diff --git a/lib_com/options.h b/lib_com/options.h
index 499a45afcaccdbf438b8eba5bbfc75c275211997..b3fcfadada0586b45cf97805c59c9a4396fda464 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -98,7 +98,7 @@
 #define FIX_BASOP_2509_EVS_CONCEAL_UNINIT_MEM           /* FhG: BASOP 2509: st->hTcxCfg->psychParamsCurrent is not initialized */
 #define HARMONIZE_2499_CONFIGUREFDCNGDEC                /* FhG: basop issue 2499: harmonoize configureFdCngDec */
 #define FIX_BASOP_2530_IVAS_DECISION_MAT                /* VA: Fix ambiguous usage of extract_l() */
-
+#define HARMONIZE_2508_InitTransientDetection          /* FhG: harmonize GetAttackForTCXDecision derivates for evs/ivas  */
 
 /* #################### End BE switches ################################## */
 
diff --git a/lib_enc/init_enc_fx.c b/lib_enc/init_enc_fx.c
index a8315f55558aa9ebfa78fd07964e1f8314d41922..e47b7621f600edcb7e015104284d1027875515ef 100644
--- a/lib_enc/init_enc_fx.c
+++ b/lib_enc/init_enc_fx.c
@@ -1202,11 +1202,19 @@ ivas_error init_encoder_fx(
 
     IF( GT_16( st->element_mode, EVS_MONO ) )
     {
+#ifdef HARMONIZE_2508_InitTransientDetection
+        InitTransientDetection_fx( input_frame, 0, st->hTranDet, 1, 1 /* > EVS_MONO */ );
+#else
         InitTransientDetection_ivas_fx( input_frame, 0, st->hTranDet, 1 );
+#endif
     }
     ELSE
     {
+#ifdef HARMONIZE_2508_InitTransientDetection
+        InitTransientDetection_fx( input_frame, NS2SA_FX2( st->input_Fs, DELAY_FIR_RESAMPL_NS ), st->hTranDet, 0, EVS_MONO );
+#else
         InitTransientDetection_fx( input_frame, NS2SA_FX2( st->input_Fs, DELAY_FIR_RESAMPL_NS ), st->hTranDet );
+#endif
     }
 
     /*-----------------------------------------------------------------*
diff --git a/lib_enc/ivas_mct_enc_fx.c b/lib_enc/ivas_mct_enc_fx.c
index 3f70a806c404163bdd887aa9a227ea571b9fea15..6abae475fdb0a99c9f0ff3c2f6fca0e60f331cfe 100644
--- a/lib_enc/ivas_mct_enc_fx.c
+++ b/lib_enc/ivas_mct_enc_fx.c
@@ -1195,8 +1195,11 @@ static ivas_error ivas_mc_enc_reconfig_fx(
             {
                 return ( IVAS_ERROR( IVAS_ERR_FAILED_ALLOC, "Can not allocate memory for Transient Detection\n" ) );
             }
-
+#ifdef HARMONIZE_2508_InitTransientDetection
+            InitTransientDetection_fx( extract_l( Mult_32_16( st->input_Fs, INV_FRAME_PER_SEC_Q15 ) ), NS2SA_FX2( st->input_Fs, DELAY_FIR_RESAMPL_NS ), st->hTranDet, 0, st->element_mode );
+#else
             InitTransientDetection_ivas_fx( extract_l( Mult_32_16( st->input_Fs, INV_FRAME_PER_SEC_Q15 ) ), NS2SA_FX2( st->input_Fs, DELAY_FIR_RESAMPL_NS ), st->hTranDet, 0 );
+#endif
         }
 
         IF( st->hIGFEnc == NULL )
diff --git a/lib_enc/prot_fx_enc.h b/lib_enc/prot_fx_enc.h
index d5987061021a9e1c325279704c598954de0e8c1b..7e4353573af2cb6108f591dbf2cd517bcd0b1312 100644
--- a/lib_enc/prot_fx_enc.h
+++ b/lib_enc/prot_fx_enc.h
@@ -878,6 +878,14 @@ void calculate_hangover_attenuation_gain_fx(
  *        Don't include the delay of the MDCT overlap.
  * @param pTransientDetection Structure to be initialized. It contains all transient detectors to be used.
  */
+#ifdef HARMONIZE_2508_InitTransientDetection
+void InitTransientDetection_fx(
+    const Word16 nFrameLength,
+    const Word16 nTCXDelay,
+    TRAN_DET_HANDLE hTranDet,
+    const Word16 ext_mem_flag,
+    Word16 element_mode );
+#else
 void InitTransientDetection_fx(
     const Word16 nFrameLength,
     const Word16 nTCXDelay,
@@ -888,6 +896,7 @@ void InitTransientDetection_ivas_fx(
     const Word16 nTCXDelay,
     TRAN_DET_HANDLE hTranDet,
     const Word16 ext_mem_flag );
+#endif
 
