http://www.androidauthority.com/3-5mm-audio-usb-type-c-701507/这里说， typeC 接口输出的是数字信号。原来手机里的数字模拟转换器+滤波回路+放大器，现在归耳机端制造了。
因此好的耳机，会把这一套音频电路，集成在耳机里面～～后面直接推动耳机扬声器～～。音质会稍好过通过长长的耳机线，再推动喇叭。
因为这样的耳机，相当与把耳机线缩短了：减少了耳机线引起的噪声，也减少了导线对有用声音的衰减。
The digital-to-analog converter, filtering circuits, and headphone amplifier will then all be housed in the headset near the headphones. Moving this circuitry slightly closer to the final headphone output might help remove some noise that ’ s picked up by long headphone cables and will keep important audio circuitry further away from noisy processing and radio hardware found inside phones.
这样的改动也代表了未来一种的可能性。～～爱好玄学的土豪们，你们有福了～