The room is aproximately 14 by 18. Do I position the speakers on the shorter wall, and have the "Throne" at a direct 45 degree angle from each speaker? Does it matter if I sit further back from this "convergence point"? If I put them in the corners on the long side of the room, the 45 degrees from each one aproximately coincides with a seat in the middle of the opposite wall. If it's the other way, it's more in the middle of the room. Any Suggestions?? I know you'd never place conventional speakers this far apart, but they stick out quite aways from the corners.

Ed White

Ed, I have only positioned my Seven Pi on the short wall of my 16 x 20 room, so I can't make the comparison between short vs long. When seated my ears are currently ~5-6' back from the convergence point, althouh ideally I'd like to be a few feet closer. Sitting back to far from the convergence point flattens the soundstage, and makes the performance to far removed for my tastes. Sitting right at the convergence point is more like nearfield listening to conventional speakers. Actually very nice if you like to be immersed in the soundstage. A few feet back from the convergence point gives me the right balance. It will probably come down to your personal preferences. Even changing the angle of the high frequency compression driver can alter the presentation quite a bit, so experimentation is your best bet to finding what works for you.

When the forward axis crosses in front of the listener - as it does in the π cornerhorn - then the "sweet spot" becomes very large. The reason this happens is this arrangement tends to naturally balance stereo imaging. Side to side movement has less of a detrimental effect on imaging than it does in other arrangments because as you move closer to one speaker, you move further off-axis. The more distant speaker becomes closer to being straight on-axis. This tends to balance the SPL between each speaker even when you move from side to side. This has a huge positive effect on stereo imaging.

The pattern from the π cornerhorn is spectrally balanced, uniform across the entire audio band. I know of no other loudspeaker that provides such uniform response at all horizontal angles over such a wide bandwidth. The crossover and the horns used are responsible for much of this, but the room's corner and the speaker's orientation is really key. If the walls from the corner apex continued on indefinitely, then the pattern would remain uniform down to the lowest frequencies but since rooms are confined spaces with boundaries, standing waves develop within the room. This affects how low the energy distribution within the room remains uniform before being modified by room modes.

At midrange and higher frequencies, standing wave modes are so densely spaced that the sound in the room acts as a reverberent field. This is the range where the speaker is able to control directivity. There is a point where the standing wave nodes become spaced far enough apart to become distinguishable, and this is called the Schroeder frequency. Below this point, the room is largely responsible for setting the shape of the sound field. Homes with framed drywall construction usually have reasonably good damping at bass frequencies, but small rooms with rigid walls sometimes have noticeable peaks and dips in bass response. It is often beneficial to add a couple of subs to smooth the sound field in the modal range, to average the energy distribution throughout the room at very low frequencies.

One thing you can do to gain a very good understanding is to use a room acoustics modeling tool like CARA to visualize how the room is energized at various frequencies. You'll see that there are large wide "pockets" where sound is good and uniform across the frequency band. Framed drywall construction and furnishings tend to damp the room and help make bass uniform. Having a 90° dispersion pattern on the sound sources reduces early reflections, and in fact, the walls become flare extensions, making the room and speaker act as a unit having constant directivity. The end result is a natural sound field that sounds good in a large area, not just in one sweet spot.

• Computer Simulation of Room Acoustics

Thanks Wayne. The midhorns have not been sanded and finished yet, the back panels need to be installed, and I need to make a housing for the high frequency horn ... however I'm enjoying them so much I don't know when I'll find the time to complete them.

Michael

Asking you because I thinking of building corner horn as well.