I recently switched to bass in a hard rock/punk band and am looking to buy a new bass. We play in a drop Db tuning (Db Ab Db Gb) and I'm not sure if a 5 string is plausible? I don't posses the mechanic understandings of the instrument itself to know it's capabilities.

What would be the suggested tuning for the 5th string if I decided to go that route? Would dropping the B string down to an Ab push the instrument outside of a playable range down there?? Would a low Ab sound like garbage through my rig (Hartke 3500 head, 4X10, 1X15)?? Is there another suggested note to tune the lowest string too?? Are there any other considerations I need to think of to switch to a 5 string?? Or in my case, would it be better to simply stick with a 4 string??

Any help anyone could offer would be GREATLY appreciated!!