diff --git a/lib_com/options.h b/lib_com/options.h
index be4d83b0519d523ecc2822c6db6cf2a292d7acd5..d53b7d6a30590f91df7352489242629fa278a15a 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -84,6 +84,7 @@
 #define FIX_BASOP_ASSERT_IN_TONAL_MDCT_PLC                   /* FhG: fix for issue 2165 - using saturating addition in tonal MDCT PLC function */
 #define OPT_2146_BASOP_UTIL_ADD_MANT32EXP                    /* Dlb: optimized version of BASOP_Util_Add_Mant32Exp() */
 
+#define FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE                /* FhG: Use dynamic Q factor for synth_fx and synthFB_fx to prevent overflow */
 /* ################### End FIXES switches ########################### */
 
 /* #################### Start BASOP porting switches ############################ */
diff --git a/lib_com/prot_fx.h b/lib_com/prot_fx.h
index 32b8a00ee5d5457391c29147ac2dbdce9bcbde59..85984d53d3fad418a929f2f4be27ce08936c17ee 100644
--- a/lib_com/prot_fx.h
+++ b/lib_com/prot_fx.h
@@ -9101,6 +9101,9 @@ void decoder_tcx_ivas_fx(
     Word16 Aind[],
     Word16 synth_fx[],
     Word16 synthFB_fx[],
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+    Word16 *synth_q,
+#endif
     const Word16 bfi,
     const Word16 frame_cnt,
     const Word16 sba_dirac_stereo_flag );
diff --git a/lib_dec/dec_tcx_fx.c b/lib_dec/dec_tcx_fx.c
index ee8273a7b1b169da8679322e3ec9942974edaadd..a8db9f9cc43b08f7499839611e2dac97a8589c12 100644
--- a/lib_dec/dec_tcx_fx.c
+++ b/lib_dec/dec_tcx_fx.c
@@ -3970,10 +3970,16 @@ void decoder_tcx_IGF_stereo_fx(
 void decoder_tcx_ivas_fx(
     Decoder_State *st,
     Word16 prm[],
-    Word16 A_fx[],       // Q: 14 - norm_s(A_fx[0])
-    Word16 Aind[],       // Q: 14 - norm_s(Aind[0])
+    Word16 A_fx[], // Q: 14 - norm_s(A_fx[0])
+    Word16 Aind[], // Q: 14 - norm_s(Aind[0])
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+    Word16 synth_fx[],
+    Word16 synthFB_fx[],
+    Word16 *synth_q,
+#else
     Word16 synth_fx[],   // Q_syn
     Word16 synthFB_fx[], // Q_syn
+#endif
     const Word16 bfi,
     const Word16 frame_cnt,
     const Word16 sba_dirac_stereo_flag )
@@ -4063,8 +4069,9 @@ void decoder_tcx_ivas_fx(
     move16();
     q_winFB = st->Q_syn;
     move16();
-
+#ifndef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
     assert( q_win == 0 );
+#endif
 
     Scale_sig( synth_fx, L_frame_glob, sub( q_win, st->Q_syn ) );        // Scaling to Q_syn
     Scale_sig( synthFB_fx, L_frameTCX_glob, sub( q_winFB, st->Q_syn ) ); // Scaling to Q_syn
@@ -4073,8 +4080,18 @@ void decoder_tcx_ivas_fx(
                           fUseTns, &synth_fx[0], &synthFB_fx[0], bfi, frame_cnt, sba_dirac_stereo_flag );
 
     /* Scaling up again */
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+    Word16 q_min = s_min( add( q_win, getScaleFactor16( synth_fx, L_frame_glob ) ),
+                          add( q_winFB, getScaleFactor16( synthFB_fx, L_frameTCX_glob ) ) );
+    q_min = s_min( q_min, st->Q_syn );
+    Scale_sig( synth_fx, L_frame_glob, sub( q_min, q_win ) );
+    Scale_sig( synthFB_fx, L_frameTCX_glob, sub( q_min, q_winFB ) );
+    *synth_q = q_min;
+#else
     Scale_sig( synth_fx, L_frame_glob, sub( st->Q_syn, q_win ) );
     Scale_sig( synthFB_fx, L_frameTCX_glob, sub( st->Q_syn, q_winFB ) );
+#endif
+
     // Scale_sig( st->hTcxDec->syn_Overl, L_FRAME32k / 2, 1 );
 
