The Simplism Hibiki Acoustic iPhone Case ($340) was made to enhance the acoustic properties of your iPhone. Each case was made by a Japanese craftsman. The white ash wood used on the cases is usually reserved for high-end musical instruments. And on the inside of the case, a special high-tech material “PULSHUT MU” prevents degration to the sound quality and cancels ambient noise from non-audio signal waves. There are also 3D-shaped supporting points that suppress vibration. So if you’re looking for a case to enhance your audios without the need for external speakers and batteries, take a look at the Hibiki Acoustic iPhone Case.