After writing earlier this morning on the positioning of speakers, I adjusted mine just a hair more here and there, and saw even more improvement. I then drew-up this diagram. It's not scientific at all. But I used the purple wedges to show sound coming out of the speaker. It may in fact not widen as it travels; it may also be wide as soon as it comes out. A course in physio-acoustics would be in store for me. But the lines show how I aim the speakers. The left speaker is aimed to the right-most part of the sofa, the opposite for the right speaker. What I've created is a type of criss-cross of direct lines. I swear to my maker I can hear the cellist right now (happens to be Chrisophe Coin performing Vivaldi sonatas with Christopher Hogwood) right in the center of the two speakers. And he's in the middle of the room. My guess is... the closer your speakers are to one another (back, green triangle) the less toe-in that is required. The further apart, the more toe-in.