diff --git a/lib_com/cnst.h b/lib_com/cnst.h
index 7b359e2f40ff80ab3db4a1848c9f0e3a781f28d6..8c986b363abb499b01f02f4bfdd211ff980e635a 100644
--- a/lib_com/cnst.h
+++ b/lib_com/cnst.h
@@ -1532,7 +1532,10 @@ typedef enum _DCTTYPE
 #define TOD_NSPEC                           80                      /* number of spectral bins of the tonal detector */
 #define TOD_THR_MASS                        0.86f                   /* initial value for the adaptive threshold of the tonal detector */
 #define P2A_FACT                            0.9f                    /* long-term averaging factor for peak-to-average ratio */
-#define THR_P2A                             80.0f                   /* threshold to detect strongly peaky signals */
+#ifdef FIX_SP2A
+#define THR_P2A_HIGH                        95.0f                   /* higher threshold to detect strongly peaky signals at low bitrates*/
+#endif
+#define THR_P2A                             80.0f                   /* lower threshold to detect strongly peaky signals at higher bitrates */
 
 /*----------------------------------------------------------------------------------*
  * LD music post-filter constants
diff --git a/lib_com/options.h b/lib_com/options.h
index 10f0df15a20a4ed32653dc45df1c9c28974d2bf6..aecaf8747a1464a0df9d4328168d334a77aeb7ff 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -162,6 +162,7 @@
 #define FIX_406_IVAS_POSITION                           /* Eri: Issue 406: Unify IVAS_POSITION to use IVAS_VECTOR3 instead */
 #define REND_DEBUGGING_REVISION                         /* VA: encapsulate rendering debugging options with DEBUGGING */
 #define FIX_416_ISM_BR_SWITCHING                        /* FhG: add missing CLDFB reconfig to ISM BR switching */
+#define FIX_SP2A                                        /* VA: Issue 412: Adjust threshold for the S_p2a feature in the tonal detector */
 
 
 
diff --git a/lib_enc/speech_music_classif.c b/lib_enc/speech_music_classif.c
index cf8568e649db982127b0cd978a935d7f28b97b2f..80bd2d6d2a8cc8aeb9c7d334e13959d824c0736e 100644
--- a/lib_enc/speech_music_classif.c
+++ b/lib_enc/speech_music_classif.c
@@ -1828,6 +1828,9 @@ void ivas_smc_mode_selection(
     float ton;
     int16_t i;
     float S_p2a, S_max, S_ave;
+#ifdef FIX_SP2A
+    float thr_sp2a;
+#endif
 
     SP_MUS_CLAS_HANDLE hSpMusClas = st->hSpMusClas;
 
@@ -1858,8 +1861,23 @@ void ivas_smc_mode_selection(
     S_ave = sum_f( st->hSpMusClas->tod_lt_Bin_E, TOD_NSPEC ) / TOD_NSPEC;
     S_p2a = S_max - S_ave;
 
+#ifdef FIX_SP2A
+    if ( element_brate <= IVAS_16k4 )
+    {
+        thr_sp2a = THR_P2A_HIGH;
+    }
+    else
+    {
+        thr_sp2a = THR_P2A;
+    }
+#endif
+
     /* initial 3-way selection of coding modes (ACELP/GSC/TCX) */
+#ifdef FIX_SP2A
+    if ( relE > -10.0f && ( S_p2a > thr_sp2a || ton > hSpMusClas->tod_thr_lt ) )
+#else
     if ( relE > -10.0f && ( S_p2a > THR_P2A || ton > hSpMusClas->tod_thr_lt ) )
+#endif
     {
         /* select TCX to encode extremely peaky signals or strongly tonal signals */
         st->sp_aud_decision1 = 1;