MikeM wrote
Why not use a router to cut the holes?
Not everyone has a circle jig for their router, Mike ?
I do have a jig like that and I use it when putting a hifi driver in a baffle - you want to make sure it sits flush with the front of the baffle to avoid off-axis funny stuff and to avoid phase problems. In a guitar cab you don't give a sh!t about these things since a) there are no frequency filters that give phase effects between tweeter and woofer and b) the frequencies involved are not high enough to hear off-axis effects.
So, you will mount your driver the easiest way possible - from the back, allowing you to cut inaccurately and even (as Marshall seem to do) cut corners.
