Loudspeakers with a wide sweet spot

Most speakers have a midrange scoop, by this I mean a dip in the off axis response through the midrange. If you want something with a wide sweetspot then you need something with an even off axis response. In a two way this is not easy to find because large woofers "beam". A three way with a small roughly 3 inch midrange like the Accuton on the Eidolon will be a good choice. Omni's will also work if you can pull them far enough out into the room so that rear wall reflections do not have any deleterious imaging effects.

Here is an example of a rare two way that would work B&W N805.

The tweeter is unique and patented. It goes down to 2KHz- well within the range of image definition.

This reminds me of the Energy Pro 22 - they had a hyperdome tweeter that they made themselves and which was crossed over at 1.8 Khz. Great speakers with a lovely natural wide dispersion and very reasonably priced back in their heyday. No doubt Dr. Floyd Toole had some influence on them. Of course, crossing over a tweeter that low has its problems in terms of maximum SPL without distortion and compression and potential to "blow up" but for a bookshelf the Pro 22's were outstanding sound for their modest price.