Where is the Subwoofer

I have a 1992 BMW 735i and need to know where the Subwoofer is located.

Thanks

To my knowledge, there is no factory subwoofer. www.bavauto.com sells plug and play subwoofer systems but they are not cheap, at least not to my money. The system amplifier is located in the trunk under the parcel shelf on the right side.

where is the parcel shelf. I can't locate this

The parcel shelf is just that shelf behind the back seat where you can put a small bag or something, just in front of the rear window. Maybe it has another name, I don't know. You see the top of the shelf from the back seat and the bottom of the shelf from the trunk. Speakers are mounted up under the parcel shelf as well.