 /** Runs transient detection.
  * Runs all transient detectors defined in pTransientDetection
diff --git a/lib_enc/stat_enc.h b/lib_enc/stat_enc.h
index 2ee4a05f2d81af410b846214b414a897731adbbb..62e49a5a3c7ba873f8236560ea704ed0ba760af1 100644
--- a/lib_enc/stat_enc.h
+++ b/lib_enc/stat_enc.h
@@ -160,7 +160,11 @@ typedef struct
 
 
 /* Attack detection function. */
+#ifdef HARMONIZE_2508_InitTransientDetection
+typedef void ( *TCheckSubblocksForAttack_fx )( Word32 const *pSubblockNrg, Word32 const *pAccSubblockNrg, Word16 nSubblocks, Word16 nPastSubblocks, Word16 attackRatioThreshold, Word16 *pbIsAttackPresent, Word16 *pAttackIndex, Word16 element_mode );
+#else
 typedef void ( *TCheckSubblocksForAttack_fx )( Word32 const *pSubblockNrg, Word32 const *pAccSubblockNrg, Word16 nSubblocks, Word16 nPastSubblocks, Word16 attackRatioThreshold, Word16 *pbIsAttackPresent, Word16 *pAttackIndex );
+#endif
 
 /* Transient detector. */
 typedef struct TransientDetector
diff --git a/lib_enc/transient_detection_fx.c b/lib_enc/transient_detection_fx.c
index f671b8d9eef275a7c27505c68bbdf9f21f422b5a..a413e8ac1ad691f8ae2bda7869cdf6916bff0faa 100644
--- a/lib_enc/transient_detection_fx.c
+++ b/lib_enc/transient_detection_fx.c
@@ -42,15 +42,21 @@
 /************************************************/
 
 static void InitDelayBuffer( const Word16 nFrameLength, const Word16 nDelay, DelayBuffer *pDelayBuffer );
+#ifdef HARMONIZE_2508_InitTransientDetection
+static void InitSubblockEnergies_fx( const Word16 nFrameLength, const Word16 nDelay, DelayBuffer *pDelayBuffer, SubblockEnergies *pSubblockEnergies, Word16 element_mode );
+static void InitTransientDetector_fx( SubblockEnergies *pSubblockEnergies, const Word16 nDelay, const Word16 nSubblocksToCheck, const TCheckSubblocksForAttack_fx pCheckSubblocksForAttack, const Word16 attackRatioThreshold, TransientDetector *pTransientDetector, Word16 element_mode );
+static void RunTransientDetector_fx( TransientDetector *pTransientDetector, Word16 element_mode );
+#else
 static void InitSubblockEnergies( const Word16 nFrameLength, const Word16 nDelay, DelayBuffer *pDelayBuffer, SubblockEnergies *pSubblockEnergies );
 static void InitSubblockEnergies_ivas_fx( const Word16 nFrameLength, const Word16 nDelay, DelayBuffer *pDelayBuffer, SubblockEnergies *pSubblockEnergies );
 static void InitTransientDetector_fx( SubblockEnergies *pSubblockEnergies, const Word16 nDelay, const Word16 nSubblocksToCheck, const TCheckSubblocksForAttack_fx pCheckSubblocksForAttack, const Word16 attackRatioThreshold, TransientDetector *pTransientDetector );
 static void InitTransientDetector_ivas_fx( SubblockEnergies *pSubblockEnergies, const Word16 nDelay, const Word16 nSubblocksToCheck, const TCheckSubblocksForAttack_fx pCheckSubblocksForAttack, const Word16 attackRatioThreshold, TransientDetector *pTransientDetector );
+static void RunTransientDetector_fx( TransientDetector *pTransientDetector );
+#endif
 static void UpdateDelayBuffer( Word16 const *input, const Word16 nSamplesAvailable, DelayBuffer *pDelayBuffer );
 static void HighPassFilter_fx( Word16 const *input, const Word16 length, Word16 *pFirState1, Word16 *pFirState2, Word16 *output );
 static void UpdateSubblockEnergies( Word16 const *input, const Word16 nSamplesAvailable, SubblockEnergies *pSubblockEnergies );
 static void CalculateSubblockEnergies( Word16 const *input, const Word16 nSamplesAvailable, SubblockEnergies *pSubblockEnergies );
-static void RunTransientDetector_fx( TransientDetector *pTransientDetector );
 static void CalculateSubblockEnergies_ivas_fx( Word16 const *input, const Word16 nSamplesAvailable, SubblockEnergies *pSubblockEnergies );
 static void UpdateSubblockEnergies_ivas_fx( Word16 const *input, const Word16 nSamplesAvailable, SubblockEnergies *pSubblockEnergies );
 
