Here it is:

I'm looking for recommendations on DIY corner horns. The room in question isn't very large (11.5' x 12', with 8' ceiling) so there isn't much room for speakers to be placed out away from the walls. As such, I figured that corner horns may be a good solution. So, any recommendations?

Size is still an issue, as the speakers can't protrude into the room very far. I like tight bass (not boomy), and good mid-range reporduction, and I'm not to worried about the high frequencies. I'm more interested in bass range and accuracy than outright bass levels. Basically, the highs and lows can roll off a bit (but not too much). I plan to build an active parametric equalizer to use as a room correction device anyway.

I listen to Rock, Jazz, and Classical so the design would have to be versatile. The speakers will be driven by a push-pull tube amp of about 12W that will be feed by a Foreplay linestage. CD source with a turntable to be added later.

Any help would be appreciated. Thanks.

As far as acoustics are concerned, what you have is small enough there is pretty good room gain, like what you get in a car. On the down side, the furthest you can place speakers apart is twelve feet, unless you place them in diagonal corners, which I don't like to do. At twelve feet, you have 1/2 wave cancellation between speakers at 50Hz. If you place them a little closer together, say 10 feet, then the 1/2 wave notch is at 56Hz. You have 1/4 wave self-cancellation from an opposing wall back to the speaker at 25Hz, but that's pretty much out of bounds. These are issues you'll have whether the speakers are cornerhorns or not.

Here are some good articles about room placement that you might find useful:

• Loudspeakers and Rooms for Multichannel Audio Reproduction, Part 1, Floyd Toole
  
• Loudspeakers and Rooms for Multichannel Audio Reproduction, Part 2, Floyd Toole
  
• Loudspeakers and Rooms for Multichannel Audio Reproduction, Part 3, Floyd Toole
  
• Sound System Design Reference Manual, George Augspurger

If you have the room, go with the Audiophile or Professional Series seven π speakers. For a little less money, you might look at the Stage Series seven π or the Theater Series six π speakers. The eight π might be a good choice for you too, because it can be placed in corners or against walls. And if each of these are too large, you might look at tower two π speakers instead.

On the other forum it was mentioned that I would need 6' of unobstructed wall to either side of the corner horns for them to work properly. Is that the case? I won't have 6' of unobstructed wall.

Also, the speakers will probably be placed on the 11.5' wall. If the bass is cancelled at about 50Hz (which I assume means there will be a noticable dip in the response at that point), would it be better to restrict the bass output to about 60Hz and then add a dedicated sub to handle 60Hz and lower? I'd rather not go this route, but it sounds like I may not have a choice if I want good bass extension.

I didn't want the speakers to intrude more than about 16-18" (measured directly out from the corner, 45 degress off each wall) into the room. I can reclaim the space (and increase the wife acceptance factor) by using the speaker as a shelf (I know, blasphemy) or by adding a shelf directly above the speaker.

Right now I'm to the point where I'm trying to decide between an Adire HE10.1 setup or the Pi corner horns. My main objective is to build some great sounding speakers don't need to be place out into the room to sound good and that don't take up a lot of space.

Your room is going to provide a good deal of room gain. Even small loudspeakers will probably sound like they are providing deep bass. The room will actually help you in this regard. But boundary conditions will create some standing wave phenomenon, no matter what loudspeaker you chose.

If it were me, I'd probably go with two π towers. I have a pair in a room very much like yours, and I have each placed at opposite ends of one wall about a foot and a half from the corners and about 4" away from the wall.

But I've also put seven π cornerhorns in rooms this size and they sounded very good. You can listen to them nicely from just a few feet back, and in spite of the room's size and the issues that causes, the sound is very good. I have a pair in a room that size right now, with one corner completely wrong. I just don't have another place to put them. They still sound glorious.

having speakers placed directly into the corners doesn't give me a lot of flexibility when dealing with room resonance. Also, the fixed 45 degree angle of the corner horns doesn't leave much room for flexibility either.

