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Polk Audio LSi M 705

Floor-standing speaker (Mount Vernon Cherry)

9 Reviews | 1 question - 1 answer

Item # 107LSI705C

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Our take on the Polk Audio LSi M 705

Have you ever listened to your favorite song on the radio, and then heard it live and realized how much more detail and impact it carried? That's the feeling you'll get when you start listening to your music and movie soundtracks played through Polk's LSi M 705 floor-standing speaker. You'll hear a wide, deep soundstage with realistic imaging fleshed out in pinpoint detail, and anchored by effortlessly deep bass.

High-quality sound that envelops and excites you

Have you ever listened to your favorite song on the radio, and then heard it live and realized how much more detail and impact it carried? That's the feeling you'll get when you start listening to your music and movie soundtracks played through Polk's LSi M 705 floor-standing speaker. You'll hear a wide, deep soundstage with realistic imaging fleshed out in pinpoint detail, and anchored by effortlessly deep bass.

It'll faithfully reproduce your most demanding audio sources from top to bottom, without any help from a separate subwoofer. Use a pair of LSi M 705s to create a high-end stereo music setup or as front speakers in a knock-out home theater system. Building upon the widely acclaimed LSi family of speakers, the new LSi M series incorporates the latest developments in speaker technology, fitted into a newly designed enclosure that's beautifully sculpted and luxuriously finished.

Rich, lifelike details with crisp mids and highs

Polk Audio LSi M 705 Floor-standing speaker

Add incredible sound — and great looks — to your home's entertainment system.

The heart of the LSi M 705 is Polk's Dynamic Sonic Engine. Made up of a 3-1/4" midrange driver and a 1" ring radiator tweeter in its own acoustically sealed enclosure, this tightly spaced duo acts like a "mini-monitor."

The precise alignment of the midrange and tweeter allows them to disperse sound over a wide, uniform area with excellent off-axis response in the critical 200 Hz to 2,000 Hz midrange.

Enjoy accurate dialougue for TV and movies

The ring radiator tweeter features several improvements from the version in the earlier LSi line. A slight reshaping of the tweeter's bullet-shaped phase plug allows it to move even farther out of the baffle, while a redesigned diaphragm has made the tweeter even more efficient.

It even has its own tuned enclosure within the Dynamic Sonic Engine. These changes result in higher power handling, extended dynamic range, improved dispersion, and extended high-frequency response — all the way up to 30,000 Hz!


Advanced driver material for even more realistic sound

The original LSi speakers featured a light, stiff mineral-filled polypropylene cone that was "puffed up" with injected air to form a honeycomb-like structure. The new super cell aerated polypropylene uses larger "puffed cells" to create a cone material that's thicker yet lighter than the original. It's used in both the midrange and midbass drivers, as well as both woofers, allowing them to move faster and with more efficiency.

Dual woofers deliver smooth, effortless bass

Low on the '705's front baffle you'll notice dual 5" x 7" woofers. The oval shape helps them produce tight low-frequency music and movie sounds while maintaining a narrow cabinet width. Plus, each woofer has its own PowerPort® — a unique Polk design that positions specially designed "cones" at the mouth of the bass ports to direct moving air to eliminate bass-stealing turbulence. No turbulence means no wasted power, which means more efficient bass response.

Four-way design for clear, low-distortion sound

The LSi M 705 features a 4-way design, meaning that the tweeter handles only the highest of frequencies, the midrange handles the middle frequencies, the midbass handles the mid to low frequencies, and the woofers handle only the lowest frequencies. This separation allows each driver to perform within its optimum range, meaning you'll hear sound with absolute clarity and stunning impact. And this speaker uses proprietary Orth Crossovers, making it extremely efficient and easier for your receiver or amplifier to drive.

Careful cabinet design with a stunning real wood veneer

The '705 cabinet is made of heavily braced 3/4" thick MDF with an even thicker front baffle (1-1/4") to keep distortion to a minimum. Each driver has its own separate, non-parallel chamber to increase the efficiency of each driver and eliminate internal resonances and standing waves. Dual gold-plated binding posts let you bi-amp or bi-wire this speaker for even better performance.

