Tvad makes a very good point.
The CS2's right now have a lot of buzz and much of it stemming from a very good showing at this year's CES. I had one friend, a dealer, who picked up the line after the show. However, I'm not sure they are worthy of the hype.
I think the CS2's are an ok pair of speakers and the price is pretty fair given the usual difference between cost of manufacturing and final dealer price. I estimated that I could build a pair for about $1200 so the $3.5K is about right.
Except for using the DSP on the Behringer for fixing the bass problem, the CS2's break absolutely no new ground(and even that is not new in DIY circles). A two way speaker using a compression driver and a horn for the mids and highs and an open baffle for the bass goes back over 70 years. (let's avoid an argument over the semantics about whether a waveguide is a horn or not) Do a search for the old Western Electric 'Wide Range' speakers designed in 1931. Altec and JBL made their reputations on similar designs (albeit with bass reflex enclosures for bass and not open baffles).
I do find that speakers using this geometry when done right are very dynamic with smooth sound through the mids and highs. Of course, most horn fans will say I told you so. Compression drivers are incredibly linear and sound unbelievable when coupled with a properly designed and implemented horn.
The CS2's try very hard to cheat the laws of physics. As I said, open baffle bass go way back. They were used before bass reflex enclosures and certainly way before sealed enclosures. However, the drawback to an open baffle is the cancellation due to the rear wave. The way to defeat this naturally is to use a wide baffle. Check out the JElabs page about open baffle speakers. http://members.myactv.net/~je2a3/open.htm
But people want bass below 40 Hz and want their speakers small at the same time. i.e. trying to beat the laws of physics. Hence the use of equalization. DSP is essentially advanced (or not) equalization in the digital domain. One of the main problems I have with the CS2's is that I hear the digital artifacts introduced on the sound by the crossover. Several of my friends hear the same thing. Of course, everyone hears and likes different things so YMMV. The benefits from an open baffle hardly outweigh the negatives from a digital crossover especially if you listen to vinyl.
In my experience with the CS2's, I found the sound very odd and unnatural. My dealer friend gave me a frantic call one day because he received his speakers but they sounded very bad using the stock programs from the factory. Very different than at the CES show he told me. I went to his store to help set them up. With his electronics, I had to use a very different crossover program to get them to sound right. The stock programs did not work at all. Another friend did like them at another dealer but the other dealer also tweaked the stock crossover program. Maybe the pair I heard was just not set-up right. Still no amount of set-up was going to fix the vibrations from the plastic waveguide (aka horn).
I would suggest listening to other speakers that use a horn mid/high and a dynamic cone for a bass before buying the CS2's. In my opinion, the CS2's are not bad but other speakers using a similar geometry sound far better and use much better quality drivers. The CS2's are a good buy money wise because they use pro audio compression drivers and bass drivers. Effective and cheap but you can do much better. A JElab style open baffle using Great Plains Audio 604H-II drivers cost about half the price of the CS2's and sound much better and only need one amp. $3500 is not a bad price but you do need to factor in the cost of a second amp. You could buy a used pair of Altec Valecians, Altec model 19, JBL 4330 monitors, etc. for less than the CS2's.
If you are interested in open baffle speakers, check out speakers based on PHY-HP drivers which are designed for open baffle use. (Ocellia, Auditorium23, Musical Affairs) If these are a bit pricy check out the offerings from Hawthorne Audio (http://www.hawthorneaudio.com/index.html).
It is better to do a bit of homework before putting down the cash. Of course, if you really like them then get them. Utimately, each person has to decide what they really want.
