Speakers with wide listening window

As others have suggested get a speaker with good off axis response.

Think of speakers as lights. Most designs are like a spot light. A few are designed with wide even dispersion that makes the off axis match the on axis - a flood light.

What to look for? Take a look at Stereophile frequency plots where they show the on and off axis response for various degrees. Look for a design that is even and smooth both on and off axis.

Example of good "flood light" response

Example of Bad "spot light Response

Notice how the bad response had a huge hole in the midrange off axis. This means that with this design you will only get an even response when sitting close to the speakers and in the sweetspot.

Audioconnection wrote:

"...the only way to get a wide listening window is to use a speaker that is so defuse that it can't possibly have a "sweet spot". The higher resolution and more transparent a speaker the smaller and sweeter the sweet spot. It is simple physics primarily because there is only one spot where the listener is the same distance away from both speakers."

What you're overlooking is that the ear localizes sound sources by TWO mechanisms: Arrival time AND intensity. If we can make the far speaker louder than the near one for off-centerline listeners, we can offset the earlier arrival time of the near speaker, and deliver decent soundstaging for off-centerline listeners. The way to do this is with controlled directivity and proper setup, and the end result is much more effective than simply using a diffuse speaker. This sort of setup will work better for some listening postions than for others, but will never be worse than the diffuse speaker for off-centerline listeners, and will still give very good imaging for listeners in the traditional "sweet spot" because of significantly reduced early sidewall interaction (due to the relatively narrow pattern and strong toe-in).

Duke

I do something similar to what AK is saying with my Dynaudio monitors to make them perform more similarly to my more omni OHMs in one of my rooms where I have the placement tweaked for off axis listening.

I would seriously consider the Shelby+Kroll Nano monitors. I've had these now for almost a week and the soundstage is phenominal, it just follows you around the room. I was even listening behind the speakers and didn't notice a significant difference and mine aren't even completely broken in yet. I've been listenting to mine with a cheap Yamaha receiver and can only imagine how much better they would sound with better electronics.
I would contact Tim over at Shelby+Kroll They may have some B stock remaining. He's a great guy to deal with and I doubt you could do much better in this price range.

Ohm Walsh are very good at this.