I am curious, how will mounting rings help with the sound quality of the speaker? If I don't build a back to the speaker, won't the speaker still be open in the rear still? I was told that the mounting rings help the speaker sound better, I'm not sure why though.

 

If they're made out of plastic it's just gonna make everything rattle. The only mounting rings I ever used were to make a pair of 6.5"s fit into the 6.75"s in the back. Those things rattled so bad it was terrible. Make sure you use dynomat or a similar product to sound deaden everything.