Glued up my kit 81 speaker cabinets and I had a very small gap on the back panel. I used glue and clamps and pulled it tight. After a few days I noticed a very small split on the back panel on the end of the board on the same side with the gap. The crack is actually in the mdf and not in the glued joint. It is not very wide and the box is still sealed, but should I just put some glue in the crack to help seal it? I never built a sealed speaker and was curious if there is alot of pressure pushing on the back panel when the speaker is in use? I am worried it could possibly crack some more.