My principal bass is a vintage Hofner Verithin bass; it plays nicely unplugged, solo, but won't match up to anything more than a nylon guitar, played softly. Most hollow-bodied instruments are not really hollow, they have a centre block and hollow 'wings', that's all. The old Hofners, including the violin bass, the Verithin and the President basses, are truly hollow, but not loud at all.
Hope this helps.