Sean,
It may be either some type of caulk or gasket that is stuck. Maybe the speaker was inserted when the finish was fresh. I would try a flexible knife such as a filet knife. With the blade laying flat to the cabinet use a sawing/rocking motion all around until you've freed the mounting flange. You may even be able to put masking tape on the cabinet to prevent visible damage.
Good luck.
It may be either some type of caulk or gasket that is stuck. Maybe the speaker was inserted when the finish was fresh. I would try a flexible knife such as a filet knife. With the blade laying flat to the cabinet use a sawing/rocking motion all around until you've freed the mounting flange. You may even be able to put masking tape on the cabinet to prevent visible damage.
Good luck.