speaker pods for your car?
just cut out your rings out of mdf, and make them so the speaker recess into them,(2 parts glued together) then round the edges on the outside make the shape up you want as a base then make a spacer block that hold the two apart at the right space and angle then stretch some material over it (something thin and not 100% cotton cause it will soak up to much resin) pull the material tight and get out all the wrinkles. then pile on the resin dnt be shy. then cur the ring out and fill the inside with some resin and talc mixed up to form a thick powder to strenghten the inside spread that around but dont make it to think cause it will be heavy as. then just sand the outside till its glass smooth