Thats a good question, I use those speakers and i am not sure I made a card board cut out and use that as a templet but never measured it. I took a protractor and made 1/2 circles and cut out the cardboard till it dropped over. Good speakers though I am on my 4 years of use.
Most speakers have a template for the cut out perforated into the shipping box......... If you do not have the box you can go here Technical Support | Boss Audio Systems and downlaod the manual to your speakers.
