[Raleigh]

Some electric drills have an impact feature that doesn't need a hammer blow to twist the screw. I'd use one of those before trying the hammer-type impact driver.

I've used hammer-type impact drivers a lot, and I don't think I'd use one on a speaker. Unless the screw or nut is mounted on something very solid that won't be damaged by a hammer blow, you should think of them as a tool of last resort. When you hit the tool with a hammer, it drives down as well as twists, concentrating the downward force on a very small area. You should be sure that a downward blow (as with a punch) won't damage your work.

I have damaged things irreparably by using this sort of tool. They've also worked well when used in the right kind of situation.