The reason I toe in my speakers is because when off-axis the higher frequencies drop off. Paul Barton at PSB Speakers showed me this some years ago. His site gives off-axis numbers for all his speakers. For instance, the PSB Alpha speaker on axis is 55-21,000 Hz while off axis is 55-10,000 Hz. Off axis cuts to half the higher frequencies.

YPAO and Audyssey will measure speakers as to tonality, distance, and frequency range relative to the mike placed in the seating position but if the speaker is off-axis to the mike a false rating occurs. Those speakers that aren’t directional (dipole or bipole surrounds) can be measured off-axis but they were never meant to be heard on axis.

And yes, toeing in speakers does alter the room characteristics. One day, when I win the lottery, I am going to build the perfect sound room and attach a house to it. Until then I have to put up with a room that, at about 3,000 cubic feet, can be, ahem, daunting. Like all suburban homes it’s wallboard 15x27x8 and it does have a reverb that inherent. However, with the speakers toed into the seating area all the changes I have to make are to the room itself (cover hardwood floor with a scatter rug, that sort of thing).

The other is subs and their effect in corner echo. As everyone when I got my first subs placed them as recommended in the corner but was never satisfied with the bass until I moved them away from the corner. I also had my mains too close to the wall and they too sounded better when I moved them away. The only speakers I have that are close to the wall are the dipole surrounds – but I have then set to small so they handle little bass.

MichaelR