94 90csq Wiring: rear speakers

[siegfried <sdoerrer@ix.netcom.com>]

Pulled apart rear door to find cause of left-rear speaker cutting in and
out - usually fixed by a good flat-handed punch.  Thought it might have
been a loose connection.

To my dismay, found that the rear door features what appears to be
amplified rear speakers. Is this what they call the Bose system?  The
speakers themselves are labelled as "Nokia" and consist of 5.25"-ish
woofer, a 1.5"-ish tweeter, and a circuit board (w/ transformer,
capacitor, et al..) unit neatly attached to the woofer 

Does anybody know anything about these speakers or wiring? I'm thinking
about upgrading.

There are five wires to each speaker: 1) a red, 2) a green or blue, 3)
brown w/ black stripe, 4) white, and 5) brown.  The red and white have 7
to 12 volts.

Please respond to me directly since I'm not on the list.

TIA, Siegfried