Great info Monk.
My speakers are crossed over at 80hz, which is about right. They are very inexpensive small floor standers (really bookshelves in a bigger box), but I am very impressed with the sound. They are Celestion F20DAs, and cost under $200 delivered. They are very attractive - dark apple wood veneer cabinets, and the tweeter is really quite amazing for the price. The F15 bookshelves are even available at Target now under the KEF label. Here is a review of the F15s, which is very accurate based on my impressions of the speakers' performance.
http://www.stereotimes.com/speak033005.shtml
I note that one user compared with the new Paradigm Atom and liked the Celestion better.
http://www.audioasylum.com/audio/spe...es/246530.html
That's saying a lot, because the Atoms have gotten rave reviews. I have not heard the new atom, but the Celestions seem amazing to me for the price (both in terms of looks, build quality and sound). I was playing them quite loud last night, and they did very well. The F20s are a little on the short side, but they put out quite a big image. I was listening to the Brahms Requiem (Telarc) last night, and it was quite beautiful. The speakers disappeared, and the voices were enveloping and articulate. Although it's a metal dome tweeter, I detected no harshness at all. The only problem is that my old Parts Express sub just doesn't keep up - it's slow and dull sounding.
I am using a Panasonic SA-XR 55 receiver, with digital inputs, and I am very impressed with it. So clean, quiet, clear and natural sounding. It needs about 20 minutes of warm up to sound its best. The amps sound much better than my more-expensive Marantz HT receiver. The lowest crossover point on the Pany receiver is 80hz, which is about perfect for the F20s. I highly recommend this receiver to anyone in the market for an HT receiver with those features. Inexpensive and very good sounding with digital inputs. I'm using it as a stereo amp, but it's got full HT capabilities. I do wish they offered lower crossover points (and came out with a high-powered model), but for typical sub-bookshelf setup it would be hard to beat. I have not yet tried bi-amping the speakers, but the receiver offers a bi-amping capability where two separate equivalent amps would be used for the bass and tweeters. The speakers are bi-wirable. Nice gold plated 5 way binding posts.
I have not heard the HSU bookshelves, but I have read criticisms about the horns being honkey. I'm sure they play very loud, which is important to some, but for me what matters to me is naturalness. So I quickly crossed them off of my list.
I have a similar system upstairs: NHT Superzero speakers, Panasonic SA-XR55 receiver, but with an Athena 8" sub. The sub sounds really good with most music (clean and tight sounding, and blends perfectly), but as I said in my opening post it clips and distorts terribly with low organ sounds. The bad clipping worries me because of the potential for damage. I think it's a problem with the amp in the Athena speakers being underpowered. The super zeros are quite good (a famous speaker in its day), but was picky with positioning and can sound a bit harsh if the environment is not perfect. Also, they require a 100hz crossover as there is no bass at all coming out of them. I've been toying with the idea of getting something better for the upstairs system (possibly Ascend bookshelves). But through a lot of trial and error in placement and some foam padding underneath, 've got it sounding quite respectable.
If you are in the market for a receiver, I recommend that you look into the Panasonic - at least if you're using mainly digital sources. I have not tried analog, but I know it's digitizing the analog signal so there is bound to be some loss there.
I'm very intrigued with the idea of the Hsu 8", but this system is in a very large room, so I'm even considering spending a bit more for a 10". I just want to be sure it will be as musical, because (while I like the sound and feel of low notes) the most important thing to me is going to be accurate performance in the 50-80hz range.