Hi everyone. So I bought a Gallien Krueger Goldline 210 in 2008. One of the speakers broke and I have had a better cab since 2010. Now I want to get the cab working again just to get a bit more volume out of a PA system. What I am wondering is what is the cubic volume of the cab? Is it bad to use two different types of speaker in the same cabinet? I would prefer to only buy one new speaker.