What happens if opt for the 7's and build an asymmetrical horn? Basically, taking the existing design on rotating the bass enclosure a few degrees while leaving the corner section at 45 degrees.

This is starting to look like quite an engineering challenge.

A guy on the other forum said that I would have a problem at about 57Hz. If that is the case, then my (rather uninformed) guess would be to have main speakers that cut off at, say, 60-70Hz and then use subs to do the rest. Assuming that's the case, would Pi have a solution? Or am I just creating other problems and making this even more complicated for myself?

You can certainly use a pair of small speakers like two π's and add a single subwoofer, crossed at 60Hz. You might position them where nulls from cancellation are counteracted by the sub or by boundary reinforcement. It depends on what you want, what you expect and to what extent you are willing to go.

I suggest maybe you might try a pair of two π towers first. The kits are inexpensive and perform very well. The cabinets are easy to build. That will give you something to work with, and is at least a good starting point. You may find that's plenty for you, and decide you don't need to go any further. Two π tower's aren't cornerhorns, but they are nice speakers that sound good in rooms your size. You can listen to them a while and decide if you think you'll want a sub later.

My preference is a single pair of speakers, but I'm willing to do whatever I need to to solve the problem. The carpentry isn't a big deal to me, so cabinet complexity isn't an issue (I've built a pair of Fostex based back loaded horns and some self-designed bookshelf monitors). The corner horns have the most appeal because they meet most of my requirements. However, the falter in that they don't allow for compensation of room interactions. So, if I could 'magically' eliminate standing waves and other cancellations, the decision would be an easy one for me. Basically, I'd like to be able to end up with an installtion that doesn't have an installed frequency response that looks like a mountain range.

Please don't think that this is an insurmountable problem. We probably shouldn't be focused solely on the distance between speakers in your room; I merely brought it up because the distance along one wall was less than 18 feet, which meant that if speakers were placed at opposite ends there would be 1/2 wavelength between them somewhere in the bass range. It is just something to think about, and probably you shouldn't base your whole installation on it. Otherwise, you can't even get started because the furthest you can position speakers apart in your room is only about 16 feet, at opposite diagonal corners.

There are other placement conditions that cause the same sort of condition as placing two speakers 8-12 feet apart. For example, when a speaker is raised 4 feet off the ground or pulled 4 feet from a wall, this creates a notch at 70Hz because of self-cancellation. The reflection from the surface makes the wave travel 8 feet back to the source, which is nearly the same distance your speakers will be from each other. It's the same sort of problem. But look at how many people prefer to put their speakers on stands or bookshelves.

Honestly, most people don't notice 1/2 wavelength bass cancellation from a pair of stereo speakers in a small room like yours because there are other effects that mask it. The room is so small, it tends to become pressurized uniformly inside and bass seems to be stronger. And also the room isn't a perfectly sealed loss-free system. North American homes typically have drywall with R13 insulation behind them, and this tends to damp standing waves to some degree. There are also things in your room that will also absorb sound and interact with the loudspeakers. All this makes the acoustic environment something between reflective and anechoic. So I don't think you would hear a null in the center of your room.

If you did find a null, you could always add a subwoofer later. You'll need a pair of speakers anyway, so you might as well start off with a good pair and try them out first. If you think the bass is missing at 50Hz, go ahead and spring for the sub. But I don't really think you'll be lacking for bass, unless you choose speakers that have weak bass output. Tower two π's have good strong bass and balanced mids and highs. Seven π cornerhorns are very nice, and you surely won't be wanting for bass with them.

Honestly, I think you would be very impressed with π cornerhorns, even in your small room. It isn't ideal, but rarely do people have ideal rooms to work with. π cornerhorns would probably work very well for you. They might be overkill though. If you have the budget, go for it. I'm confident you wouldn't be disappointed. But on the other hand, I think that a very conservative approach of starting with the entry level two π tower speakers would probably be very enjoyable for you. They are inexpensive and very nice.