Polk Audio LSi15,
LSiC, LSi7, and PSW650 Home-Theater Speaker System
I first got wind of the Polk LSi series of
loudspeakers last spring when Polk's Paul DiComo called and asked if I had a few days free
to listen to a prototype loudspeaker. I'm not a professional audio consultant and I don't
normally listen to prototypes, but Paul wasn't interested in my opinion so much as he was
in astonishing me.
And astonish me he did. He delivered Polk's only working
pair of LSi15 loudspeakers -- which turned out to be a handsome pair of
floorstanding 3.5-way loudspeakers with side-firing woofers. These weren't your usual MDF
prototypes with crossovers hanging out the ports (so you can tweak 'em), they were
beautifully finished with cherry veneer and black lacquer side panels. In short, they
looked like one heck of a lot of loudspeaker.
And they sounded fantastic! I expected them to be robust
and dynamic -- and they were. What I was unprepared for, however, was how seamless their
presentation of music was and also how refined they sounded. They didn't sound like a
mass-market loudspeaker in the slightest.
I figured there had to be a catch. There's always a
catch. "How much?" I asked Paul.
He grinned. "$869.95 each!"
That wasn't the catch.
"We have loyal customers," Paul said. "Folks
who have owned Polk loudspeakers for a long time, folks who have never owned anything
else. And lately they've been calling and complaining that they have to buy speakers from
other companies as their tastes develop and they look to buy better and better
loudspeakers. They wanted us to build speakers that sounded better than the ones they
"We've built big, sophisticated loudspeakers before,
but the whole scene has changed. DVD, SACD, upsampled CD -- consumers nowadays have access
to higher-resolution sources than have ever been available before. To hear what these
formats can produce, people need loudspeakers capable of new levels of reproduction
-- and our guys had some ideas about delivering superior sound that was commensurate with
our philosophy of value and support."
Well, he is a company man, of course I'd get the
sales pitch. Even so, if you could buy sound like I was hearing for $1700 per pair, well .
. . there had to be a catch.
"Actually, we've developed a whole line of speakers
based on these concepts," Paul said.
"Well bring 'em on!" I challenged.
"Significant form" is form behind which we
catch a sense of ultimate reality . . .
Paul delivered a 5.1 system based on the LSis: two
LSi15s for the right and left channels; an LSiC for the center channel; a
pair of LSi7s for the surrounds, and a PSW650 subwoofer. It's an impressive system.
All of the speakers share a few key technological elements.
First, there's Polk's "Ring Radiator" tweeter, which is designed with
sophisticated features that keep the sound undistorted and enable it to radiate out from
the speaker to cover a wider area than normal tweeters.
The LSi speakers also utilize a special
Polk-designed 5.25" midrange/woofer that has a heavy-duty superstructure, as well as
double magnets and a special construction technique designed to keep the driver from
"breaking-up" or distorting from undamped internal resonances.
The LSi series speakers also employ Polk's patented
Power Port. This requires a word of explanation. One method of getting low bass sounds out
of a relatively small enclosure is to "tune" the enclosure to a certain
frequency through the use of a port -- essentially a hole cut in the cabinet. Air moves in
and out of the port in response to the motions of the loudspeaker's driver, but, in many
speakers, air turbulence inside the cabinet and at the port's mouth keeps air from passing
through the port easily, thus robbing the speakers of a measurable amount of the bass
efficiency provided by the port. Polk's Power Port is a cone connected to the small port
opening. That creates an increasing cross-sectional column of air that enhances air flow
and the greater ease of motion for the air traveling through the port actually increases
the effectiveness of the port. The result is about a 2dB gain in bass response and a lot
Speaking of ports, the LSi series sports several
small "extra" ports on the speakers' front panels. Polk calls this technique
Acoustic Resonance Control, and what it does is counteract the cabinets' natural internal
resonance. Silencing this resonance allows low-level detail to be more audible, while
preserving the natural sound and clarity of the drivers used.
