If this parameter is NULL, any currently playing waveform sound is stopped.

也就是第一个参数设置为NULL，就可以停止播放了。

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To control the recording process Steady Recorder displays a sound waveform and its spectrum in real-time.

为了控制录制过程稳态记录显示声音波形及其在实时频谱。

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This added resistance causes the waveform frequency to drop, lowering the pitch of the sound you hear internally and creating a sort of feedback effect that stimulates the eardrum from both sides.

声波降调的可能性增加，并且随着鼓膜双次振动带来的反馈效应，音高也会随之降低。

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SoundCloud allows us to embed those sound files right on WhiteHouse.gov, and users on SoundCloud can leave time-specific comments right in the waveform (the visual representation of the sound file).

WHITEHOUSE: Hearing from the White House in a New Way