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 bookshelf loudspeaker employs a 3-way driver system for crisp, detailed highs;
natural, lifelike midrange; and accurate, dynamic midbass. The bookshelf
loudspeaker houses a 1" (diameter) Dynamic Balance Enhanced Ring Radiator
Tweeter, a 3.25" (diameter) Dynamic Balance Super Cell Aerated Polypropylene
cone midrange driver, & a 6.5" (diameter) Dynamic Balance Super Cell Aerated Polypropylene
cone midbass woofer.
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
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
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 impedance.
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
Orth Crossovers: The Polk Audio LSiM series bookshelf
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 response.
- Tweeter/Midrange Crossover:
2.8 kHz 18 dB/oct
- Midrange/Midbass Crossover:
300 Hz 12 dB/oct
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 perfect timbre-matching.
Frequency Response Note: The overall frequency response is
36Hz 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 veneer.
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,
Dynamic Sonic Engine (DSE): At the heart of the Polk Audio
LSiM series bookshelf loudspeaker 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 midbass woofer.
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 bookshelf 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 voicing balance.
Color-Coded: The bookshelf speaker's binding posts are
color-coded (red/black) for easy identification between positive & negative.
Placement: The LSiM series bookshelf loudspeaker is designed to
provide excellent performance on a bookshelf or placed on a floor stand. For
best results place LSiM bookshelf loudspeaker so the tweeter height is within 6"
of your seated ear height.
Positioning: The LSiM series bookshelf loudspeaker can be used as a
front speaker or rear-channel surround speaker.
- Front Application: To enjoy the most
realistic stereo image and lifelike sound, place the speakers so that an
equilateral triangle is created between the speakers & your favorite
listening position. Angle the speakers toward the middle as necessary in
order to support a more solid center image. Experiment with the distance
between your speakers & both the back/side walls. You'll experience some
bass boost with the speakers located closer to walls.
- Rear Application: If you are using your LSiM series bookshelf
loudspeaker as a rear channel in a home theater system, it should be
placed on the rear or side wall, slightly above (and, on the side wall
behind) the listening position. Angle it toward the listening area if
Rubber Feet: The bookshelf speaker comes with 4
self-adhesive rubber feet so it will sit securely on your stand or shelf.
Note: The speaker does not offer any wall-mount options.