Looking for a recommendation on a nice sounding 4 inch driver using it 250hz to 6 or 7 Khz. I will be using 2-4 drivers per side, so multiple driver set up. I want to keep it reasonable as I am experimenting, thinking the NOS Theils (but they are $50) or some SBA cheaper or even a dayton driver. I think they will be between $30-50 each. Thanks.