Polk LSiM 707 2016 Cherry Finish

For sale: Polk LSiM 707 speakers (pair), in excellent condition inside and out with no issues. Consecutive serial numbers, original owner.  Purchased in December 2016, light use at low to moderate volumes (estimated 100 hours min, 200 hours max).

Price: $1,400

Technical Summary:

• 20Hz to 40kHz, overall response
• 38Hz to 30kHz, -3dB response
  
• handles 20-300 watts
• sensitivity 88 dB
• 8-ohm impedance
• 1" ring radiator tweeter
• 3-1/4" super cell aerated polypropylene midrange
• 6-1/2" super cell aerated polypropylene midbass
• dual 6" x 9" Cassini oval, super cell aerated polypropylene woofers
• DSE dual enclosures for tweeter, midrange & midbass
• dual PowerPort® technology (for the woofers only) improves bass response
• Orth Crossover Design
• Midrange/Woofer Crossover  Frequency 100 Hz
• Tweeter/Midrange Crossover Frequency 3000 Hz
• dual 5-way gold-plated binding posts allow bi-wiring or bi-amping
• hand-rubbed lacquer finished real wood veneer
• 9-1/2"W x 50-13/16"H x 18-7/16"D
• base measures 10-1/2"W x 20"D
• weight: 99.2 lbs per speaker

This is a marvelous sounding pair of audiophile-grade speakers, especially at this price point. If you are not familiar with them, just Google " 707 reviews" and you will find more than enough information to satisfy your curiosity. The following reviews are representative: 

 

 

Additional technical details are provided below, but the best way to judge is to come have a listen. Unfortunately, due to bad experiences with shipping, I will only sell to local purchasers (Pasadena CA area).

Technical Description of LSiM 707s:

Dynamic Sonic Engine (DSE): At the heart of the Polk Audio LSiM series floor-standing 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 off-axis response.

Note: The ring radiator tweeter, midrange driver, & midbass woofer are housed in a separate internal sealed enclosure from the ported enclosure which houses the two oval subwoofer drivers.

Dynamic Balance: 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.

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.

Cassini Oval Subwoofer Drivers: The Polk Audio LSiM series floor-standing loudspeaker uses dual Cassini oval subwoofer drivers. The Oval woofer shape increases surface area for deeper, more musical low-frequency response, while allowing for a narrower baffle design. The overhung voice coil design allows larger excursions & higher power handling. As a result, the bass response is deep & blending is smooth.

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 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.

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 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.

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.

Enhanced 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. The LSiM subwoofer drivers use Overhung Voice Coils, which allow the larger excursions and greater power handling necessary for big subwoofer performance.

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 floor-standing 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.

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.

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 magnetically.

Dual Gold-Plated Binding Posts: The floor-standing 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).

 Rubber Feet & Adjustable Floor Spikes: Rubber feet & adjustable floor spikes are included with the LSiM floor-standing loudspeakers to anchor & stabilize the speaker on any type of floor (carpet, tile, or hardwood).