difference between sealed and ported box

My main question is what is the biggest differences between having a sealed box and having a ported box. How does it effect SQ and SPL. Basically I just would like to know the basic rundown and the pro's and con's of either. Any input id greatly appreciated.Shake it, Don't break it

Well to start it off, sealed boxes are generally easier to build, are more suited to sq and allow speakers to handle a bit more power than ported boxes. Ported boxes are often tuned to a certain frequency and this freq. is where the box is loudest, unlike a sealed box that is smoother and rolls off more evenly. Power handeling is decreased throughout, except for the tuned frequency. I have found that properly built ported boxes can sound good too.