     Scale_sig( st->hTcxDec->old_syn_Overl, 320, ( -2 - st->hTcxDec->Q_old_syn_Overl ) ); // Scaling to Q-2
diff --git a/lib_dec/er_dec_tcx_fx.c b/lib_dec/er_dec_tcx_fx.c
index 7cb4f897b24cc393f5589f14aaf2d0530ee9de4c..2c197d23d2645f71fe02088996c11b3beef14b04 100644
--- a/lib_dec/er_dec_tcx_fx.c
+++ b/lib_dec/er_dec_tcx_fx.c
@@ -105,7 +105,11 @@ void con_tcx_fx(
     Word16 pre_emph_buf;
     Word16 hp_filt[L_FIR_FER2];
     Word16 alpha;
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+    Word16 tmp_deemph, gain, gainCNG, gain_inov, scf;
+#else
     Word16 tmp_deemph, gain, gainCNG, gain_inov;
+#endif
     Word16 *pt_exc, *pt1_exc;
     Word16 Tc, tmpSeed;
     Word16 fUseExtrapolatedPitch;
@@ -190,9 +194,16 @@ void con_tcx_fx(
     IF( ( EQ_16( st->nbLostCmpt, 1 ) ) || hTcxDec->tcxConceal_recalc_exc )
     {
         /* apply pre-emphasis to the signal */
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+        mem = shl( synth[( -( ( ( shr( L_frame, 1 ) + hTcxDec->pit_max_TCX ) + M + M ) ) - 1 )], st->Q_syn_factor ); /*Q0*/
+#else
         mem = synth[( -( ( ( ( L_frame / 2 ) + hTcxDec->pit_max_TCX ) + M + M ) ) - 1 )]; /*Q0*/
+#endif
         move16();
         Q_exc = E_UTIL_f_preemph3( &( synth[-( ( ( L_frame / 2 ) + hTcxDec->pit_max_TCX ) + 2 * M )] ), st->preemph_fac, add( add( shr( L_frame, 1 ), hTcxDec->pit_max_TCX ), shl( M, 1 ) ), &mem, 1 );
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+        Scale_sig( &( synth[-( ( shr( L_frame, 1 ) + hTcxDec->pit_max_TCX ) + 2 * M )] ), add( add( shr( L_frame, 1 ), hTcxDec->pit_max_TCX ), shl( M, 1 ) ), negate( st->Q_syn_factor ) ); /*Q0, Setting back to Q0, as the following calculations are implemented assuming synth is in Q0 */
+#endif
         st->Mode2_lp_gainc = L_deposit_l( 0 );
 
         st->Mode2_lp_gainp = get_gain2( synth - shl( L_subfr, 1 ), synth - add( shl( L_subfr, 1 ), Tc ), shl( L_subfr, 1 ) ); /*Q16*/
@@ -231,9 +242,16 @@ void con_tcx_fx(
     ELSE
     {
         /* apply pre-emphasis to the signal */
-        mem = synth[( -L_frame - 1 )]; /*Q0*/
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+        mem = shl( synth[( -L_frame - 1 )], st->Q_syn_factor ); /*Q0*/
+#else
+        mem = synth[( -L_frame - 1 )];                                                    /*Q0*/
+#endif
         move16();
         Q_exc = E_UTIL_f_preemph3( &( synth[-L_frame] ), st->preemph_fac, L_frame, &mem, 1 );
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+        Scale_sig( &synth[-L_frame], L_frame, negate( st->Q_syn_factor ) ); /*Q0, Setting back to Q0, as the following calculations are implemented assuming synth is in Q0 */
+#endif
         Copy( st->old_Aq_12_8_fx, A_local, M + 1 ); /*Q12*/
 
         offset = shr( L_frame, 1 );
@@ -766,9 +784,26 @@ void con_tcx_fx(
 
     syn = buf + M;             /*Q_syn*/
     Copy( synth - M, buf, M ); /*Q_syn*/
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+    IF( NE_32( st->element_mode, EVS_MONO ) ) // to keep evs bit-exactness
+    {
+        scf = norm_s( tmp_deemph );
+        new_Q = sub( Q_exc, 4 );
+        new_Q = s_max( new_Q, -1 );
+        new_Q = s_min( new_Q, scf );
+    }
+    ELSE
+    {
+        new_Q = sub( Q_exc, 3 );
+        new_Q = s_max( new_Q, -1 );
 
