diff --git a/lib_com/options.h b/lib_com/options.h
index f595af53409a22ca5fd443f75ce70784f90d851c..a66408dd600cf2afccb54b3020f14379141a0eff 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -166,7 +166,7 @@
 #define ISM_FB_16k4                                     /* VA: Issue: 579: change BW from SWB to FB in NxISM conditions to match the EVS codec */
 #define FIX_580_PARAMMC_ENER_BURSTS                     /* FhG: issue 580: energy bursts due to ILD holding when energy relations change too much */
 #define FIX_593_STL_INCLUDE                             /* FhG: Issue 593: correct include of stl.h in lib_enc/ivas_stereo_eclvq_enc.c */
-
+#define FIX_583_CLANG_TRANS_DET                         /* FhG: Issue 583: clang left shift on ramp_up_flag in transient detector */
 
 /* ################## End BE DEVELOPMENT switches ######################### */
 
diff --git a/lib_enc/stat_enc.h b/lib_enc/stat_enc.h
index 4a47761f9c49f7da8551edcaf925993bc6b2b7a0..2e7924f37169ae01820e8ff5d16f13ab85ad4179 100644
--- a/lib_enc/stat_enc.h
+++ b/lib_enc/stat_enc.h
@@ -124,7 +124,11 @@ typedef struct
     float firState1;
     float firState2;
 
+#ifdef FIX_583_CLANG_TRANS_DET
+    uint16_t ramp_up_flag; /* bit map flags to indicate a ramp up in beginning of TCX frame */
+#else
     int16_t ramp_up_flag; /* bit map flags to indicate a ramp up in beginning of TCX frame */
+#endif
 
 } SubblockEnergies;
 
diff --git a/lib_enc/transient_detection.c b/lib_enc/transient_detection.c
index 1f8b36819f22bfa028814c617b723c4f0760a872..3b345b733396d022a2eae591fef15730b7a09238 100644
--- a/lib_enc/transient_detection.c
+++ b/lib_enc/transient_detection.c
@@ -241,7 +241,11 @@ void RunTransientDetection(
     UpdateDelayBuffer( filteredInput, length, &hTranDet->delayBuffer );
 
     /* compute ramp up flag */
+#ifdef FIX_583_CLANG_TRANS_DET
+    pSubblockEnergies->ramp_up_flag = ( ( pSubblockEnergies->ramp_up_flag << 1 ) & 0x0003 );
+#else
     pSubblockEnergies->ramp_up_flag = pSubblockEnergies->ramp_up_flag << 1;
+#endif
     e0 = dotp( filteredInput + length / 2, filteredInput + length / 2, pSubblockEnergies->pDelayBuffer->nSubblockSize / 2 ) + 0.5f * MIN_BLOCK_ENERGY;
     e1 = pSubblockEnergies->subblockNrg[pSubblockEnergies->nDelay + 4] - e0;
     if ( e1 > e0 )