If the mobile phone is not compatible with the headset, the plug is not inserted properly, or the plug socket is damaged, it will cause only accompaniment and no lead singer.

The interface standards for mobile phone headsets include OMTP standards and CTIA standards. Most international manufacturers use the CTIA standard, such as iPhone headsets in the United States, Hong Kong and other international markets, while domestic licensed products need to support the OMTP standard. The main difference between the two is that the functional definitions of the plug leads are different and cannot be used universally.

In addition, stereo sound has two channels. If the plug is not inserted properly or the plug socket is damaged, and there is no ground wire, the two channels will form a loop without ground, and the signals of the two channels will be connected in series. In this way, the phases of the two channels are opposite, and the vocals will cancel each other out. It sounds like there is no lead singer but only accompaniment, and the bass is weakened.