Beaware.. These are not true biamp capable. Everyone thinks that you can hook these and the 705 model up to 2 amps and yes you can.. HOWEVER> What polk wont tell you and its nowhere to be found anywhere in a manul or internet, is that the 2 large woofers at the bottom are wired together with the midbass in the middle. The lower speaker connector powers these speakers only. The Upper speaker connectors on the rear of the enclosure is only for the small midrange and tweeter.. SO what does this mean? It means if you try to control the volume of just the bass, thinking you want to use these as some sort of separte subwoofer, main speaker setup like everyone else thought, it wont go so well. When you increase or decrease the volume to the woofers, the midbass will all increase or decrease messing up the entire soundstage. I was able to rewire mine. In fact I took the passive crossovers out and slightly modified them and made mine so that the 3 upper drivers are all by themself and can be connected to an Surround unit for the main speakers and the bottom woofers are soley for deep theater bass which all can be crossvered seperately.. Major work to do this becuase the woofer and midbass crossover is all on one crossover board behind the upper woofer. However the new wiring I managed to create is absolutely amazing and the bass coming out of these and the 705's is the best bass I heard of any towers and many stand alone subwoofers. Let me be clear, these are not for biamping. You go trying that and changing the volume on each amp, it wont go so well. Bi amping these after you rewire them internally is a whole new story but most people have no clue how to even do that.. soo good luck

The Polk forum has several rude and abnoxious users. When I tried to contact Polk to get the schematics for the crossover Polk said NO. I also tried on the polk ofrum and was met with a very rude set of members mainly the one everyone knows about and there is a video on youtube making fun of this idiot. Polk would be well to get rid of such members quickly and efficiently and start offering manuals to costumers like most other companies. I will not purchase another priduct from Polk becuase they made these speakers with a really bad crossover design and did not allow me to see the schematics to i can fix them . Even after I purchased these! After I modified them through a very long trial and error of looking at the crososvers, measring them with meters etc, I was able to properly wire them and they sound very good. Otherwise these are decent but not what people regard them as. probably why they sold them all for less than 60 to 70 percent off price recently. People didnt want to pay the price of these! Also packaing was bad and most customers recived them busted. Hope Polk learns from this info and people heed my warning..

Residing in a small 12’x11’ dedicated music listening studio, the 707’s are dream speakers because they do what many speakers don’t and that is “disappear”. Closing my eyes the first time caused me to catch my breath also. The speakers were gone and the music alone stood in front of me. It was a trip! All genres of music are on my musical palate and all are wonderfully rendered. Rock, blues, R&B, folk, Latin Jazz, classical, hip hop, etc. All enthralling. My source material is typically CD or streaming. No issues with vinyl, I simply have been there and don’t have the storage space or patience for turntable, tone arm, and cartridge/stylus dickering. But I bet it would be drop-dead gorgeous on these speakers. They aren’t capable of anything less it seems. I am powering the 707’s in my stereo set-up with an Emotiva PT-100 pre-amp and A-300 power amp (150W/ch@8 ohms). It is a dream musical team for sure but the 707’s allow the electronics to show off what they can do. And because of the speakers, it all disappears in favour of the music.

Don’t know as yet.

I concur fully with CR Westerman's review. This is the best audio I've heard in decades. I paired my new Polk Audio LSiM 707's with a new, modest, recently-released Onkyo A-9110 integrated amp. You'd be astounded by the clear soundstage this combination produces. A more powerful amp is useful only if your neighbors, partner and building walls can take it.

