The Ultimate Floorstanding Loudspeaker

  • Separate chambers for the midrange and tweeter improve transient response and imaging
  • Cassini oval subwoofer drivers have more surface area for superior low-frequency response
  • Klippel motor optimization ensures smooth volume spectrum ends for uniform performance at all volumes
  • Patented Dynamic Balance® technology eliminates resonance so you hear good sound instead of distortion
  • $1,999.95
  • $999.98 EACH
  • Free ground shipping on all orders

The Flagship of

Floor-Standing Speakers

Sound That Blankets the Soul

The exclusive Polk Audio Dynamic Sonic Engine allows the LSiM707 to engulf listeners. The unique alignment of internal components allows this speaker within the speaker to disperse sound over a wide area.

  • Tech Specs
  • Reviews
  • Q & A
  • Support
Tech Specs


  • Total Pieces


  • Total Frequency Response
    20 Hz → 40,000 Hz
  • Nominal Impedance
    8 ohms
  • Sensitivity (1 watt @ 1 meter)
    88 dB
  • Lower and Upper -3dB Limits
    38 Hz → 30,000 Hz


  • Cabinet Warranty
    5 years
  • Drivers Warranty
    5 years
  • Original Purchaser Only


  • Qty Included
  • Height
    50.81" (129.06 cm)
  • Width
    9.5" (24.13 cm)
  • Depth
    18.44" (46.84 cm)
  • Weight
    99.2 lbs (45 kg)
  • Mid-High Array Driver Enclosure Type
  • Mid-High Array Driver Complement
    • (1)  1" (2.54 cm) d (Round) Enhanced Ring Radiator - Tweeter
    • (1)  3.25" (8.26 cm) d (Round) Super Cell Aerated Polypropylene - Midrange
    • (1)  6.5" (16.51 cm) d (Round) Super Cell Aerated Polypropylene - Mid/Woofer
    • (2)  6"" (15.24 cm) h x 9" (22.86 cm) w (Oval) Cassini oval, Super Cell Aerated Polypropylene - Subwoofer
  • Enclosure Type
    Mid-High Array Enclosure Type: Sealed
  • Enclosure Type
    Subwoofer Enclosure Type: Dual PowerPort bass venting


  • Type
    Orth Crossover Design
  • Midrange/Woofer Crossover Frequency
    100 Hz
  • Tweeter/Midrange Crossover Frequency
    3000 Hz


  • Recommended Amplifier Power Per Channel
    20 watts → 300 watts


  • Audio Inputs
  • Speaker Inputs
    (2) Pair of Binding Posts - Gold Plated
Q & A

Dynamic Sonic Engine

Exclusive Polk Audio Dynamic Sonic Engine design optimizes the midrange driver and the ring radiator tweeter in separate interior chambers for improved transient response, superior imaging and greater horizontal off-axis response.

Beautifully Blended Bass

Cassini oval subwoofer drivers have more surface area than round drivers, dramatically improving their low-frequency response for deep, well-blended bass. The result is sound that seamlessly varies among frequencies for more lifelike reproduction.

Voice Coil Innovation for Enhanced Response

Innovative overhung voice coil design augments the excursion length for subwoofer drivers, increasing their power-handling capabilities and enhancing bass response. Extended linear motion allows lots of movement in a limited space, eliminating impedance and extending mid- and high-frequency response.

Klippel Motor Optimization

Laser measurement technology ensures a smooth excursion path at either end of the volume spectrum for uniform performance at high and low volumes.

Dynamic Balance® Technology

Polk Audio engineers created a way to design out distortion-causing driver and system resonance. That means you hear the sounds created by the artists not the components.

Super Cell Aerated Polypropylene Cone

Aerated Polypropylene has the ideal balance of superior damping properties and lightweight stiffness for more efficient action with less distortion. The durable, computer-modeled, injection-molded butyl rubber surrounds suppress unwanted cone resonances for purer sounds note after note.

Extra Solid Cabinet Enclosures

High-quality, heavy-duty enclosure construction on the back and bottom, as well as baffles with substantial internal bracing and separate interior cabinetry for each driver eliminate cabinet resonances.

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