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Polk Audio LSiM 707 Flagship Floorstanding Speakers First Look

These are about 1000% prettier than the old LSis in our opinion

These are about 1000% prettier than the old LSi's in our opinion


  • Product Name: LSiM Floorstanding Speakers
  • Manufacturer: Polk Audio
  • Review Date: January 05, 2011 01:20
  • MSRP: $TBA
  • First Impression: Pretty Cool
  • All have 3.25" Extended Liner Motion (ELM) midrange mounted above a 1" Advance Isotropic ring radiator tweeter
    • 707 towers add a 6.5" ELM mid and two 6x9" ELM subwoofers
    • 705's towers add an additional 5.25" mid and two 5x7" ELM subwoofers
    • 706c center adds two of the 6.5" mids on either side of the array in a a ported design
    • 704c center a 5.25" mid on either side of the array
    • 702f/x surround model an additional tweeter and a ELM 6.5” mid-woofer driver with a proximity switch to optimally compensate for placement near corners
  • Driver Features
    • Super Cell Aerated polypropylene cones
    • Cast aluminum driver
    • Butyl rubber surrounds
    • Magnetic, non-diffracting grills
    • Easy-leveling floor spikes
    • Rubber trims around the driver baskets

You put two words together in the same sentence and you are guaranteed to get every Audioholic's attention. Those words - Flagship and Speaker. Add "new" in there somewhere and we'll be falling all over ourselves trying to find out what you're talking about. While we love media servers, displays, and gadgets, there is something about speakers that we can't help but get excited about. Maybe it's the fact that we're Audioholics and not Videoholics. Maybe it's that nothing gets as little attention in the media as speakers which are almost glossed over like a distasteful if necessary part of home theater. With so many manufactures moving to "i" products designed to look rather than sound good, seeing a manufacturer spend a little time and a lot of money on a new speaker designed to bring us new levels of sonic bliss hits us right where we live.

Polk Audio looks to be doing just that.

For almost ten years Polk Audio has had the LSi line as their flagship speakers. This year, at CES, they are introducing a new flagship, the LSiM (or LSiM or LSi M, the press release has all spellings - maybe they are still working on the name?). The new line will have floorstanders, bookshelves, a centers and surround channel models. No word on a sub yet. So far, the LSiM 707 and 705 are the two tower speakers that have been announced with the LSiM 707 being the top of the line. 

polk_driverThe core of the LSiM line will be Polk's proprietary 3.25" Extended Liner Motion (ELM) midrange mounted above a 1" Advance Isotropic ring radiator tweeter. Polk claims that combining these transducers in a single optimized array produces an uncommonly wide and uniform dispersion pattern. Each of the speakers will have this array with the 707 towers adding a 6.5" ELM mid and two 6x9" ELM subwoofers to the mix. The 705's will add an additional 5.25" mid and two 5x7" ELM subwoofers. The LSiM 703, the bookshelf modes will use the same drivers as the towers without the subwoofer drivers (we're not sure if they'll have the 6.5" or 5.25" midrange. The towers are definitely ported (it looks like downfiring ports into a baseplate) though no word on the bookshelf as yet.

There are two center channel models planned for the LSiM series. The larger LSiM 706c has the same array as the other speaker with two of the 6.5" mids on either side. This speaker should mate well with the 707 towers (one wonders why they didn't go with 707c but whatever). It is a ported design, something that can make in-cabinet placement difficult unless Polk opted for front ports. The LSiM 704c is the center counterpart of the 705 towers with a 5.25" mid on either side of the array. The LSiM 702f/x surround model completes the series for a multichannel setup, offering a ELM 3.25" mid-range, 2 x 1.0” AIR ring radiator tweeters and a ELM 6.5” mid-woofer driver. The 702f/x also includes a proximity switch to optimally compensate for placement near corners in the listening area. No word if this is a dipole, bipole, or selectable speaker.

The drivers in the the LSiM line feature Polk's Super Cell Aerated polypropylene cones that reduce mass. Driver baskets are built from cast aluminum frames that provide superior rigidity. Butyl rubber surrounds ensure outstanding linearity through many years of trouble free performance. Finishing touches include magnetic, non-diffracting grills, easy-leveling floor spikes and rubber trims around the driver baskets that create a cosmetically clean fit and finish. While there is no pricing set on the new LSiM line, the old flagship models rang in $1500 each for the top of the line towers. You have to expect something north of that for the LSiM 707 towers.


We have to admit, we love the look of these new speakers. They are a great deal more attractive than the LSi line which was boxy at best. The curved cabinets and gloss black fronts definitely have our attention. And honestly, when you are spending this sort of money on a speaker, you want something that looks good. Makes selling the idea to the spouse a heck of a lot easier. Of course, it doesn't hurt that Polk has a lot of technology behind the speaker. While they love to call normal design options silly things like "Polk's Dynamic Sonic Engine enclosure ," and "Polk's PowerPort®" (if you don't plug it in, it's a bit misleading to call it "power" anything), we'll forgive them. There marketing department has to do something other than Sudoku right? We might also take issue with the idea that the flat woofers on the towers are sub drivers rather than woofers but again, marketing department. The fact is that these look good and look like they'll sound good. We can't wait to get our hands on a pair to try them out. 

Unless otherwise indicated, this is a preview article for the featured product. A formal review may or may not follow in the future.

About the author:
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As Associate Editor at Audioholics, Tom promises to the best of his ability to give each review the same amount of attention, consideration, and thoughtfulness as possible and keep his writings free from undue bias and preconceptions. Any indication, either internally or from another, that bias has entered into his review will be immediately investigated. Substantiation of mistakes or bias will be immediately corrected regardless of personal stake, feelings, or ego.

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