+        scf = 0;
+        move16();
+    }
+#else
     new_Q = sub( Q_exc, 3 );
     new_Q = s_max( new_Q, -1 );
+#endif
 
     tmp16 = s_min( new_Q, st->prev_Q_syn );
     st->prev_Q_syn = new_Q;
@@ -779,8 +814,24 @@ void con_tcx_fx(
     move16();
 
     Copy_Scale_sig( buf, mem_syn, M, exp_scale ); /*Q: tmp16*/
-
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+    IF( NE_32( st->element_mode, EVS_MONO ) ) // to keep evs bit-exactness
+    {
+        if ( GT_16( sub( Q_syn, st->Q_syn_factor ), scf ) )
+        {
+            Q_syn = add( scf, st->Q_syn_factor ); // so that (Q_syn - st->Q_syn_factor) = scf;
+        }
+        tmp_deemph = shl( tmp_deemph, sub( Q_syn, st->Q_syn_factor ) );
+    }
+    ELSE
+    {
+        tmp_deemph = shl_sat( tmp_deemph, Q_syn ); /*Q_syn*/
+    }
+    st->Q_syn_factor = 0;
+    move16();
+#else
     tmp_deemph = shl_sat( tmp_deemph, Q_syn ); /*Q_syn*/
+#endif
     st->Q_syn = Q_syn;
     move16();
 
diff --git a/lib_dec/ivas_core_dec_fx.c b/lib_dec/ivas_core_dec_fx.c
index f3020662b8c87fd826cc41db8c9b65487b673b13..1fd7cb0f321f0433359b5e141c513ee0cf3e72b2 100644
--- a/lib_dec/ivas_core_dec_fx.c
+++ b/lib_dec/ivas_core_dec_fx.c
@@ -522,6 +522,16 @@ ivas_error ivas_core_dec_fx(
                 Scale_sig( st->hFdCngDec->hFdCngCom->A_cng, add( M, 1 ), sub( norm_s( sub( st->hFdCngDec->hFdCngCom->A_cng[0], 1 ) ), 3 ) ); // Qx
             }
 
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+            IF( ( EQ_32( st->last_core, TCX_10_CORE ) || EQ_32( st->last_core, TCX_20_CORE ) ) ||                                                                                                                                   // st->Q_syn_factor is set in TCX mode; otherwise, it may be uninitialized
+                ( hCPE != NULL && ( GT_16( hCPE->element_mode, IVAS_CPE_DFT ) && EQ_16( hCPE->last_element_mode, IVAS_CPE_DFT ) && ( ( EQ_32( sts[0]->last_core, TCX_10_CORE ) || EQ_32( sts[0]->last_core, TCX_20_CORE ) ) ) ) ) ) // In this case, sts[1] gets its value from sts[0].
+            {
+                Scale_sig( st->old_exc_fx, L_EXC_MEM_DEC, negate( st->Q_syn_factor ) );
+                st->Q_syn = add( st->Q_syn, st->Q_syn_factor );
+            }
+            st->Q_syn_factor = 0;
+            move16();
+#endif
             IF( NE_32( ( error = acelp_core_dec_fx( st, output_16_fx[n], synth_16_fx[n], save_hb_synth_16_fx, bwe_exc_extended_fx[n], voice_factors_fx[n], old_syn_12k8_16k_fx_16, sharpFlag[n], pitch_buf_fx[n], &unbits[n], &sid_bw[n], hStereoTD, tdm_lsfQ_PCh_fx, use_cldfb_for_dft, last_element_mode, last_element_brate, flag_sec_CNA, nchan_out, hStereoCng, read_sid_info ) ), IVAS_ERR_OK ) )
             {
                 return error;
@@ -597,8 +607,11 @@ ivas_error ivas_core_dec_fx(
             }
 
