The holes on the bottom of the iPhone 5 case and iPhone 5 SkateCase are identical in size to the holes on the iPhone 5. We notice no discernable difference between with case and without case in mic/speaker functionality.
Why are there only 4 rows of holes by the headphone jack instead of the 5 on the iPhone 5 itself? One row of holes will not fit on our case because we enlarged the headphone jack as much as we could to accomidate more plugs. There is simply not enough room remaining to fit those holes in.