The magnetic grille easily snaps on and off, and it measures less than 1mm thick, so it won't interfere with the sound. And finally, the curved cabinet is finished with a furniture-grade, real-wood veneer that's hand-polished to achieve a gorgeous glow in your home.

Complete your home theater system

Achieve startling realism and seamless surround effects when you build a complete LSi M system. All LSi M models feature the same components and tuning, so you can create any combination of towers in the front of your room with a center channel speaker for crisp dialogue, and either bookshelf speakers or dedicated surround speakers in the back of your room for wraparound sound effects.

Product Highlights:

  • frequency response 42-30,000 Hz (-3dB)
  • handles 20-250 watts
  • sensitivity 88 dB
  • 8-ohm impedance
  • 1" ring radiator tweeter
  • 3-1/4" super cell aerated polypropylene midrange
  • 5-1/4" super cell aerated polypropylene midbass
  • dual 5" x 7" super cell aerated polypropylene woofers
  • dual PowerPort® technology (for the woofers only) improves bass response
  • dual 5-way gold-plated binding posts allow bi-wiring or bi-amping
  • hand-rubbed lacquer finished real wood veneer
  • 8-5/16"W x 47"H x 14-3/8"D
  • base measures 9-1/4"W x 15-3/4"D
  • weight: 78 lbs.
  • warranty: 5 years
  • Our 60-day money-back guarantee
  • sold individually

What's in the Box:

  • Floorstanding loudspeaker (cherry)
  • Magnetic grille (black)
  • 4 Spiked feet (installed)
  • 4 Rubber feet (installed)
  • 5mm Allen wrench
  • Owner's Manual CD-ROM
  • Quick Start Guide
  • "Read First" note
  • Thank You letter

By Far, the best looking Tower speaker I've ever seen! Looks like it belongs in the 25th Century.



Polk Audio LSi M 705 Reviews

Average Customer Review(s):

(9 Reviews)

Polk Audio LSi M 705

Crutchfield customer from Columbia, MD on 11/19/2017

Crutchfield Customer Review (What's this?)

I was very impressed with the sound of the Polk 705s. I replaced a set of Magnapans which I had coveted for 30 years. The Polks are much more focused, bright and crisp in their sound reproduction. I attribute this awesome sound to the 170watts per channel output of my Denon AVR 5803 receiver. While the Maggie's had a wider sound dispersion field the polks focused the sound extremely well within my media rooms set up. The incredible discount on the pair of Polks also sealed the deal. I would highly recommend them..



Elegant, great sound stage

Alex from Florida on 5/24/2017

A fantastic accomplishment by Polk. The cabinet work is so elegant and high quality, as a furniture piece alone, it is worth the money. After about 5hrs of break-in time with some rock and techno pushing the drivers to about 70% max, these speakers settled in and started sounding fantastic and powerful with no detectable distortion on my system. I used only a very clean 80W amp, which produced real soundstage volume. I am used to high efficiency very loud speakers and these did not disappoint. The best part about the sound quality, is the excellent combination of smooth response through low to mid and crisp top end without being abrasive. Seriously the most comfortable speaker to listen to at high volume for long duration that I have ever come across. Superb. The sound has character, warm and attention getting without being in your face like too many other speakers which are far too bright in the 2kHz to 4kHz range or overly muddy on the top end. These are just right. Found no need to run subwoofers with these, the bass response is rich although some may want more subsonic presentation, I think it detracts from the great sound being made by these and suggest listening for several hours after break-in without using subs. The low end vocal range on these are not the best, but most people are not used to listening to that frequency range with great presence unless you have large horn loaded speakers. Still, Sinatra sounds great with these Polk's.

Pros: Excellent cabinets, high quality drivers.

Cons: The mid range driver seems a bit overworked at higher listening volumes compared to the other drivers.


MYKAL from Lodi, CA on 12/16/2016

By Far, the best looking Tower speaker I've ever seen! Looks like it belongs in the 25th Century.

Pros: 25th Century Looks!

Cons: Zero. At this price, there better not be.

My best purchase in years....

Duncan from Sunderland, MA on 11/23/2016

Crutchfield Customer Review (What's this?)

