Does anyone know what physics is behind the incredible sound that comes from the X Mini speakers ?? https://www.amazon.com/X-Mini-II-Capsule-Speaker-Black/dp/B001UEBN42 How are they able to produce such volume from so small a package [the size is midway between the size of a tennis ball and a golf ball] ?? They actually replace computer speakers that are 20x their size. It is amazing ! And it does this while retaining very reasonable fidelity when playing music. When was this technique or technology discovered ?