Badly in Need of an Education - Floor Standing Speakers / Center Channel

There are horn designs that don't have the "horn honk" that many find objectionable.

Also, since most horn speakers have compression drivers mated to the horn, they're very efficient-- in the treble. For them to be as equally efficient in the mid-bass, then need a larger woofer, or they sacrifice bass.

For some reason most speakers are designed to cater to people without subs, even though many (most?) people use them WITH subs, the speakers have low enough extension that they CAN be used without subwoofers. 

Hoffman's iron law says you can either have a small box, high efficiency, or low extension... pick two. (or maybe you can have three if you're willing to have a LOT of distortion). There's a sacrifice to be made. So, those narrow boxes that are so cute, with their 5" to 6" woofers, that perversely extend to 40Hz even though you'll use a sub...they are not efficient and many don't give a very dynamic performance. The good ones do, if you throw lots and lots of power at them(external amps required).

So, back to the typical horns...they have too small a woofer to be as efficient down low as they are up high. As you turn up the volume, the woofer gives up but the treble gets louder and can sound harsh. I wouldn't trust a speaker that advertises 94dB+ sensitivity but only has 5-7" woofers, and somehow extends to 35-45 Hz. 

Sensitivity is important to render the high dynamics in films (or use big amps with capable speakers). If you would like to crank it up to 95dB peaks or more (-10dB from reference level), then you might find it starts to sound harsh. This is because the speakers or the amp is distorting. It may not be that the volume, per se, is bad, but that you're wincing at the distortion. Sensitivity and power-handling is less important if you listen at low levels. 

The horn speakers that play in commercial cinemas have 10", 12", 15" etc. woofers!

Lastly: directivity.

If the speaker is known to measure very evenly off-axis, it might be okay to have the sound reflections off the room surfaces. But most speakers have a very different response that's echoing off the room's surfaces and back to your ears, and so this can sound bad. 

The other thing horns deliver besides high sensitivity is they direct more sound at the audience and less at the floor, walls, and ceiling. A little horn on a narrow speaker will have worse directivity than a larger horn on a wider speaker. 

So, for 95% home theater, you may be interested in the high quality, audiophile-quality pro speakers like a Tannoy Definition Install DC-12, QSC KW-122, Chase Home Theater SHO-10, JTR, Pi Speakers 3pi or 4pi or 6pi (can be purchased as kits), or a SEOS speaker kit.  

Here's a list of reference level-capable speakers: https://docs.google.com/spreadsheet/lv?key=0Ahbv22x1GcpqdDdpT0hrNmJVNU5kM0drU0R5bVRNWUE  and here's the thread about it: http://www.avsforum.com/t/1387083/list-of-reference-level-high-sensitivity-spl-speakers/0_50. I'd make sure that the speaker you're looking at will get loud enough using its sensitivity, its program power handling, and your receiver/amp.

If you want the dynamic power, the chest slam of live music, the impact of a great commercial theater, then you need to find dynamic speakers. That's why people here who've bought Revel Salon speakers have moved to speakers like JTR Triple 8's, the SEOS speakers, or the Pi Speakers I mentioned. 

On the list, you'll see some speakers don't get near reference level (105dB peaks) unless you feed them way more power than they're rated to handle. Some will get their within their power handling, like a 300w program power speaker that need 320w might do fine, because it'll handle in most cases twice the program power for short peaks, with varying levels of distortion. Other speakers are sensitive enough they only need 100w receiver, or less. Just depends on your goals. 

• You'll see many pro audio speakers. Some of them are stage speakers, and the cheap ones are probably full of problems, like plastic cabinet resonances, they're often ugly, their horns are just meant to cover the crowd, but they might also sound poor (that horn honk I mentioned earlier). They have to get loud enough and dynamic enough to play live music. I've heard good things about some of the Electrovoice, but I'm not really sure which ones work great in the home for movies and music. 
   
• You'll also see many broadcast / mixing speakers. They have to be accurate enough for the people who are making/designing the music and sound tracks. They have to get to reference level in order for sound designers/engineers to know how it's going to sound. 
   
• You'll see cinema speakers. These always have horns (that I've seen) and the cheap ones roll off at 12kHz, and the better ones 16kHz to 20kHz. They need to entertain a crowd of movie-goers.
   
• You'll see some residential speakers that borrow from pro audio technology and methods: large woofers, horns, etc., but are refined enough for critical listening in the home. JTR, Geddes, Seaton, Pi, Genelec, Procella are some examples. 
   
• You'll see active speakers, where the speaker comes with its own amplification. The amps are perfectly matched to the application, and there's a digital crossover that doesn't soak up power like a typical passive one does. Many studio monitors use this method, as does Seaton, Genelec, Pro Audio Technology, and QSC, among others. 
   
• You'll see typical residential speakers. Some are in the low 90s, like Axiom. Some are in the high-80s, but have big power handling drivers, like Dynaudio. Others are more suitable to medium volume listening.
   

It's really easy to get entranced by the shiny receivers with all the buttons and lights and less distortion than the other or 30w more power. But since it takes TWICE the watts to get just a 3dB increase in volume...well, if you compare the 100w to the 130w, that's less than one dB difference. And the distortion in the receiver is orders of magnitude less than what's produced by the speakers. Consider the speakers and subs the long-term investment, whereas you might upgrade the receiver every 4-5 years for new capabilities. The speakers, and the room they're in, have the greatest impact on the sound. 

The speaker kits I mentioned require very minimal DIY skills. When a kit contains the wood, and you just glue it together and paint/stain it as you wish, that's pretty easy. I have such minimal skills, and I'm doing it, so I know you can, too!

I haven't heard of anyone complaining of a Pi Speakers kit. The owner, Wayne Parham, has been a major force in advancing the state of the art in speakers for decades. 

I hear many people like the Klipsch Reference line, but their sensitivity is over-inflated. I'd pick Klipsch that had 8" or larger woofers, or their Heritage line, or the Theater speakers. 

Hsu makes an intriguing speaker in the HB-1 and their matching center. The horn is not mated to a compression driver, so it's not as sensitive as one might think. The 6ohm nominal impedance makes it more like 90.5dB (if you want to compare to other 8ohm speakers).

Note: the List just underwent some big changes and I haven't yet put in in-room sensitivity and the corrections to account for where manufacturers play fast and loose with the specs. The data's in another spreadsheet I just have to copy and implement some new formulas.

Cheers!