diff --git a/lib_com/fd_cng_com_fx.c b/lib_com/fd_cng_com_fx.c
index dd84969a91dba71c14cbcf49315a1022d47a4da2..f439bbe28c86a3761de3e62f58aa92ae8779e305 100644
--- a/lib_com/fd_cng_com_fx.c
+++ b/lib_com/fd_cng_com_fx.c
@@ -2510,7 +2510,7 @@ void SynthesisSTFT(
     {
         FOR( i = 0; i < len; i++ )
         {
-            olapBuffer[i] = extract_l( L_shr_r( fftBuffer[i], 31 - fftBufferExp ) );
+            olapBuffer[i] = round_fx_sat( L_shl_sat( fftBuffer[i], fftBufferExp - 15 ) );
             move16();
         }
     }
@@ -2518,11 +2518,9 @@ void SynthesisSTFT(
     {
         FOR( i = 0; i < len4; i++ )
         {
-            // olapBuffer[i + 1 * len4] = add_sat( olapBuffer[i + 1 * len4], mult_r( round_fx( L_shl( fftBuffer[i + 1 * len4], fftBufferExp - 15 ) ), olapWin[i].v.im ) );
-            olapBuffer[i + 1 * len4] = add_sat( olapBuffer[i + 1 * len4], mult_r( extract_l( L_shr_r( fftBuffer[i + 1 * len4], 31 - fftBufferExp ) ), olapWin[i].v.im ) );
+            olapBuffer[i + 1 * len4] = add_sat( olapBuffer[i + 1 * len4], mult_r( round_fx_sat( L_shl_sat( fftBuffer[i + 1 * len4], fftBufferExp - 15 ) ), olapWin[i].v.im ) );
             move16();
-            // olapBuffer[i + 2 * len4] = add_sat( olapBuffer[i + 2 * len4], mult_r( round_fx( L_shl( fftBuffer[i + 2 * len4], fftBufferExp - 15 ) ), olapWin[len4 - 1 - i].v.re ) );
-            olapBuffer[i + 2 * len4] = add_sat( olapBuffer[i + 2 * len4], mult_r( extract_l( L_shr_r( fftBuffer[i + 2 * len4], 31 - fftBufferExp ) ), olapWin[len4 - 1 - i].v.re ) );
+            olapBuffer[i + 2 * len4] = add_sat( olapBuffer[i + 2 * len4], mult_r( round_fx_sat( L_shl_sat( fftBuffer[i + 2 * len4], fftBufferExp - 15 ) ), olapWin[len4 - 1 - i].v.re ) );
             move16();
         }
         FOR( i = len3; i < len; i++ )
@@ -2533,9 +2531,9 @@ void SynthesisSTFT(
 
     FOR( i = 0; i < len4; i++ )
     {
-        olapBuffer[i + 5 * len4] = mult_r( extract_l( L_shr_r( fftBuffer[i + 5 * len4], 31 - fftBufferExp ) ), olapWin[i].v.re );
+        olapBuffer[i + 5 * len4] = mult_r( round_fx_sat( L_shl_sat( fftBuffer[i + 5 * len4], fftBufferExp - 15 ) ), olapWin[i].v.re );
         move16();
-        olapBuffer[i + 6 * len4] = mult_r( extract_l( L_shr_r( fftBuffer[i + 6 * len4], 31 - fftBufferExp ) ), olapWin[len4 - 1 - i].v.im );
+        olapBuffer[i + 6 * len4] = mult_r( round_fx_sat( L_shl_sat( fftBuffer[i + 6 * len4], fftBufferExp - 15 ) ), olapWin[len4 - 1 - i].v.im );
         move16();
     }