Similar to other reviews I can't believe the clarity of the sound that these speakers deliver; especially, during the soft, slow passages of any music. You would swear that the performer is in the room with you. At a time period when everything is hyped and things don't seem as they appear, these speakers are the real deal.

Pros: Clarity of sound, the cabinets are solid and well constructed and, by the way, beautiful in cherry.

Cons: Not really a 'con' at all....because it speaks to the quality ....but these guys are heavy!

Flawless musical transitions....Polk Audios premier speakers

John from Melbourne, Fl on 11/20/2016

Crutchfield Customer Review (What's this?)

The more I play them, the better they sound. Very high end quality and wood color and finish are flawless. Sound great with home theater system or just playing music.

Pros: Excellent finish, quality construction, and outstanding these for 1/2 price during semi annual 50% off sale.....excellent value

Cons: None


Steve from Michigan on 4/6/2016

Crutchfield Customer Review (What's this?)

Got these along with the 707's as a second stereo set in a very large room. They sound and look amazing. They don't have the punch of the 707's but they still do a great job.

Pros: Sound has lots of detail and clarity. Gorgeous too look at

Cons: Can't think of any

Scratch and Dent

Elston from Seattle, Washington on 2/28/2015

Crutchfield Customer Review (What's this?)

These are quite nice speakers. My 3 star review relates to the fact that I bought "scratch and dent". The speakers came quickly, two days coast to coast. But, the UPS guy arrived early and there they were at the door. The boxes looked just awful. As if they had been through a war zone. Foam was broken up. Card board practically coming off the box. One had a couple severe scratches on the wood at the top. I doubt that I will see it. Crutchfield says you can return, but I would never be able to get these things wrapped and off again. The second speaker seemed new and had the instructions which were missing in the other box. Still, the wrapping was very beat up. Have to wonder if the "scratch and dent" is really demo speakers.

Pros: Attractive. Good sound.

Cons: Packages arrived looking beat up as hell.

Good value for money

Pramit from New York City on 7/18/2014

Crutchfield Customer Review (What's this?)

Impressive speakers with good imaging. I recently replaced my Polk's TSi400 speakers with a pair of cheery colored LSi 705s. First impressions: these speakers are heavy and came well packed. These speakers are not your typical boxy-looking floorstanding speakers. They are beautiful to look at with a real beautiful glossy finish with rounded corners.

Pros: 1. Clarity: I could hear sounds on soundtracks that I didn't hear on the Tsi400s. These speakers have a good frequency range and it shows. I stream Spotify through my receiver and the sound is crisp with good separation of the various components in the soundtracks. 2. Good bass: You really don't need a subwoofer with these speakers since they already come with built-in subwoofers.

Cons: A word of caution: As expected these speakers are power hungry. I use a Onkyo receiver, where as you really need a dedicated amplifier to properly power these Polkies! I am hoping to get an integrated amp for a two-channel setup and perhaps that will make these speakers come alive.

Pure Sound

JWC from Springfield, MA on 10/13/2012

Crutchfield Customer Review (What's this?)

I am a stereo music lover, and after 20 years of enjoying my ADS M12 tower speakers I decided it was time to upgrade to the latest technology. Dolly at Crutchfield was a great help, and I decided to buy a pair of the Polk LSi M 705 towers. They arrived within a couple of days, and despite being deceivingly thin when viewed from the front due to their oval woofers, these speakers perform! I play jazz, rock, and classical, and I enjoy them all LOUD. The Polks deliver huge performance, unwavering clarity, pair beautifully with my NAD 375BEE integrated amp and my Martin Logan Depth sub -- which I cross over at 30-35 Hz because the 705s get down to everything else effortlessly. Dolly was right; for pure listening pleasure and uncompromising quality, Polk is the best value out there today.

Pros: Clarity, power handling, accuracy, wide sound stage, true full audio range reproduction.

Cons: Mahogany is so black they might as well be painted versus real wood veneer. Packaging is very complex and it's almost impossible to keep from breaking and damaging the boxes and foam due to their packaging configuration. Luckily, that also makes them UPS-proof!


