yea, when i first got my 98 i thought there was a sub, but after looking for awhile and not finding one...i just figured the bose mid range speakers are just kickass

 

sorry no one has answered your question to your liking.

In actuality, there are indeed two 6.5" 'subs' (if you can call them that) that are behind the head rests of the rear seats. The rear door panels hold the two standard 5 1/4 speakers that maintain the rest of the sound back there. Those 'subs' are powered by a bose amp in the trunk and are basically more pain than their worth if you're thinking of replacing them. As it is, i would leave them and just be happy with your nice sound. The reason i say 'sub' with quotations is that while they do give off bass, they are not big enough to be considered subwoofers and give off real low range frequencies. They are made to power bass sounds though, its just that 6.5" isn't that good for those ranges. I took mine out and replaced with 6.5" 3-way speakers (eclipse) and disabled the door speakers and installed subs in the trunk. (i keep meaning to replace those rear door speakers but need one more amp to power them, head unit can only power 4 speakers safely).



peace,
Chris

 

I don't even have the bose system and the system is still kickass! I have 1 8" sub in the back i believe. Audi knows how to do their sound systems that's for sure!