The LSi speakers are all solidly built from MDF with
internal bracing and separate compartments for the tweeter and midrange drivers. All of
them are magnetically shielded.
Go and catch a falling star . . .
The LSi15 is a 3.5-way floorstanding loudspeaker
with four drivers: a 1" fabric tweeter; two 5.25" midrange drivers, and an
8" woofer. The cabinet is quite narrow, but is also deep. This necessitates that the
woofer be mounted on the cabinet's side rather than its front. Since the radiation pattern
of low notes is 360 degrees, there's no sonic difference between mounting the woofer on
the side of the speaker and the front -- except, that by keeping the cabinet narrow, the
LSi15 combines the imaging capabilities of a small monitor speaker with the
authority and power of a full-range speaker system.
Oh yeah, you may have never heard of a 3.5-way loudspeaker
before. Technically, it's called a Cascade Tapered Array design. That means it
splits the midrange duties between the two 5.25" drivers -- one driver rolls off its
upper frequencies long before the other does, resulting in reduced interaction between the
two at higher frequencies where dispersion is more limited.
The LSiC sells for $579.95, which might seem like a
lot for a center-channel speaker. But stop and think for a minute. Most of the sound and
nearly all of the dialogue is carried in the center-channel speaker. How much
enjoyment would you get from watching most movies if you couldn't hear what the actors
were saying? Some folks would say that the center-channel speaker is the most
important speaker in a 5.1 home-theater system. Count me as one of them.
Early on, most companies treated the center-channel speaker
as a cheap add-on. The result was screechy, shouty dialogue paired with beautifully
reproduced left and right environmental sound effects and movie music. Yeauch-A-Hooey!
The LSiC is one reassuringly solid speaker (7"H
x 21.75" W x 9"D). It places the 1" fabric Ring Radiator tweeter between
two 5.25" midrange/woofers employing a Cascade Tapered Array staggered crossover to
maintain wide dispersion.
The LSi7s cost $404.95 each and employ a single
5.25" driver with the 1" Ring Radiator tweeter. They're handsome two-way
stand-mounted monitors, and, with their bass extension to 53Hz, could be used as
the primary speakers in a small-room music system or as the front and rear channels in a
less ambitious home-theater system.
The $780 PSW 650 is a very serious subwoofer. It's
self-powered, with an internal 165W amp capable of supplying 250W for short-demand peaks.
It can be connected to systems with line-level or speaker-level signals and it even has
its own 80Hz low-pass filters on both inputs -- a nice touch for systems without adequate
bass management. The PSW650 also sports an LFE input that bypasses its own low-pass
filters for when a processor's output is already filtered. (You don't want to
double low-pass filters!)
Most subwoofers make you crouch down behind them if you
want to make adjustments. The PSW650 has a discreetly placed level control on the front
panel. I hate audio gear that makes me kneel before it (or behind it), so I definitely
Inside the robustly built 18.75"H x 17.5"W x
18.75"D enclosure are two 10" drivers (which provide 39% more radiating surface
than a single 12" driver, not to mention almost twice the "motor"
All fell to playing a game of catch as catch can . . .
Paul and I set the system up in my room with the LSiC
on top of my 35" Toshiba, with the LSi15s out a few feet to either side of the
TV. We inserted the PSW650 where my reference Soliloquy S10 subwoofer had previously
lived. The LSi7s were settled on wall-mount stands about three feet above my head
on either side of my comfy couch. I won't say the system was unobtrusive, but it was less
visually dominant than some home-theater speaker systems I've lived with -- and the
cherry/black lacquer finish gave it elegance quite out of place among my furniture. If you
live like a grown-up, however, it won't embarrass your fine furniture by its presence.
That's some catch, that Catch 22 . . .
