Hello. I got out my x240 sub, last used it like a week ago but it was in a box. When i play a certain song, when there is a kick it sounds like its bottoming, but im not sure. Other types of songs work well... Maybe someone could tell me whats going on? (sorry for bad quality, was filmed in messenger) https/www.youtube.com/watch?v=n6Hxqw26vjc&feature=youtu.be and it sounds fine right here (same if not higher volume) https/www.youtube.com/watch?v=PSRlUt8JUc0&feature=youtu.be