My mains are Polk Monitor 50's and my center channel is the Polk T30. The 50's go down to 42 Hz, the center 55Hz. My surrounds are the T15's, they go down to 60 Hz. I have an open back wall in my home theater. I had them in opposite corners but it felt like I could localize one of them. I had them both up between the mains. It just made voices coming from the center channel deep. Maybe I'm looking for something that Polk can't give me.