The first thing Paul and I did, of course, was pull out a
mind-numbingly stupid DVD with great sound effects. Of course I'm talking about Star
Wars Episode One: The Phantom Menace. We pod raced and blew up the Death Star and all
and I was feeling as though I'd been put through the ringer, what with all the spare parts
bouncing off to the left and right and flying directly over my head. Paul was unhappy,
however. "I've heard this system sound so much better," he groused, grabbing my
remote and re-jiggering all my settings. He still wasn't happy when he left, but we
had a pressing engagement with some sushi -- I'd have plenty of time to tinker during the
Turns out I'd been using the LFE output on my processor and
Paul had assumed I was using an unfiltered output. (Remember -- you don't want to double
the low-pass filters.) When I finally set the connections straight, the system roared into
life. And I do mean roared. The PSW650 is flat-out the most impressive subwoofer
I've ever auditioned, whether for home theater or music. It's so powerful in its
reproduction of bottom-end special effects, it could probably stun a terrier at 10 yards,
yet it's capable of producing tight, tuneful music when Paul Chambers walks his acoustic
bass behind a Coltrane solo.
Not that the LSi15s aren't capable of deep, solid
bass. They are. But reinforced by the PSW650, they reproduce a bottom end you could crack
an egg on. I mean solid!
Of course, properly set up, a subwoofer shouldn't make any
sound most of the time -- and the PSW650 doesn't, unless something low needs to be made
audible. In fact, one of the things that impressed me about the LSi system as a
whole was how light and right it sounded.
Shrek, which has beautifully rendered surround
ambience throughout, was filled with delicate bird songs and light little zephyrs and
leaves rustling all around the place. Of course, all of this aural seasoning went a long
way toward making the less, um, plausible aspects of the film seem far more
credible. Since I totally believed in the world Shrek inhabited, I was able to believe in
If one cannot catch the bird of paradise, better to take
the wet hen
Crimson Tide is one of those regrettably rare films
that pairs a demonstration-quality soundtrack with a compelling story, so I was delighted
to return to it with the Polks. There's a scene early on where Gene Hackman, as the
skipper of an attack sub, addresses his massed crew, which is assembled at quayside in a
pouring rainstorm. The sound of the rain is enveloping and Hackman's voice is echoed by
his amplified voice bouncing off the surrounding structures. As the camera shifts angles,
our aural point of view changes. Close-ups of Hackman's face put the sound of the rain in
the back and foreground, while we hear the rain drumming off of -- and dripping down onto
the platform from -- the umbrella held over his head. When the camera shifts to an
establishing shot from the massed sailors, the sound of the rain washes over you.
Forget elaborate setups like Episode One's pod race,
that scene from Crimson Tide is the single most convincing surround-sound demo I've
ever heard, if only because it takes the sounds of everyday reality and convinces us
they're real. I've never been to the planet Tatoonie, but I know what rain sounds
After the speech in the rain, nothing else in the movie,
not even the impressive torpedo explosions and depth charges gave me the same goosebumps
-- although they did move the furniture around a bit.
If pleasure can be had, it is fit to catch it
Set up in my big living room, the Polk LSi
surround-sound speaker system was bigger than life -- but absolutely true to it. I'm sure
I could have built a very impressive home-theater system around four LSi7s, an LSiC,
and a PSW650. But, and especially in my large room, the added solidity and seamless
musicality of the LSi15s made music listening something special. Out of all the
impressive components that make up this system, these floorstanders are something special.
I want to keep them around a while and listen to them more in my stereo system, so look to
onhifi.com for a full review there in
the near future.
If you're looking to provide superlative musical
performance and an impressive home-theater system for your immediate gratification and
long-term pleasure, this one fits the bill. At $4000, this system isn't inexpensive, but
it's less than the price of a lot of high-end stereo pairs. For performance like
the LSi system's, $4000 isn't just a bargain, it's a catch.
Polk LSi15, LSiC, LSi7, and PSW650
Home-Theater Speaker System
Price: $3909.75 USD for complete system (speakers can also be purchased individually)
Warranty: Five years parts and labor (three years on subwoofer amplifier)
5601 Metro Drive
Baltimore, MD 21215