I heard that it is recommended that the back wall of a sub box not be parallel to to wall the sub is mounted on. Should the back wall be slanted. Is this true? If it is how much will it affect SQ and SPL?
unless you are building abox 11ft by11ft I wouldnt worry about it. the reason they say to sland a box is because it breaks up standing waves inside of an enclosure. Notes under 80htz are very long in length I believe an 80hrt tone is 11.something ft and they get longer and longer the lower they go. So if you are building a box 3ft x 2ft you can build the squarest box you have ever seen with out a worry.