Go here
https://www.parts-express.com/cat/mi...%5D&PortalID=1
I checked the 2.5x4" but there are others for you to look at..
They are for TV's flat screens so they are not that deep..
If you want to skip paying shipping,, hit your local recycle center that takes t.v.'s.. open up a few and grab the speakers..
price will be right.. free.. I have a set here from a 32" they are 2"x4" so two side by side would fill your place.. and be plenty loud enough..