of a black-tie dinner. This combination is something you rarely find in small speakers at any price. The LSi9 also images with precision and provides a level of robustness that is thoroughly captivating.

All this adds up to a level of performance that is ear-opening -- and at just a smidgen over $1000. I’m sure even big-speaker lovers are going to find a lot to like in this little gem. Audio life is very good for admirers of small speakers these days!

...Doug Schneider
das@soundstage.com

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