You don't have to get yourself an external microphone as the built-in microphone get you to experience clear sound and echo-free audio effect.
你不须要让自己一外接式麦克风，作为内置麦克风，让您体验到清晰的声音和回声免费的音频效果。
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The free version includes most of the core features of Echo, including the ability to share comments on Twitter and Facebook, nested replies, moderation tools, and customization.
IntroductionIn the communication systems, echo and noise will seriously affect speech communication quality, such as IP telephone, videophone and hand-free digital cell phone systems etc.