[sdiy] recycled led volume bar

[Rude 66]

i've pulled the display bar out of an old cassette deck. it includes the
whole circuit board with driver chip, etc. (all sony stuff). i'd like to use
this in some future project as a volume indicator or something similar, but
i'm having a hard time getting it to react to incoming audio.
there are 4 input wires: l and r (which i assume are for the audio
left/right parts), 5v and 'e'. the display bar works when i put +5v to the
'5v' input, and hook the 'e' up to gnd. but that makes all the led's light
up, and giving it audio input doesn't do aynthing. putting a pot in the 5v
line does reduce the amount of led's lit, but even with a 1k pot there's
only like 3 different 'settings'.

i'm obviously doing something wrong here.. can anyone point me in the right
direction how to hook this up?

thanks!

r./