@@ -66,6 +72,7 @@ static void UpdateSubblockEnergies_ivas_fx( Word16 const *input, const Word16 nS
  * See TCheckSubblocksForAttack_fx FOR definition of parameters.
  * It is assumed that the delay of MDCT overlap was not taken into account, so that the last subblock corresponds to the newest input subblock.
  */
+#ifndef HARMONIZE_2508_InitTransientDetection
 static void GetAttackForTCXDecision(
     Word32 const *pSubblockNrg,
     Word32 const *pAccSubblockNrg,
@@ -146,9 +153,11 @@ static void GetAttackForTCXDecision(
 
     return;
 }
+#endif
 
 
 /* GetAttackForTCXDecision() version using 32-bit for energy change values */
+#ifndef HARMONIZE_2508_InitTransientDetection
 static void GetAttackForTCXDecision_ivas_fx(
     Word32 const *pSubblockNrg,
     Word32 const *pAccSubblockNrg,
@@ -157,11 +166,25 @@ static void GetAttackForTCXDecision_ivas_fx(
     Word16 attackRatioThreshold,
     Word16 *pbIsAttackPresent,
     Word16 *pAttackIndex )
+#else
+static void GetAttackForTCXDecision_fx(
+    Word32 const *pSubblockNrg,
+    Word32 const *pAccSubblockNrg,
+    Word16 nSubblocks,
+    Word16 nPastSubblocks,
+    Word16 attackRatioThreshold,
+    Word16 *pbIsAttackPresent,
+    Word16 *pAttackIndex,
+    Word16 element_mode )
+#endif
 {
     Word16 i;
     Word16 bIsAttackPresent, attackIndex;
     Word16 attackRatioThreshold_1_5;
     Word64 W_tmp1, W_tmp2, W_tmp3;
+#ifdef HARMONIZE_2508_InitTransientDetection
+    Word32 L_tmp1, L_tmp2, L_tmp3;
+#endif
 
     assert( nSubblocks >= NSUBBLOCKS );
     assert( nPastSubblocks >= 2 );
@@ -172,23 +195,53 @@ static void GetAttackForTCXDecision_ivas_fx(
     move16();
     move16();
     bIsAttackPresent = FALSE;
+#ifdef HARMONIZE_2508_InitTransientDetection
+    attackIndex = EQ_16( element_mode, EVS_MONO ) ? 0 : -1;
+#else
     attackIndex = -1;
+#endif
     /* Search for the last attack in the subblocks */
     IF( s_or( (Word16) GT_32( L_shr( pSubblockNrg[-1], ATTACKTHRESHOLD_E ), Mpy_32_16_1( pAccSubblockNrg[-1], attackRatioThreshold ) ),
               L_sub( L_shr( pSubblockNrg[-2], ATTACKTHRESHOLD_E ), Mpy_32_16_1( pAccSubblockNrg[-2], attackRatioThreshold ) ) > 0 ) )
     {
         move16();
         bIsAttackPresent = TRUE;
+#ifdef HARMONIZE_2508_InitTransientDetection
+        if ( GT_16( element_mode, EVS_MONO ) )
+        {
+            attackIndex = 0;
+            move16();
+        }
+#else
         attackIndex = 0;
         move16();
+
+#endif
     }
 
     FOR( i = 0; i < NSUBBLOCKS; i++ )
     {
+#ifdef HARMONIZE_2508_InitTransientDetection
+        Word16 condition;
+        IF( EQ_16( element_mode, EVS_MONO ) )
+        {
+            L_tmp2 = L_shr( pSubblockNrg[i], ATTACKTHRESHOLD_E );
+            L_tmp1 = Mpy_32_16_1( pAccSubblockNrg[i], attackRatioThreshold );
+            condition = (Word16) GT_32( L_tmp2, L_tmp1 );
+        }
+        ELSE
+        {
+            W_tmp2 = W_shr( W_mult_32_16( pAccSubblockNrg[i], attackRatioThreshold ), 1 );
+            W_tmp1 = W_shl( pSubblockNrg[i], ( 15 - ATTACKTHRESHOLD_E ) );
+            condition = (Word16) GT_64( W_tmp1, W_tmp2 );
+        }
+        IF( condition )
+#else
         W_tmp2 = W_shr( W_mult_32_16( pAccSubblockNrg[i], attackRatioThreshold ), 1 );
         W_tmp1 = W_shl( pSubblockNrg[i], ( 15 - ATTACKTHRESHOLD_E ) );
 
