The expedit subwoofer is probably the easiest loudspeaker project I have done so far.
We had an Ikea Expedit shelf in our living room for quite a while. After finally buying an AV-Receiver there was also some need for a subwoofer, but there barely was space for placing a huge box.
I made some calculations using the volume one Expedit compartement has and came up with a pretty simple recipe: take a Mivoc AW3000 and a subwoofer amplification module (im my case it was a Mivoc AM120) and put it into one of you Expedits compartments. It is only necessary to create the baffle and the back wall. So in the end I spent 2 hours and finally had my subwoofer.
How does it sound?
For my purpose it is loud enough, the bass is deep enough and clean enough. If you need more power to can use more then one Expedit compartment.
It could be possible to convert it into a bassreflex subwoofer, but I did not make any simulations for that. I guess another speaker chassis is necessary to do so. Besides that an H-frame dipole could be possible as well, but I have not clue how to simulate one. However there is an interesting article on audiocircle.com on that topic.