diff --git a/spisound.c b/spisound.c
index 8a61960..5a236bc 100644
--- a/spisound.c
+++ b/spisound.c
@@ -52,14 +52,12 @@ typedef struct {
 
 static audio_t multiplierX2(int32_t *voice, int32_t size) {
   static int32_t voicebuf[MAX_ONE_FRAME_VOICE_SIZE * 2];  // 50ms
-  if (size > MAX_ONE_FRAME_VOICE_SIZE) {
-    size = MAX_ONE_FRAME_VOICE_SIZE;
-  }
-
   for (size_t i = 0; i < size; i++) {
     voicebuf[i * 2] = voice[i];
     if (i + 1 < size) {
       voicebuf[i * 2 + 1] = (voice[i] + voice[i + 1]) / 2;
+    } else {
+      voicebuf[i * 2 + 1] = voice[i] + (voice[i] - voice[i - 1]);
     }
   }
   audio_t ret;
@@ -78,6 +76,8 @@ static audio_t multiplierX2_2(int32_t *voice, int32_t size) {
     voicebuf[i * 2] = voice[i];
     if (i + 1 < size) {
       voicebuf[i * 2 + 1] = (voice[i] + voice[i + 1]) / 2;
+    } else {
+      voicebuf[i * 2 + 1] = voice[i] + (voice[i] - voice[i - 1]);
     }
   }
   audio_t ret;
@@ -115,18 +115,33 @@ static int32_t filter(int32_t input, int32_t v1, int32_t v2, int32_t v3, int32_t
 }
 
 static bool filterVoice(int32_t *voice, int32_t size) {
-#if 0
+#if 1
   static int32_t vbuf[MAX_ONE_FRAME_VOICE_SIZE * 3];  // 50ms
   static int32_t vbufnum = 0;
   vbufnum++;
 
   memmove(vbuf, vbuf + size, 2 * size * sizeof(int32_t));
   memcpy(vbuf + 2 * size, voice, size * sizeof(int32_t));
+  // printf("size:%d\n", size);
 
   if (vbufnum < 3) {
     return false;
   }
+
+  int32_t *cachebegin = &vbuf[size];
+  for (int i = 0; i < size; i++) {
+    voice[i] = filter(*(cachebegin + i),      //
+                      *(cachebegin + i - 1),  //
+                      *(cachebegin + i - 2),  //
+                      *(cachebegin + i - 3),  //
+                      *(cachebegin + i + 1),  //
+                      *(cachebegin + i + 2),  //
+                      *(cachebegin + i + 3));
+    // voice[i] = *(cachebegin + i);
+  }
+  return true;
 #endif
+#if 0
   static int32_t vbuf[MAX_ONE_FRAME_VOICE_SIZE];  // 50ms
   memcpy(vbuf, voice, size * sizeof(int32_t));
 
@@ -137,6 +152,7 @@ static bool filterVoice(int32_t *voice, int32_t size) {
                       *(cachebegin + i + 3));
     // voice[i] = cachebegin[i];
   }
+#endif
   return true;
 }
 
@@ -232,12 +248,19 @@ static void readvoice() {
   ret = read(m_fd, voicebuf, rxdatabytesize);
   gpio_set_value(1);
 
+  static int count = 0;
+  count++;
+  if (count < 10) {
+    return;
+  }
+
   int32_t voiceframesize = 0;
   bool    ready          = filterVoice(voicebuf, rxdatabytesize / 4);
   if (ready) {
     audio_t v1 = multiplierX2(voicebuf, rxdatabytesize / 4);
     audio_t v2 = multiplierX2_2(v1.voice, v1.size);
     if (m_callback) m_callback(v2.voice, v2.size);
+    // if (m_callback) m_callback(voicebuf, rxdatabytesize / 4);
   }
 
   return;