Performance Objectives of the Polk Audio LSiM Series Loudspeakers: The
LSiM series loudspeaker is Polk Audio's best high-performance loudspeaker. Polk
Audio designed the LSiM series loudspeakers to create a sound that virtually
transports you to the scene of the recorded performance. It was engineered &
created with the following performance objectives in mind.
- Pleasing tonality, even during extended listening at
- Crisp, lifelike impulses, transients & coherent detail
without any unnatural ringing or decay.
- Natural reproduction of complex low frequency instruments &
- Uniform sonic representation within the listening area &
immersive spatial impression.
- Reproduce concert/theater levels while maintaining linearity
- Compatibility with a wide array of electronics both past,
present & future.
- Work as promised for many years of enjoyment (5 year parts & labor
Dynamic Balance: Dynamic Balance is a proprietary Polk Audio
technology using laser imaging to determine what combination of speaker
materials create the least amount of resonance. Eliminating resonance in
speakers results in a wide, smooth response, & low distortion.
3-Way Driver System: The Polk Audio LSiM series center channel loudspeaker employs a 3-way driver system
for crisp, detailed highs; natural, lifelike midrange; and accurate, dynamic
midbass. The center channel houses a 1" (diameter) Dynamic Balance
Enhanced Ring Radiator Tweeter, a 3.25" (diameter) Dynamic Balance Super Cell
Aerated Polypropylene cone midrange driver, & two 6.5" (diameter) Dynamic
Balance Super Cell Aerated Polypropylene cone midbass woofers.
Enhanced Ring Radiator Tweeter: The ring radiator tweeter was a vital
element in the success of Polk Audio's original LSi Series. Polk Audio engineers
have made some nuanced improvements in the design of this tweeter. First, they
reshaped the tweeter's bullet-shaped phase plug, allowing it to move farther out
of the baffle, improving dispersion and eliminating horn-loading. Next, they
opened up the tweeter's face-plate, then redesigned the tweeter's diaphragm roll
to make it more efficient and improve dispersion even more. Finally, they gave
the new ring radiator tweeter its own tuned enclosure (Dynamic Sonic Engine).
This new ring radiator tweeter boasts higher power handling, extended dynamic
range, improved dispersion and extended top-end response.
Super Cell Aerated Polypropylene (APP) Cone Woofer: If the perfect
cone material is lightweight (for faster, more efficient action) and stiff (for
less distortion-causing flex), with enough internal damping to suppress and
offset any limitations of its lightweight stiffness, then the Super Cell APP
Cone Material is about as perfect as cone material gets. Aerated Polypropylene
(APP) is a mineral-filled polypropylene material that's been "puffed up" with
injected air to form a honey-comb structure. Polk Audio's original APP cone
approached the ideal balance of lightweight stiffness with high damping, along
with good resistance to moisture, UV and temperature extremes. Next generation
LSiM series loudspeakers employ Polk Audio's next generation of APP Super Cell.
In Super Cell APP, the "puffed cells" are larger, for a thicker cone material
that actually has less mass than the original APP material. Super Cell APP has
larger cells, for lighter weight and more inherent damping, plus uncompromised
stiffness, for unsurpassed transient response and resonance suppression.
Butyl Rubber Surrounds: Durable, soft, injection-molded butyl rubber
surrounds are tuned to absorb and suppress unwanted cone resonances. Polk
Audio's butyl rubber material is impervious to UV, extreme temps & humidity, for
a lifetime of smooth, reliable sound.
Extended Linear Motion Voice Coils: Allowing lots of movement in a
limited space, ELM Voice Coils power the LSiM series speaker's mid-range &
mid-woofer drivers to extend their higher-frequency response with much less
Cast Aluminum Baskets: These lightweight, cast aluminum baskets
provide a rigid structure for precise alignment of the speaker's active parts,
for flat response & low distortion, with no mechanical resonances or ringing.
The open design provides ample venting for unobstructed linear movement.
Orth Crossovers: The Polk Audio LSiM series center channel speaker
employs proprietary engineering, designed and patented by Polk Audio to maintain
a lower order crossover design & increase power handling. Orth Crossovers
feature Mylar/polypropylene capacitors for sparkling highs & Air Core Inductors
for superior transparency. Notch Filters and sophisticated Zobel circuits smooth
the impedance curve of the system for more efficiency & better high frequency
- Tweeter/Midrange Crossover: 2.8 kHz, 18 dB/oct
- Midrange/Midbass Crossover: 280 Hz, 12 dB/oct
(midrange), 6 dB/oct (midbass)
Timbre-Match Series: You can achieve incredible realism & seamless
surround effects when you build a complete Polk Audio LSiM series speaker
system. All LSiM series speaker models feature the same components & tuning for
Frequency Response Note: The overall frequency response is
30Hz to 40kHz & the -3dB frequency response is 50Hz to 30kHz.
