I've noticed that different speaker manufacturers offer differnet types of surround speakers. I know that placement is key when choosing which type. But overall, which is more flexible and why? Dipole/bipole or direct radiating? I'm getting a bit overwhelmed with my reaearch. The speakers I like (Canton LEs) only have a direct radiating (although thin and wall mountable) to be used for the surounds. Any thouhts or education would be greatly appreciated. Thanks so much...