i've got a 1x12 lopo line closed classic cab. i have discovered that i need an open speaker cab, but i do not want to ruin the purpose of the cab i have. plus, i cannot afford to buy another (more transactions = loss of money). any recommendations on how i should cut a 12x12 (or another size) port in the rear of the cab and possibly making it convertible (allowing the piece to be reattached)? thanks for the help.