Traditional unbalanced cables use two lines to transmit the audio signal - a hot line which carries the signal and an earth line. This is all that is required to transmit audio and is common in short cables (where noise is less of a problem) and less professional applications.
Note: Internal componentry (in sound mixers etc) is also unbalanced.
MAONO is an innovative designer and manufacturer of Lavalier, Podcasting, Wireless, Shotgun, Recording microphones and accessories for Smartphone, Camera and PC, etc.