Hands-on research

Features and Specs

Enclosure Sealed/Ported
Finish Wood veneer
Color Cherry
Tweeter Ring radiator
Tweeter Size (inches) 1
Midrange Size (inches) 3.25
Woofer Size (inches) 5 x 7
Woofer Composition Super cell aerated poly
Woofer Surround Rubber
Built-in Powered Sub No
Video-Shielded No
Connector Type Post
Bi-amp Inputs Yes
Parts Warranty 5 Years
Labor Warranty 5 Years
Power Range 20-250
Frequency Response 42-30k Hz
Sensitivity 88 dB
Impedance (Ohms) 8
Subwoofer Amp Power ---
Height (inches) 47
Width (inches) 9-1/4
Depth (inches) 15-3/4
Weight 78 lbs

Product Research

Driver Technology
Enclosure Design
Mounting Options

Driver Technology

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 performance levels.
  • Crisp, lifelike impulses, transients & coherent detail without any unnatural ringing or decay.
  • Natural reproduction of complex low frequency instruments & special effects.
  • Uniform sonic representation within the listening area & immersive spatial impression.
  • Reproduce concert/theater levels while maintaining linearity and accuracy.
  • Compatibility with a wide array of electronics both past, present & future.
  • Work as promised for many years of enjoyment (5 year parts & labor warranty).

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.

4-Way Driver System: The Polk Audio LSiM series floor-standing loudspeaker employs a 4-way driver system for crisp, detailed highs; natural, lifelike midrange; accurate, dynamic midbass; & deep, rich bass. The floor-standing loudspeaker houses a 1" Dynamic Balance Enhanced Ring Radiator Tweeter, a 3.25" Dynamic Balance Super Cell Aerated Polypropylene cone midrange driver, a 5.25" Dynamic Balance Super Cell Aerated Polypropylene cone midbass woofer, & two 5"x7" Dynamic Balance Cassini Oval subwoofer drivers.

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.

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.

  • Tweeter/Midrange Crossover: 2.8 kHz, 18 dB/oct
  • Midrange/Midbass Crossover: 280 Hz, 12 dB/oct
  • Midbass/Subwoofer Crossover: 100 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 22Hz to 40kHz & the -3dB frequency response is 42Hz to 30kHz.

Enclosure Design

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, well-defined soundstage.

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.

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 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).

  • 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 floor-standing speaker's binding posts are color-coded (red/black) for easy identification between positive & negative.

Mounting Options

Placement: To enjoy the most realistic stereo image and lifelike sound, place the floor-standing 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.

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).

  • Spiked Feet: The floor-standing speaker includes 4 pre-installed adjustable spiked feet. These adjustable spiked feet allow you to tilt the speaker backwards or forward a tiny bit in order to optimize your listening area. Most floor-standing speakers are adjustable only from the bottom of the base & require you to tip the speaker over using two hands to access the floor spikes. The LSiM floor spikes are adjustable from the top of the base using the included 5mm hex (Allen) wrench.
  • Rubber Feet: The floor-standing speaker's 4 pre-installed adjustable spiked feet come covered with rubber protection tips to protect your hardwood or tile floor. These rubber tips are removable.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Staff Reviews

Product reviews from the Crutchfield Labs

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Q & A

Customer Q&A

Crutchfield asked  
Why did you buy this?

sound, form factor [ Mark  Jul 31, 2018 ]
Have some Polk speakers and like the brand. These are now selling at half-price and Crutchfield notified me of the sale via email. Looking forward to receiving and enjoying them. [ James  May 16, 2017 ]
Polk audio + crutchfield + sale price = instant decision (after months of research) . [ Bruce  Apr 21, 2017 ]
recs and good service [ ROBERT  Jan 23, 2017 ]
My son has the identical speakers and the sale was too good to pass up. [ Duncan  Nov 09, 2016 ]
Matching center from xmas 2014 and good price [ ROBERT  Nov 10, 2016 ]

1 question already asked

Thanks for your question. For information on selecting the best amp I would recommend reaching out to an Advisor by phone (1-800-324-9695) or online chat. They will be able to help determine the differences between the amp models and help you make the best choice for your system. [ Kenny  Jul 04, 2017 ]  Staff