Surround speaker location for music?

Is it best to be in line(90 degrees) with the listening position or a little behind the primary listening position? I am planning on about a 6' mounting height in a room with 8' ceilings. Any advice? Thanks
Your two surround sound speakers should be located slightly behind from where you normally sit and at your ear level. When I sit, the center of my ears are at appprox 45" from floor level. The center of my surrounds are also at 45" off the floor. This works well.
You should place them where they sound good to YOU.