Most combo amps come with an open back cabinet for obvious reasons. one of those being heat. My home stereo speakers are old and have passive radiators and come from an era when acoustic suspension was considered the best. New systems usually have a subwoofer which is ported. I realize these are serving different needs from a guitar amp. But that's about all I know. I'm thinking of getting a speaker cabinet and would like some help besides manufacturer hype. I notice various speaker cabinets out there. Some are closed back. Some are open back, some are ported. What are the advantages and disadvantages of each?