AudioRecord录制pcm

我在Android1.5上面用AudioRecord录制pcm时，用AudioTrack播放出来的全是噪音，以下是源码，谁做过这方面的，帮我分析一下。

录制：
int minBuffSize = AudioRecord.getMinBufferSize(8000,
AudioFormat.CHANNEL_CONFIGURATION_MONO,AudioFormat.ENCODING_PCM_16BIT);
  AudioRecord mAudioRecorder = new AudioRecord(MediaRecorder.AudioSource.MIC, 8000,
          AudioFormat.CHANNEL_CONFIGURATION_MONO,
          AudioFormat.ENCODING_PCM_16BIT, minBuffSize*3);
  //开始录音
  mAudioRecorder.startRecording();

  byte[] mBuffer = new byte[minBuffSize*3];
  //从MIC获取音频数据到mBuffer中

  int len = mAudioRecorder.read(mBuffer, 0, 1200);

播放：
int iMinBufSize = AudioTrack.getMinBufferSize(8000, 
AudioFormat.CHANNEL_CONFIGURATION_STEREO,
            AudioFormat.ENCODING_PCM_16BIT);
AudioTrack audioTrack=new AudioTrack(AudioManager.STREAM_MUSIC, 8000,
AudioFormat.CHANNEL_CONFIGURATION_STEREO, AudioFormat.ENCODING_PCM_16BIT,
iMinBufSize, AudioTrack.MODE_STREAM) ;

audioTrack.play();
audioTrack.write(data, 0, data.length);