         IF( GT_64( W_tmp1, W_tmp2 ) )
+#endif
         {
             if ( i < 6 )
             {
@@ -200,23 +253,44 @@ static void GetAttackForTCXDecision_ivas_fx(
             {
                 move16();
                 attackIndex = i;
-                W_tmp2 = W_shr( W_mult_32_16( pAccSubblockNrg[i], attackRatioThreshold ), 1 );
-                W_tmp2 = W_add( W_tmp2, W_shr( W_tmp2, 3 ) ); // pAccSubblockNrg[i] * 1.125f
-                W_tmp1 = W_shl( pSubblockNrg[i], ( 15 - ATTACKTHRESHOLD_E ) );
-                if ( s_and( (Word16) LT_64( W_tmp1, W_tmp2 ), s_or( (Word16) EQ_16( i, 2 ), (Word16) EQ_16( i, 6 ) ) ) )
+#ifdef HARMONIZE_2508_InitTransientDetection
+                IF( GT_16( element_mode, EVS_MONO ) )
                 {
-                    attackIndex = add( attackIndex, 1 ); /* avoid minimum overlap to prevent clicks */
+#endif
+                    W_tmp2 = W_shr( W_mult_32_16( pAccSubblockNrg[i], attackRatioThreshold ), 1 );
+                    W_tmp2 = W_add( W_tmp2, W_shr( W_tmp2, 3 ) ); // pAccSubblockNrg[i] * 1.125f
+                    W_tmp1 = W_shl( pSubblockNrg[i], ( 15 - ATTACKTHRESHOLD_E ) );
+                    if ( s_and( (Word16) LT_64( W_tmp1, W_tmp2 ), s_or( (Word16) EQ_16( i, 2 ), (Word16) EQ_16( i, 6 ) ) ) )
+                    {
+                        attackIndex = add( attackIndex, 1 ); /* avoid minimum overlap to prevent clicks */
+                    }
+#ifdef HARMONIZE_2508_InitTransientDetection
                 }
+#endif
             }
         }
         ELSE /* no attack, but set index anyway in case of strong energy increase */
         {
-            W_tmp2 = W_shr( W_mult_32_16( pSubblockNrg[i - 1], attackRatioThreshold_1_5 ), 1 );
-            W_tmp1 = W_shl( pSubblockNrg[i], ( 15 - ( ATTACKTHRESHOLD_E + 1 ) ) );
-            W_tmp3 = W_shr( W_mult_32_16( pSubblockNrg[i - 2], attackRatioThreshold_1_5 ), 1 );
+#ifdef HARMONIZE_2508_InitTransientDetection
+            IF( EQ_16( element_mode, EVS_MONO ) )
+            {
+                L_tmp2 = Mpy_32_16_1( pSubblockNrg[i - 1], attackRatioThreshold_1_5 );
+                L_tmp1 = L_shr( pSubblockNrg[i], 1 + ATTACKTHRESHOLD_E );
+                L_tmp3 = Mpy_32_16_1( pSubblockNrg[i - 2], attackRatioThreshold_1_5 );
+                condition = s_and( ( (Word16) GT_32( L_tmp1, L_tmp2 ) ), ( L_sub( L_tmp1, L_tmp3 ) > 0 ) );
+            }
+            ELSE
+            {
+#endif
+                W_tmp2 = W_shr( W_mult_32_16( pSubblockNrg[i - 1], attackRatioThreshold_1_5 ), 1 );
+                W_tmp1 = W_shl( pSubblockNrg[i], ( 15 - ( ATTACKTHRESHOLD_E + 1 ) ) );
+                W_tmp3 = W_shr( W_mult_32_16( pSubblockNrg[i - 2], attackRatioThreshold_1_5 ), 1 );
+#ifdef HARMONIZE_2508_InitTransientDetection
+                condition = s_and( ( (Word16) GT_64( W_tmp1, W_tmp2 ) ), ( W_sub( W_tmp1, W_tmp3 ) > 0 ) );
+            }
 
-            IF( s_and( ( (Word16) GT_64( W_tmp1, W_tmp2 ) ),
-                       ( W_sub( W_tmp1, W_tmp3 ) > 0 ) ) )
+            IF( condition )
+#endif
             {
 
