@Almita – Wow, my situation was the opposite. I wanted to practice my voice lessons for choir class and I was worried that my neighbors would complain. I own a duplex and my garage is right against theirs, so I didn't want to start a big deal over noise. They are always quiet and the neighborhood is peaceful too.
I almost got the acoustical foam panels, but my garage needed insulated anyway – so I went with the insulation. I'm not exactly a professional, but with enough self-help books – I can figure out anything. So I insulated and boarded over the whole garage! It only took me three days since it's a one car garage.
No noise complaints so far and I've had my friends come over to play background music, so I guess it works.