diff --git a/lib_dec/ivas_lfe_plc_fx.c b/lib_dec/ivas_lfe_plc_fx.c
index eaaf1d2a3cab1f980581eb7e7cd58a6204169b92..2b6be58e0db487f43a58fc56dc660ab4fc73b5df 100644
--- a/lib_dec/ivas_lfe_plc_fx.c
+++ b/lib_dec/ivas_lfe_plc_fx.c
@@ -829,7 +829,9 @@ static void d_syn_filt_fx(
 {
     Word16 i, j;
     Word32 buf_fx[LFE_PLC_LPCORD + LFE_PLC_RECLEN]; /* temporary synthesis buffer */
-    Word32 s_fx, *yy_fx, temp;
+    Word32 *yy_fx, temp;
+    Word64 s_fx;
+    Word16 tmp;
     Word16 yy_q_fx[LFE_PLC_LPCORD + LFE_PLC_RECLEN], exp1, exp2, s_q_fx, temp_q;
 
     yy_fx = &buf_fx[0];
@@ -852,7 +854,7 @@ static void d_syn_filt_fx(
     FOR( i = 0; i < l; i++ )
     {
         s_fx = x_fx[i];
-        move32();
+        move64();
         s_q_fx = Q31;
         move16();
         FOR( j = 1; j <= m; j++ )
@@ -874,20 +876,23 @@ static void d_syn_filt_fx(
 
             IF( LT_16( s_q_fx, temp_q ) )
             {
-                s_fx = L_sub( s_fx, L_shr( temp, sub( temp_q, s_q_fx ) ) );
+                s_fx = W_sub( s_fx, L_shr( temp, sub( temp_q, s_q_fx ) ) );
             }
             ELSE
             {
-                s_fx = L_sub( L_shr( s_fx, sub( s_q_fx, temp_q ) ), temp );
+                s_fx = W_sub( W_shr( s_fx, sub( s_q_fx, temp_q ) ), temp );
                 s_q_fx = temp_q;
                 move16();
             }
         }
-        yy_fx[i] = s_fx;
+        tmp = W_norm( s_fx );
+        s_fx = W_shl( s_fx, tmp );
+        s_q_fx = add( s_q_fx, tmp );
+        yy_fx[i] = W_extract_h( s_fx );
         move32();
-        yy_q_fx[i] = s_q_fx;
+        yy_q_fx[i] = sub( s_q_fx, 32 );
         move16();
-        y_fx[i] = L_shr( s_fx, sub( s_q_fx, Q5 ) );
+        y_fx[i] = W_extract_l( W_shr( s_fx, sub( s_q_fx, Q5 ) ) );
         move32();
     }
     *y_q_fx = Q5;