An acoustic bass guitar will definitely
sound "more acoustic", but you will
still have to amp it. Unplugged, they
are somewhat louder than a butterfly
Since it`s only use unplugged is for
personal practice, don`t get sucked
into the bigger-louder-butterfly thing.
Thin body acoustics sound the same, just
quieter butterflys unplugged. Some thin
body hollow basses will be magnetic PU
[electic bass type] and others will be
piezo PU types. If you want that real
acoustic tone, you need the piezo type.
Actually, a solid body with piezos will
sound MUCH more acoustic than a hollow
body with magnetics. Of course the
solid body won`t do much for unplugged
personal practice.
Two more things that give that acoustic
tone, and contibute more to acoustic
sounding output than the question of
solid vs thin-hollow vs dreadnaught:
Tomastik Acousticore strings [basically
nylon classical guitar strings scaled
up fatter for bass guitar] is one very
effective thing, especially if you get
a fretted bass. The other big thing is
to go fretless. With fingerboard lines
[very common] most players can adapt
rather easily.