Where does an AUX cord plug in?

Audio devices with a compatible 3.5mm AUX output plug can be connected, like MP3 players, smartphones, and tablets. Insert one end of the AUX cable into the AUX input on the bottom of your speaker. Insert the other end of the AUX cable into the AUX output port on your audio device.

Are aux cables better?

An optical cable is higher quality. A 3.5mm cable cannot be used in a fiber optic input/output, and a fiber optic cable cannot be used in a 3.5mm input/output. They each require different cables and connectors. Optical cables provide less interference but are more expensive and less common than 3.5mm cables.