I bought a Super Bass a long time ago and when searching for cabinets I found an ad for two old PAs with 12" Greenbacks. Without knowing much about cabinets I thought these looked good and got them. Put two Vintage 30s in one of them so it could handle the output of the amp and for years I was quite satisfied with using just that one cabinet. But now I feel I miss more solid low frequencies (no ****! I know...). Thing is though, I really like those cabinets. Both the look of them and that they're easy to carry and transport. I don't play with the same people all the time so they're mostly at home and then I put the amp and a cab in my car when going to rehearse or jam. What I'd need some help with is to get the most out of these cabinets. I've thought about putting a piece of wood at the back of a cabinet to make them closed instead open but I have no idea whether this will make any improvement or maybe even making it worse. Another idea is to just get another set of high wattage 12"-speakers and use both cabinets. Maybe that would give me the extra boost that I need instead of modifying the cabinets. The last option is to buy new cabs altogether, but I really like the ones I have. Is there anyway you think I could improve the sound by using what I already have?