I have it in the car in the front doors glued (for 2 doors sedans 8 mats á 50x20 cm) and you can hear a significant difference when you alone against knocks from outside on the rear door and the front of the non-insulated insulated door ... The sound of the speakers has improved even noticeable. It now roars less, the tones appear clearer and kickbass the installed 16.5 cm bass / midrange pushes a bit more than before. For almost 20 (with shipping) I am absolutely satisfied and give a strong buy recommendation!
