Knock Knock, whos in there?

[SVX92-97]

Here is a strange occurance. When I get in and close the drivers door, I hear what sounds like a knock or thump coming from the right side dash area. Havent looked into it yet to figure out what it could be. This knock or thump may or may not be linked to a similar sound I hear when driving over bumps. Just installed both front struts with OEM last week, and same sound is still there, before and after the new strut installation. This is very annoying to say the least. My mechanic checked the front suspension completely and found nothing wrong, or so he said, I was with him when he checked. Any ideas what this could be. The knock is very pronounced when closing the drivers door. It appears that something is either loose or broken, and when you close the door opposite the knock it jumps and knock. Cant describe it any other way. Help!