It's really simple to add a 1 ohm resistor to the front of the tweeter circuit, and you can start with a few different cheap 10W resistors in different values (0.5, 1, 1.5 etc.) to find what works best for you, then once you settle on the value you like most, you can swap it out for a nicer quality resistor like the new Dayton wire-wound or Mills resistors.