Cutting 4 perfectly round holes in a 3/4 inch thick piece of mdf. Router with trammel attachment. It took longer for the layout and getting the tools out than cutting the holes. I did a shallow cut on the bottom side so I wouldn't cut into the plywood I had set up on my sawhorses, then flipped it over and did progressively deeper cuts. Speakers are Ted Weber Alnico 10" 16 ohm 30 Watt. The cabinet will be the size of a Super Reverb, minus the control panel height.