             stereo_tcx_core_dec_fx( st, frameMode[n], output_16_fx[n], synth_16_fx[n], pitch_buf_fx[n], sba_dirac_stereo_flag, hStereoTD, last_element_mode, flag_sec_CNA, hStereoCng, nchan_out, ivas_format );
-
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+            Copy_Scale_sig_16_32_DEPREC( output_16_fx[n], output_32_fx[n], output_frame, sub( Q11, st->Q_syn_factor ) ); // Q11
+#else
             Copy_Scale_sig_16_32_DEPREC( output_16_fx[n], output_32_fx[n], output_frame, Q11 ); // Q11
+#endif
 
             IF( st->hTcxDec )
             {
@@ -622,6 +635,10 @@ ivas_error ivas_core_dec_fx(
             move16();
             Q_synth = 0;
             move16();
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+            st->Q_syn_factor = 0;
+            move16();
+#endif
 
             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 );
 
@@ -805,7 +822,11 @@ ivas_error ivas_core_dec_fx(
          *---------------------------------------------------------------------*/
 
         /*core_switching_post_dec*/
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+        Q_synth = add( sub( 15, e_sig[0] ), st->Q_syn_factor );
+#else
         Q_synth = sub( 15, e_sig[0] );
+#endif
 
         /*------------------fix-to-fix-end-----------------------*/
 
diff --git a/lib_dec/ivas_stereo_switching_dec_fx.c b/lib_dec/ivas_stereo_switching_dec_fx.c
index da6adcf338b516d34c97671912252022e0075d3e..76041da3972c25556d65eb30efb00b2fc0fc9bb1 100644
--- a/lib_dec/ivas_stereo_switching_dec_fx.c
+++ b/lib_dec/ivas_stereo_switching_dec_fx.c
@@ -1951,6 +1951,10 @@ void stereo_switching_dec(
         Copy( sts[0]->old_exc_fx, sts[1]->old_exc_fx, L_EXC_MEM_DEC ); /* Q_exc */
         sts[1]->Q_exc = sts[0]->Q_exc;
         move16();
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+        sts[1]->Q_syn_factor = sts[0]->Q_syn_factor;
+        move16();
+#endif
         sts[1]->Q_exc_cng = sts[0]->Q_exc_cng;
         move16();
         sts[1]->prev_Q_exc = sts[0]->prev_Q_exc;
diff --git a/lib_dec/ivas_tcx_core_dec_fx.c b/lib_dec/ivas_tcx_core_dec_fx.c
index b36aad0c187920f8cfcb38dd974b11b18415b28a..6ee4bfe1899b36e77e6d4878d8e367ee5d6aaacf 100644
--- a/lib_dec/ivas_tcx_core_dec_fx.c
+++ b/lib_dec/ivas_tcx_core_dec_fx.c
@@ -234,7 +234,9 @@ void stereo_tcx_core_dec_fx(
     Word16 *synth_fx;
     Word16 synth_bufFB_fx[OLD_SYNTH_SIZE_DEC + L_FRAME_PLUS + M];
     Word16 *synthFB_fx;
-
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+    Word16 synth_q[2];
+#endif
     Word32 psd_fx[L_FRAME16k];
     Word32 psd_part_fx[NPART_SHAPING];
     Word16 psd_part_e;
@@ -335,7 +337,13 @@ void stereo_tcx_core_dec_fx(
         st->core = GetPLCModeDecision_ivas_fx( st ); /* Q0 */
         move16();
     }
-
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+    IF( st->core != ACELP_CORE )
+    {
+        st->Q_syn_factor = 0;
+        move16();
+    }
+#endif
     /*--------------------------------------------------------------------------------*
      * LPC envelope decoding
      *--------------------------------------------------------------------------------*/
@@ -596,7 +604,13 @@ void stereo_tcx_core_dec_fx(
         }
 