                 IF( s_and( (Word16) NE_16( attackIndex, 2 ), (Word16) NE_16( attackIndex, 6 ) ) )
@@ -224,16 +298,22 @@ static void GetAttackForTCXDecision_ivas_fx(
                     move16();
                     attackIndex = i;
 
-                    W_tmp2 = W_mult_32_16( pSubblockNrg[i - 1], attackRatioThreshold );
-                    W_tmp3 = W_mult_32_16( pSubblockNrg[i - 2], attackRatioThreshold );
-                    W_tmp1 = W_shl( pSubblockNrg[i], ( 15 - ATTACKTHRESHOLD_E ) );
-
-                    if ( s_and( (Word16) s_or( (Word16) LT_64( W_tmp1, W_tmp2 ), (Word16)
-                                                                                     LT_64( W_tmp1, W_tmp3 ) ),
-                                s_or( (Word16) EQ_16( i, 2 ), (Word16) EQ_16( i, 6 ) ) ) )
+#ifdef HARMONIZE_2508_InitTransientDetection
+                    IF( GT_32( element_mode, EVS_MONO ) )
                     {
-                        attackIndex = add( attackIndex, 1 ); /* avoid minimum overlap to prevent clicks */
+#endif
+                        W_tmp2 = W_mult_32_16( pSubblockNrg[i - 1], attackRatioThreshold );
+                        W_tmp3 = W_mult_32_16( pSubblockNrg[i - 2], attackRatioThreshold );
+                        W_tmp1 = W_shl( pSubblockNrg[i], ( 15 - ATTACKTHRESHOLD_E ) );
+
+                        if ( s_and( (Word16) s_or( (Word16) LT_64( W_tmp1, W_tmp2 ), (Word16) LT_64( W_tmp1, W_tmp3 ) ),
+                                    s_or( (Word16) EQ_16( i, 2 ), (Word16) EQ_16( i, 6 ) ) ) )
+                        {
+                            attackIndex = add( attackIndex, 1 ); /* avoid minimum overlap to prevent clicks */
+                        }
+#ifdef HARMONIZE_2508_InitTransientDetection
                     }
+#endif
                 }
             }
         }
@@ -259,6 +339,7 @@ static void GetAttackForTCXDecision_ivas_fx(
 }
 
 
+#ifndef HARMONIZE_2508_InitTransientDetection
 /** Initialize TCX transient detector.
  * See InitTransientDetector_fx for definition of parameters.
  */
@@ -271,6 +352,7 @@ static void InitTCXTransientDetector(
 
     return;
 }
+#endif
 
 
 /************************************************/
@@ -278,7 +360,7 @@ static void InitTCXTransientDetector(
 /*              Interface functions             */
 /*                                              */
 /************************************************/
-
+#ifndef HARMONIZE_2508_InitTransientDetection
 void InitTransientDetection_fx(
     const Word16 nFrameLength,
     const Word16 nTCXDelay,
@@ -299,27 +381,57 @@ void InitTransientDetection_fx(
 
     return;
 }
+#endif
 
-
+#ifdef HARMONIZE_2508_InitTransientDetection
+void InitTransientDetection_fx(
+    const Word16 nFrameLength,
+    const Word16 nTCXDelay,
+    TRAN_DET_HANDLE hTranDet,
+    const Word16 ext_mem_flag,
+    Word16 element_mode )
+#else
 void InitTransientDetection_ivas_fx(
     const Word16 nFrameLength,
     const Word16 nTCXDelay,
     TRAN_DET_HANDLE hTranDet,
     const Word16 ext_mem_flag )
+#endif
 {
     /* Init the delay buffer. */
     InitDelayBuffer( nFrameLength, nTCXDelay, &hTranDet->delayBuffer );
 
 
     /* Init a subblock energies buffer used for the TCX Short/Long decision. */
+#ifdef HARMONIZE_2508_InitTransientDetection
+    InitSubblockEnergies_fx( nFrameLength, nTCXDelay, &hTranDet->delayBuffer, &hTranDet->subblockEnergies, element_mode );
+#else
     InitSubblockEnergies_ivas_fx( nFrameLength, nTCXDelay, &hTranDet->delayBuffer, &hTranDet->subblockEnergies );
-
+#endif
 