Real Wood Veneer: The Polk
Audio LSiM loudspeaker is finished in a real, natural, furniture-grade wood
MDF Enclosure: The enclosure is an integral part of the sound design
of the Polk Audio LSiM series loudspeaker. All LSiM cabinets are made of .75"
MDF, with wide-radius baffles of robust 1.25" MDF. Substantial internal bracing
(each driver has its own separate non-parallel chamber) increases efficiency and
banishes internal resonances & standing waves, for high power handling and
incredible smoothness. Wide-radius baffles, along with zero-diffraction magnetic
grilles, help stabilize imaging for a very wide, well-defined soundstage.
Dynamic Sonic Engine (DSE): At the heart of the Polk Audio LSiM series
center channel speaker is an enclosure-within-the-enclosure design (known as the
Dynamic Sonic Engine) that houses the mid-range driver & the ring radiator
tweeter. Molded into one rigid piece, the DSE enclosure tapers to a "turbine"
that reduces back-wave reflections. The DSE combines its two speakers in an
aligned, optimized array for wide, uniform dispersion in the critical 200Hz-2kHz
midrange, improving transient response. The combination delivers exact
timbre-matching, improved high-frequency dispersion and greater horizontal
Note: The ring radiator tweeter & midrange driver are
housed in a separate internal sealed enclosure from the ported enclosure
which houses the two midbass woofers.
PowerPort Bass Venting: PowerPort Bass Venting is a Patented Polk
Audio technology that uses a specially designed "cone" at the mouth of the bass
port to direct moving air as it exits the port. Air moving out of a bass port
creates turbulence, which can result in boomy distortion & "port noise",
especially at high volume. This distortion can cause bass output losses up to
3dB, wasting lots of amp power. To eliminate bass-stealing turbulence at the
mouth of the port, Polk Audio engineers designed the PowerPort. It's unique
shape promotes "laminar" airflow even in short tube ports by mimicking the
properties of longer, flared port openings. No turbulence means no wasted power,
which means more efficient bass response.
Zero-Diffraction Magnetic Grille: The super thin (1mm),
zero-diffraction grille has no measurable effect on the speaker's response.
Completely unobtrusive, stylishly sheer; the grille locks into place
Dual Gold-Plated Binding Posts: The center channel loudspeaker
has two sets of gold-plated binding posts connected by wire-jumpers. The gold-plated binding posts will accept bare wire
(16-12 AWG), pin
connectors, spade connectors, & banana plugs (single only).
Bi-Wiring/Bi-Amping: Using the dual posts, you can bi-wire or bi-amp
the speaker. Bi-wiring or bi-amping the speaker provides improved bass & treble
performance. If you decide to bi-wire or bi-amp, you must remove the jumpers between the terminal posts (failure to do this could result
in damage to your amplifier and loudspeakers).
- Bi-Wiring: Bi-wiring can provide
noticeable improvements in the overall transparency of your loudspeakers.
Run separate speaker wires to the low & high frequency drivers from a single
amplifier (the upper set of binding posts are for the high frequency
drivers; the lower set of binding posts are for the low frequency drivers).
- Bi-Amping: Bi-amping allows you to use
separate amplifiers for the high & low frequency sections of your
loudspeaker for greater dynamic range & lower distortion. We recommend that
your separate amplifiers have identical gain to preserve the speaker's
Color-Coded: The center channel speaker's binding posts are
color-coded (red/black) for easy identification between positive & negative.
Placement: With today's modern flat-panel TVs, the most
popular placement, and our recommendation for your center channel speaker, is
beneath your TV screen. You may also place the center channel speaker above your
TV, should you choose. The LSiM center channel loudspeaker is very heavy (42.3
lbs) and we do not recommend wall mounting it, unless placed on a sturdy shelf.
Note: The LSiM center channel speaker is not
Rubber Feet: The center-channel speaker comes with 4
self-adhesive rubber feet so it will sit securely on your stand or shelf.