Both are 5W/Ch boxes.
The 950 uses the same audio amp IC that the JVC M70 does, only not in BTL mode (The 950 has a single IC, the M70 has two). I'm not sure about the amp IC in the 850.
The 850 makes more BOOM from 5W because of the larger woofs, kinda like the Rising 20/20.
The tweets on the 850 look like cones, the 950 has weird metal-dome tweeters. My 950 has NO shortage of treble.
