Well, we're coming up on 48 hours of me having the LSiM 703s in my custody, and quite frankly, I don't wanna give 'em back! They're amazing! I promised a review in the thread for our meet-up, and would have liked to have had more time with them but the threat of having to send them back is looming close and I want to share these with other TX Polkies, so I'm going to write this review while I listen to them. This is my first time critically reviewing a speaker, so bear with me as try to walk you guys through my experience so far.
First off, I'm just in love with the new cabinet design. Not that I have a single thing against the look of the LSi line, but the smooth curves are elegant but not overbearing (and are backed by equally-smooth sound, but we'll get to that later). The LSiM's cherry is very similar to the tone of the LSi's, but different enough to notice when placed side by side for comparison. It would be a lot tougher to tell if you had a set of Ms in one room and LSis in another. Since these are pre-production models, there's no way to tell if that will permanently be the case. I've included a picture to illustrate the difference for those of you who are curious. I think it would be cool if they would also include a lighter color like a natural birch, but I'd be content regardless of the color\ The grills are held on by six magnets, so the front was able to be kept smooth, beautiful and sans grill-mounting-holes. "polkaudio" logos are mounted at the bottom of the speaker, and serve as an additional support to hold the grills up, not that they really need it, but they do come off a good bit easier than your plug-socket style grill mounts, so without the emblem there I could see the grill easily being knocked off. These babies are without a doubt designed for grill-less action, but still look gorgeous with the grills on, so those of you with the curious kids need not worry that you'll be missing out with the grills in place. As far as cabinet integrity goes, Polk did it right and built in some solid cross-bracing, which will keep the cabinet walls pretty damn inert. The bracing in addition to some light polyfill stuffing and curved walls should keep standing waves to a minimum, further improving the sound of these over the previous generation. The backs of the speaker are graced by good ol' PowerPorts, and metal terminal plates with much nicer binding posts than before. Instead of using metal-tab style jumpers, Polk has supplied a short cable with loop ends that slide over the binding posts and are secured when the binding post is screwed tight.
For those of you who in the tweaking crowd who, this means doing a plate with 3 sets of binding posts for an external crossover will look right at home, but these speakers sound pretty damn sweet as is, to the point where even I'm not considering modding mine when I get them, at least not for a while. Also, since the bass driver has been stepped up to 6.5", there will be more room to fit in a modded board internally so the lower-value ClarityCaps etc. will be easier to maneuver into the cabinet.
On to the good part... how do they sound?
The highs are incredibly crisp and detailed. Polk has successfully bridged the gap between the brightness of RTi/RTiA line and the laid-back sound of the LSi. They have better clarity than my modded LSi25s, and more impact than my JBL Northridge E50s. Today's the third day in a row I've listened to LSiMs, and I have yet to experience a single hint of ear fatigue at higher volumes. The imaging is killer, the soundstage is wide, but the depth hasn't sent me checking my remote to make sure I'm in 2-channel mode like my modded LSi25s did. IMO, it's a little unfair to compare them to modded LSis, because those are so much of an improvement over the regular LSis, but I'm just trying to give a completely honest rewview. Now, I'm still not sure if this set of 703s is broken in or not, or even how much playtime they have, and if they're not, I'm sure that could affect the depth some. Considering the fact that these are pre-production models, I'm going to assume it hasn't had a lot of good break-in time and take that into consideration. I've only played them at softer volumes the past two evenings and haven't had any good "break-in" time since I haven't had the house to myself, but today it's all mine and I'm letting loose. Back to the good stuff, the LSiMs blend extremely well from highs to mids to midbass (and to bass in the case of the 707). The midbass has been a very pleasant and welcoming surprise. The first thump of "Hotel California" on the Eagles' Hell Freezes Over album had me scrambling to check my receiver's settings to make sure I had the subwoofer out switched off, and it indeed was... They relentlessly pound me in the chest with a firm midbass impact, but it wasn't the slightest bit muddy. Even at higher volumes, the sound doesn't deteriorate the slightest bit. My system's future includes an LMS Ultra 5400, and prior to today I was worried that I might have to buy some 705s to get enough midbass impact... hah! No need. The 703 have it. Now in a larger room, the 705 would probably be a better solution, but my HT room is no more than a glorified bedroom. Now if you want the full experience, I'd pair these up with a sub crossed somewhere between 70 to 80. When I coupled these with my PSW1000 crossed at 80, it brought back the recent memory of experiencing the 707s. They play pretty damn deep as-is, and make a great standalone set, but they are without a doubt missing the ultra low gut-punch supplied by the towers, which is to be expected of a bookshelf speaker. A MicroPRO 3k or 4k would be a great match, or any of the higher-powered subs from other manufacturers or past lineups.
To sum it up into one sentence: they're designed well, built strong, have a beautiful finish, and a sound signature to match all of those characteristics.
For reference sake, I put them through their paces with a variety of music including Apollo 13, The Eagles, The Verve, Santana, Richard Cheese, David Allen Coe, the scores from Halo 2, 3, and Reach, Hans Zimmer, John Mayer, Coldplay, Dave Matthews, Enya, Blue Man Group, Prodigy, The Chemical Brothers, The Crystal Method, The Beastie Boys, Lynard Skynard, Joe Satriani, Timbaland, Ludacris, The Fray, Eric Whitacre, and I'm sure there were a few more that I didn't remember to write down. Nonetheless, I want you guys to know I put these through quite a few genres to get as detailed of a picture as possible.
Associated gear for a vast majority of the review: Pioneer Elite SC-37, Monster Cable XP speaker wire, Polk Audio PSW1000, 24" stands, my laptop with the X-Fi soundcard, my iPhone (via USB to the receiver, not via the audio jack), and Crown Royal . I also did some minor listening on my bedroom/computer rig, which consists of my laptop & X-Fi card, HK 3480 and AudioQuest Type 4 speaker cables (the EQ was not used).
I'll post up more pictures if anyone wants. I took a TON of them so there's plenty more angles etc. My computer is being kinda retarded so I decided to stop at four today.