     /* Init the TCX Short/Long transient detector. */
+#ifdef HARMONIZE_2508_InitTransientDetection
+    InitTransientDetector_fx( &hTranDet->subblockEnergies, nTCXDelay, NSUBBLOCKS, GetAttackForTCXDecision_fx, 17408 /*8.5f/(1<<ATTACKTHRESHOLD_E) Q15*/, &hTranDet->transientDetector, element_mode );
+#else
     InitTransientDetector_ivas_fx( &hTranDet->subblockEnergies, nTCXDelay, NSUBBLOCKS, GetAttackForTCXDecision_ivas_fx, 17408 /*8.5f/(1<<ATTACKTHRESHOLD_E) Q15*/, &hTranDet->transientDetector );
+#endif /*HARMONIZE_2508_InitTransientDetection*/
 
 
     /* We need two past subblocks for the TCX TD and NSUBBLOCKS+1 for the temporal flatness measure FOR the TCX LTP. */
+#ifdef HARMONIZE_2508_InitTransientDetection
+    IF( ext_mem_flag && GT_16( element_mode, EVS_MONO ) )
+    {
+        hTranDet->transientDetector.pSubblockEnergies->nDelay =
+            add( hTranDet->transientDetector.pSubblockEnergies->nDelay, add( ( NSUBBLOCKS + 1 ), ( NSUBBLOCKS_SHIFT + 1 ) ) );
+        move16();
+    }
+    ELSE
+    {
+        hTranDet->transientDetector.pSubblockEnergies->nDelay =
+            add( hTranDet->transientDetector.pSubblockEnergies->nDelay, NSUBBLOCKS + 1 );
+        move16();
+    }
+#else
     IF( ext_mem_flag )
     {
         hTranDet->transientDetector.pSubblockEnergies->nDelay =
@@ -332,6 +444,7 @@ void InitTransientDetection_ivas_fx(
             add( hTranDet->transientDetector.pSubblockEnergies->nDelay, NSUBBLOCKS + 1 );
         move16();
     }
+#endif
 
     return;
 }
@@ -607,7 +720,11 @@ void RunTransientDetection_fx(
     UpdateSubblockEnergies( filteredInput, nSamplesAvailable, pSubblockEnergies );
 
     /* Run transient detectors. */
+#ifdef HARMONIZE_2508_InitTransientDetection
+    RunTransientDetector_fx( pTransientDetector, EVS_MONO );
+#else
     RunTransientDetector_fx( pTransientDetector );
+#endif
 
     /* Update the delay buffer. */
     UpdateDelayBuffer( filteredInput, nSamplesAvailable, &hTranDet->delayBuffer );
@@ -678,7 +795,11 @@ void RunTransientDetection_ivas_fx(
     UpdateSubblockEnergies_ivas_fx( filteredInput_fx, length, pSubblockEnergies );
 
     /* Run transient detectors. */
+#ifdef HARMONIZE_2508_InitTransientDetection
+    RunTransientDetector_fx( pTransientDetector, 1 /*signal non-EVS*/ );
+#else
     RunTransientDetector_fx( pTransientDetector );
+#endif
 
     /* Update the delay buffer. */
     UpdateDelayBuffer( filteredInput_fx, length, &hTranDet->delayBuffer );
@@ -1064,7 +1185,7 @@ static void InitDelayBuffer(
     return;
 }
 
-
+#ifndef HARMONIZE_2508_InitTransientDetection
 static void InitSubblockEnergies(
     const Word16 nFrameLength,
     const Word16 nDelay,
@@ -1096,33 +1217,55 @@ static void InitSubblockEnergies(
 
     return;
 }
+#endif
 
 
+#ifdef HARMONIZE_2508_InitTransientDetection
+static void InitSubblockEnergies_fx(
+    const Word16 nFrameLength,
+    const Word16 nDelay,
+    DelayBuffer *pDelayBuffer,
+    SubblockEnergies *pSubblockEnergies,
+    Word16 element_mode )
+#else
 static void InitSubblockEnergies_ivas_fx(
     const Word16 nFrameLength,
     const Word16 nDelay,
     DelayBuffer *pDelayBuffer,
     SubblockEnergies *pSubblockEnergies )
+#endif
 {
-    Word16 const nMaxBuffSize = NSUBBLOCKS + MAX_TD_DELAY;
-    move16();
-
     assert( ( pDelayBuffer != NULL ) && ( pSubblockEnergies != NULL ) && ( pDelayBuffer->nSubblockSize * NSUBBLOCKS == nFrameLength ) && ( pDelayBuffer->nSubblockSize > 0 ) );
 