none that I have found

I have bought and built speakers for nearly 50 years. I have owned the following speaker brands: JBL, DCM, Infinity, Polk, Magnavox, Cerwin Vega, Yamaha, Pioneer, Sunfire, Dayton, Audax, Vifia, Lafayette and Altec Lancing. I have also listened extensively to Klipsch, Definitive Technology, Advent, Bang and Olfsen and Bose. Most brands serveral models. Building speakers gives you a good idea of what type of speaker will please your ears the most. I've built many but I've never gotten my designs to sound as good as the Polk LSiM707's I own now. I will add that I haven't bought any speakers that were as good either, even tho I've spent more. I was pleasently surprised by several design elements of the Polks: Never would I have believed the oval woofers could be so powerful. The ring tweeter, a design originating back in the early days of hifi now brought back to the fore-front of audio design. Ably combining the sealed cabinet design of the upper drivers with the ported design of the woofers. Evolving the implementation of the 'plastic' drivers and eschewing the exaggerated benefits of metal/ceramic materials. Building the complex box in China to an exacting degree of fit and finish. If a person shopping for a set of speakers were to let their decision be guided by a belief in eliteism, be it the use of so called 'advanced' materials, 'exotic' designs and/or god forbid 'price paid,' they might read about the Polk LSiM707 and take it off their shopping list. What a terrible mistake that would be. Who would have thought combining all of the above would result in a finished product of such desireability. Kudos to those people at Polk that could conceive such a speaker. Do I really need to tell you about all the characteristics that make this such a fine speaker or have I elaborated enough already? No? Ok then... I was worried about the lower limit desiginated by Polk as 38Hz. I wondered why Polk wouldn't have built them to reach the lowest octave of the bass region, after all they are a 'flagship' design. Set your mind at ease, Polk knows what they are doing. The speakers -3db point may well be 38Hz but room coupling extends that figure far lower with all the authority you could desire. For music no subwoofer necessary....at all. Explosions and other effects in movies normally handled by your subwoofer(s) should continue doing their duty. Not because the Polks can't handle it but what are you gonna do, sell em? Not exactly measurable but definitely perceptible is the wide soundstage. My son-in-law's initial audition went like this; He moved from a relaxed position on the couch to perched on the edge as the music played. We were listening to a short intro by Joe Bonamassa. Before the second track began to play, he asked me if I had upgraded my surround system electronics. (I personally don't care for any such effects while listening to music, prefering instead to listen in stereo.) I answered telling him we are listening to a favorite vintage Sansui amplifier of mine that was built before anything was known about surround. He looked incredulous at me and said, "but I could hear sound coming from all the way across the room." I said, "Yep, thats a property of the recording being reproduced by speakers that don't throw that information away." Needless to say he insisted on hearing more. I obliged. In my rush to listen to my favorite music through them, I have discovered several distinctive traits the speakers display. The percussive part of the key strokes on a piano are what makes it sound so real and live. If you have heard someone say this and you haven't actually experienced it, you have a real treat coming. Their ability to portray the suddeness of percussion instruments has me enthralled. One of my favorites is the Hell Freezes Over version of Hotel California. The 'lead in' gets to me every time. My taste in music is wider than most folks, given that, it is no wonder I have a copy of The Dead Can Dance - Into the Labyrinth. The vocalizations are exqusite but listen for the Maracas about 4 min into Yulunga. They absolutely come alive. Throw on Itzhak Perlman and feel the emotion drawn out of you by the sweetest most melancholy, haunting, and extremely evocative sound you will ever hear. Yes, I'm talking about the very best reproduction of a violin imaginable. Tonally, I am so satisfied. Pump up the volume and watch the power meters. At ear bleed levels the meters must be lying, they are only reading a few watts, ten or so. The speakers sound as tho they could care less, crank it on up if you please. Now my better half is at the door saying something I can't make out. I am trying to read her lips. I reach for the volume as she is closing the door and I hear her last couple of words..."the neighbors!" This model is a four way system. Operating each of its drivers in the octave band(s) where they do their very best and it pays off so very well. The largest of the upper drivers (6.5") delivers the chestiness that a deep male vocal has, endowing it with the realism that gets so over done with a larger driver or left out with a smaller one. Talk about the Goldilocks syndrome...it's juuuust right. My favorite of all, the small mid replicating what I listen to the most.. the female voice. Put Sarah Mclachlan on and sit back for the ride. The Polks will blow your hair back as they focus your attention on her uniquely excellent voice. Do it again with Dolores O'Riordan as she sings Ave Maria with Pavarotti. Close your eyes, you are in attendance, at the performance, in the audience....wow! Feels real. The Polks get so much right they don't have any problem repeating what they are capable of each time you call on them to perform. Do they have any faults? They might but I haven't found them as yet. Are they the last word in audio? Probably not, but they may as well be, because I'm not likely to ever replace them. I'm lucky, I can accommodate both a dedicated listening room and a home theater in seprate rooms, allowing an optimization that is beyond the compromise of both systems being in the same room. I highly recommend this Polk Model LSiM707.

The Polks reside in a rectangular room 20' x 12' x 8' with wall to wall carpet a lightly textured ceiling and sheetrock walls. Furnture is a single over stuffed couch with seating for three people. Speakers sit in front of the short wall with a window centered in it covered with 1" venetian blinds. They are 3' from side walls, 4'' from front wall, 6' apart and 9' from listening position. I originally had them 5' from the front wall, still trying them in different locations to see what sounds best. May try putting them along the long wall next. Source components are Aquos Bluray Player, Sansui FM Tuner, Toshiba laptop playing HD files through a Gen1 Dragonfly and a restored vintage Teac X1000-R reel to reel. Amplification is by a restored vintage Sansui capable of producing 125watts/ch @8Ohms.