         /* TCX decoder */
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+        decoder_tcx_ivas_fx( st, prm, Aq_fx, Aind, &synth_fx[0], &synthFB_fx[0], &synth_q[0], bfi, 0, sba_dirac_stereo_flag );
+        st->Q_syn_factor = sub( synth_q[0], st->Q_syn );
+        st->Q_syn = synth_q[0];
+#else
         decoder_tcx_ivas_fx( st, prm, Aq_fx, Aind, &synth_fx[0], &synthFB_fx[0], bfi, 0, sba_dirac_stereo_flag );
+#endif
     }
 
     /*--------------------------------------------------------------------------------*
@@ -625,8 +639,27 @@ void stereo_tcx_core_dec_fx(
             }
 
             /* TCX decoder */
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+            decoder_tcx_ivas_fx( st, prm, Aq_fx, Aind, &synth_fx[k * st->L_frame / 2], &synthFB_fx[k * ( hTcxDec->L_frameTCX / 2 )], &synth_q[k], bfi, k, sba_dirac_stereo_flag );
+        }
+
+        Word16 q_min, q_shift;
+
+        q_min = s_min( synth_q[0], synth_q[1] );
+        st->Q_syn_factor = sub( q_min, st->Q_syn );
+        st->Q_syn = q_min;
+
+        q_shift = sub( q_min, synth_q[0] );
+        scale_sig( &synth_fx[0], shr( st->L_frame, 1 ), q_shift );
+        scale_sig( &synthFB_fx[0], shr( hTcxDec->L_frameTCX, 1 ), q_shift );
+
+        q_shift = sub( q_min, synth_q[1] );
+        scale_sig( &synth_fx[shr( st->L_frame, 1 )], shr( st->L_frame, 1 ), q_shift );
+        scale_sig( &synthFB_fx[shr( hTcxDec->L_frameTCX, 1 )], shr( hTcxDec->L_frameTCX, 1 ), q_shift );
+#else
             decoder_tcx_ivas_fx( st, prm, Aq_fx, Aind, &synth_fx[k * st->L_frame / 2], &synthFB_fx[k * ( hTcxDec->L_frameTCX / 2 )], bfi, k, sba_dirac_stereo_flag );
         }
+#endif
     }
 
     /*--------------------------------------------------------------------------------*
@@ -670,10 +703,17 @@ void stereo_tcx_core_dec_fx(
 #endif
         IF( !bfi && st->hTonalMDCTConc != NULL )
         {
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+            TonalMDCTConceal_SaveTimeSignal_ivas_fx( st->hTonalMDCTConc, synthFB_fx, st->Q_syn, hTcxDec->L_frameTCX );
+#else
             TonalMDCTConceal_SaveTimeSignal_ivas_fx( st->hTonalMDCTConc, synthFB_fx, 0, hTcxDec->L_frameTCX );
+#endif
         }
-
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+        decoder_tcx_post_ivas_fx( st, synth_fx, synthFB_fx, st->Q_syn, Aq_fx, bfi, 0 );
+#else
         decoder_tcx_post_ivas_fx( st, synth_fx, synthFB_fx, 0, Aq_fx, bfi, 0 );
+#endif
 
         IF( EQ_16( st->core, TCX_20_CORE ) )
         {
diff --git a/lib_dec/stat_dec.h b/lib_dec/stat_dec.h
index 81951104e50e56c21b9ff1dd41da427e29760e3a..8a8d6b09398d2b46219b6a3f740db980b33a879b 100644
--- a/lib_dec/stat_dec.h
+++ b/lib_dec/stat_dec.h
@@ -1310,7 +1310,11 @@ typedef struct Decoder_State
     Word16 Q_syn;
     Word16 Q_syn2;
     Word16 Q_syn_cng;
+#ifdef FIX_1793_DEC_MC_TO_MONO_SCALING_ISSUE
+    Word16 Q_syn_factor; // This q_factor is used to avoid using fix Q0 for synth[] at the output of con_tcx_ivas_fx() and ivas_core_dec_fx(). For con_tcx_ivas_fx, it is used for two consecutive TCX concealment processes and It cannot be greater than 0.
+#else
     Word16 Q_syn_factor; // This q_factor is used to avoid using fixed Q0 for synth[] at the output of con_tcx_ivas_fx(). It is then used for two consecutive TCX concealment processes. It cannot be greater than 0.
+#endif
     Word16 prev_Q_syn;
     Word16 prev_Q_bwe_exc;