-    set32_fx( pSubblockEnergies->subblockNrg, 54 /* 107.37 in Q(-1) */, nMaxBuffSize );
-    set32_fx( pSubblockEnergies->accSubblockNrg, 54 /* 107.37 in Q(-1) */, nMaxBuffSize + 1 );
-    set32_fx( pSubblockEnergies->subblockNrgChange_32fx, ONE_IN_Q15, nMaxBuffSize );
-    set16_fx( pSubblockEnergies->subblockNrgChange_exp, 16, nMaxBuffSize );
-    IF( nDelay != 0 )
+    Word16 nMaxBuffSize;
+
+#ifdef HARMONIZE_2508_InitTransientDetection
+    IF( EQ_16( element_mode, EVS_MONO ) )
     {
-        pSubblockEnergies->nDelay = idiv1616( nDelay, pDelayBuffer->nSubblockSize );
+        nMaxBuffSize = sizeof( pSubblockEnergies->subblockNrg ) / sizeof( pSubblockEnergies->subblockNrg[0] );
         move16();
+
+        set32_fx( pSubblockEnergies->subblockNrg, MIN_BLOCK_ENERGY, nMaxBuffSize );
+        set32_fx( pSubblockEnergies->accSubblockNrg, MIN_BLOCK_ENERGY, nMaxBuffSize + 1 );
+        set16_fx( pSubblockEnergies->subblockNrgChange, 0x7fff, nMaxBuffSize );
     }
     ELSE
     {
-        pSubblockEnergies->nDelay = 0;
+#endif
+        nMaxBuffSize = NSUBBLOCKS + MAX_TD_DELAY;
+        move16();
+
+
+        set32_fx( pSubblockEnergies->subblockNrg, 54 /* 107.37 in Q(-1) */, nMaxBuffSize );
+        set32_fx( pSubblockEnergies->accSubblockNrg, 54 /* 107.37 in Q(-1) */, nMaxBuffSize + 1 );
+        set32_fx( pSubblockEnergies->subblockNrgChange_32fx, ONE_IN_Q15, nMaxBuffSize );
+        set16_fx( pSubblockEnergies->subblockNrgChange_exp, 16, nMaxBuffSize );
+        pSubblockEnergies->q_firState = 15;
         move16();
+#ifdef HARMONIZE_2508_InitTransientDetection
     }
+#endif
+    pSubblockEnergies->nDelay = idiv1616_1( nDelay, pDelayBuffer->nSubblockSize );
     assert( pSubblockEnergies->nDelay < nMaxBuffSize );
     pSubblockEnergies->nPartialDelay = nDelay % pDelayBuffer->nSubblockSize;
     move16();
@@ -1132,8 +1275,6 @@ static void InitSubblockEnergies_ivas_fx(
     move16();
     pSubblockEnergies->firState2 = 0;
     move16();
-    pSubblockEnergies->q_firState = 15;
-    move16();
 
     pSubblockEnergies->pDelayBuffer = pDelayBuffer;
     pDelayBuffer->nDelay = s_max( pDelayBuffer->nDelay, pSubblockEnergies->nPartialDelay );
@@ -1142,7 +1283,6 @@ static void InitSubblockEnergies_ivas_fx(
     return;
 }
 
-
 /** Init transient detector.
  * Fills TransientDetector structure with sensible content and enable it.
  * @param pSubblockEnergies Subblock energies used in this transient detector.
@@ -1153,6 +1293,7 @@ static void InitSubblockEnergies_ivas_fx(
  * @param attackRatioThreshold Attack ratio threshold with exponent ATTACKTHRESHOLD_E.
  * @param pTransientDetector Structure to be initialized.
  */
+#ifndef HARMONIZE_2508_InitTransientDetection
 static void InitTransientDetector_fx(
     SubblockEnergies *pSubblockEnergies,
     const Word16 nDelay,
@@ -1188,8 +1329,18 @@ static void InitTransientDetector_fx(
 
