Sedan Model

Disconnect the ground terminal from the battery sensor, and wait for at least 60 seconds before starting work. Ref. to BATTERY
Remove the trim panel assembly - rear shelf. Ref. to REMOVAL , Rear Shelf Trim.
Remove the speaker assembly - woofer.
1. Disconnect the connector.
2. Remove the bolts and remove the speaker assembly - woofer.
Fig 1: Identifying Woofer Speaker Assembly Bolts
Courtesy of SUBARU OF AMERICA, INC.