diff --git a/demo/ac_sound_capture1/ac_sound_capture1.cpp b/demo/ac_sound_capture1/ac_sound_capture1.cpp
index b126aac..8367409 100644
--- a/demo/ac_sound_capture1/ac_sound_capture1.cpp
+++ b/demo/ac_sound_capture1/ac_sound_capture1.cpp
@@ -152,6 +152,10 @@ void wavWriteVoice(string filename, uint32_t sample_rate, uint16_t bits_per_samp
 
 void sound_capture_callback(int32_t* voicedata, uint32_t len) {
   printf("sound_capture_callback:%d\n", len);
+  for (size_t i = 0; i < len; i++) {
+    voicedata[i] = voicedata[i] - 420079616; //声望录音设备AC信号有一个直流偏移分量
+  }
+
   wavWriteVoice("record.wav", 96000, 32, 1, (char*)voicedata, len * sizeof(int32_t));
 }