     return;
 }
+#endif
 
-
+#ifdef HARMONIZE_2508_InitTransientDetection
+static void InitTransientDetector_fx(
+    SubblockEnergies *pSubblockEnergies,
+    const Word16 nDelay,
+    const Word16 nSubblocksToCheck,
+    const TCheckSubblocksForAttack_fx pCheckSubblocksForAttack,
+    const Word16 attackRatioThreshold,
+    TransientDetector *pTransientDetector,
+    Word16 element_mode )
+#else
 static void InitTransientDetector_ivas_fx(
     SubblockEnergies *pSubblockEnergies,
     const Word16 nDelay,
@@ -1197,7 +1348,37 @@ static void InitTransientDetector_ivas_fx(
     const TCheckSubblocksForAttack_fx pCheckSubblocksForAttack,
     const Word16 attackRatioThreshold,
     TransientDetector *pTransientDetector )
+#endif
 {
+#ifdef HARMONIZE_2508_InitTransientDetection
+    Word16 nMaxBuffSize;
+    IF( EQ_16( element_mode, EVS_MONO ) )
+    {
+        nMaxBuffSize = sizeof( pSubblockEnergies->subblockNrg ) / sizeof( pSubblockEnergies->subblockNrg[0] );
+        move16();
+        assert( ( pSubblockEnergies != NULL ) && ( pSubblockEnergies->pDelayBuffer != NULL ) && ( pTransientDetector != NULL ) && ( pSubblockEnergies->pDelayBuffer->nSubblockSize != 0 ) );
+        pTransientDetector->pSubblockEnergies = pSubblockEnergies;
+        pTransientDetector->nDelay = ( nDelay - pSubblockEnergies->nPartialDelay ) / pSubblockEnergies->pDelayBuffer->nSubblockSize;
+    }
+    ELSE
+    {
+        nMaxBuffSize = NSUBBLOCKS + MAX_TD_DELAY;
+        move16();
+        assert( ( pSubblockEnergies != NULL ) && ( pSubblockEnergies->pDelayBuffer != NULL ) && ( pTransientDetector != NULL ) && ( pSubblockEnergies->pDelayBuffer->nSubblockSize != 0 ) );
+        pTransientDetector->pSubblockEnergies = pSubblockEnergies;
+        IF( sub( nDelay, pSubblockEnergies->nPartialDelay ) != 0 )
+        {
+            pTransientDetector->nDelay = idiv1616( sub( nDelay, pSubblockEnergies->nPartialDelay ), pSubblockEnergies->pDelayBuffer->nSubblockSize );
+            move16();
+        }
+        ELSE
+        {
+            pTransientDetector->nDelay = 0;
+            move16();
+        }
+    }
+
+#else
     const Word16 nMaxBuffSize = NSUBBLOCKS + MAX_TD_DELAY;
     move16();
 
@@ -1213,6 +1394,7 @@ static void InitTransientDetector_ivas_fx(
         pTransientDetector->nDelay = 0;
         move16();
     }
+#endif
     assert( nDelay == pTransientDetector->nDelay * pSubblockEnergies->pDelayBuffer->nSubblockSize + pSubblockEnergies->nPartialDelay );
     assert( pTransientDetector->nDelay < nMaxBuffSize );
     pSubblockEnergies->nDelay = s_max( pSubblockEnergies->nDelay, pTransientDetector->nDelay );
@@ -1229,9 +1411,17 @@ static void InitTransientDetector_ivas_fx(
     move16();
     pTransientDetector->attackIndex = -1;
     move16();
+#ifdef HARMONIZE_2508_InitTransientDetection
+    IF( GT_16( element_mode, EVS_MONO ) )
+    {
+        pTransientDetector->pSubblockEnergies->ramp_up_flag = 0x0;
+        move16();
+    }
+#else
     pTransientDetector->pSubblockEnergies->ramp_up_flag = 0x0;
     move16();
 
+#endif
     return;
 }
 
@@ -1277,9 +1467,14 @@ static void HighPassFilter_fx(
     return;
 }
 
-
+#ifdef HARMONIZE_2508_InitTransientDetection
+static void RunTransientDetector_fx(
+    TransientDetector *pTransientDetector,
+    Word16 element_mode )
+#else
 static void RunTransientDetector_fx(
     TransientDetector *pTransientDetector )
+#endif
 {
     Word16 const attackRatioThreshold = pTransientDetector->attackRatioThreshold;
     move16();
@@ -1294,10 +1489,17 @@ static void RunTransientDetector_fx(
     assert( ( pTransientDetector->CheckSubblocksForAttack_fx != NULL ) );
 
 #define WMC_TOOL_SKIP
+#ifdef HARMONIZE_2508_InitTransientDetection
+    pTransientDetector->CheckSubblocksForAttack_fx( pSubblockNrg, pAccSubblockNrg,
+                                                    NSUBBLOCKS + nDelay, nRelativeDelay,
+                                                    attackRatioThreshold,
+                                                    &pTransientDetector->bIsAttackPresent, &pTransientDetector->attackIndex, element_mode );
+#else
     pTransientDetector->CheckSubblocksForAttack_fx( pSubblockNrg, pAccSubblockNrg,
                                                     NSUBBLOCKS + nDelay, nRelativeDelay,
                                                     attackRatioThreshold,
                                                     &pTransientDetector->bIsAttackPresent, &pTransientDetector->attackIndex );
+#endif
 #undef WMC_TOOL_SKIP
 
     return;