diff --git a/lib_com/options.h b/lib_com/options.h
index 2299ff1629d49800475b7ce07b33fdf623329dcc..af3166f5398bd140dab73a185741aba9ac80eb93 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -94,7 +94,7 @@
 #define FIX_2176_ASSERT_DEC_MAP_PARAMS_DIRAC2STEREO          /* FhG: Reduce hStereoDft->q_smooth_buf_fx by one to prevent overflow in the subframe_band_nrg[][] calculation */
 #define FIX_2015_PREMPH_SAT_ALT                              /* VA: saturation can happen during preemphasis filtering due to a too aggressive scaling factor, allows preemphis to get 1 more bit headroom */
 #define FIX_2178_FL_TO_FX_WITH_OBJ_EDIT_FILE_INTERFACE       /* Nokia: Fixes float  to fx conversion in decoder app with object edit file interface */
-
+#define FIX_1947_DEC_HIGH_MLD_FOR_STEREO2MONO                /* FhG: Make Q-factor of synth_16_fx and output_16_fx dynamic to prevent overflow in HQ_CORE mode */
 /* ################### End FIXES switches ########################### */
 
 /* #################### Start BASOP porting switches ############################ */
diff --git a/lib_dec/ivas_core_dec_fx.c b/lib_dec/ivas_core_dec_fx.c
index 1fd7cb0f321f0433359b5e141c513ee0cf3e72b2..ae955c5edb8e8abb653d57d33c6706d95c93ce28 100644
--- a/lib_dec/ivas_core_dec_fx.c
+++ b/lib_dec/ivas_core_dec_fx.c
@@ -643,8 +643,14 @@ ivas_error ivas_core_dec_fx(
             ivas_hq_core_dec_fx( st, synth_16_fx[n], &Q_synth, output_frame, NORMAL_HQ_CORE, core_switching_flag[n], output_16_fx[n], &Q_output );
 
             Copy_Scale_sig_16_32_DEPREC( output_16_fx[n], output_32_fx[n], L_FRAME48k, sub( Q11, Q_output ) ); // Q11
-            Scale_sig( synth_16_fx[n], output_frame, negate( Q_synth ) );                                      // Q0
-            Scale_sig( output_16_fx[n], L_FRAME48k, negate( Q_output ) );                                      // Q0
+#ifdef FIX_1947_DEC_HIGH_MLD_FOR_STEREO2MONO
+            st->Q_syn_factor = s_min( 0, s_min( Q_synth, Q_output ) );
+            Scale_sig( synth_16_fx[n], output_frame, sub( st->Q_syn_factor, Q_synth ) ); // st->Q_syn_factor
+            Scale_sig( output_16_fx[n], L_FRAME48k, sub( st->Q_syn_factor, Q_output ) ); // st->Q_syn_factor
+#else
+            Scale_sig( synth_16_fx[n], output_frame, negate( Q_synth ) );                       // Q0
+            Scale_sig( output_16_fx[n], L_FRAME48k, negate( Q_output ) );                       // Q0
+#endif
         }
 
         /*---------------------------------------------------------------------*