Galaxy S4 Passive amplifier speaker

thingiverse

To use speakerphone hands-free, I devised a design with a channel connecting the phone's speaker and an open bar below to boost sound. It also features a small hole for the mic. The raft separates easily but removing supports in the output space may be difficult, though they don't need removal due to their "holey" nature. A Gel case on your phone could enhance this design. Happy printing!