I looked for for a case for my rectangular speakers, but I didn't found any models compatible with my speakers here in Thingverse. So I decided to create my own model.
Files Speaker1e3b8Inch_3W_01.stl and Speaker1e3b8Inch_3W_02.stl: For 1+3/8" X 2+1/2" Speakers.
Files Speaker3e1b2Inch_5W_01.st and Speaker3e1b2Inch_5W_02.stl: For 1/2" X 3+1/2" Speakers.