diff --git a/apps/decoder.c b/apps/decoder.c
index f6b55ba00f5851cf9aa35d911047ba98f45b2059..ca5b010fb0ac5b4826e8899306565946493aa06f 100644
--- a/apps/decoder.c
+++ b/apps/decoder.c
@@ -39,6 +39,9 @@
 #include "evs_rtp_payload.h"
 #include "ism_file_writer.h"
 #include "ivas_rtp_file.h"
+#ifdef FIX_1452_DEFAULT_REVERB
+#include "ivas_cnst.h"
+#endif
 #include "jbm_file_writer.h"
 #include "hrtf_file_reader.h"
 #include "ls_custom_file_reader.h"
diff --git a/apps/renderer.c b/apps/renderer.c
index 491433d645a25ba2da700da30c92c9187391f336..0d313f9a94df449768e3785666edfbeb414a722c 100644
--- a/apps/renderer.c
+++ b/apps/renderer.c
@@ -50,6 +50,9 @@
 #include "split_render_file_read_write.h"
 #include "split_rend_bfi_file_reader.h"
 #include "vector3_pair_file_reader.h"
+#ifdef FIX_1452_DEFAULT_REVERB
+#include "ivas_cnst.h"
+#endif
 #ifdef DEBUGGING
 #include "debug.h"
 #endif
@@ -1087,6 +1090,53 @@ int main(
         fprintf( stderr, "\nError in Renderer Config Init: %s\n", ivas_error_to_string( error ) );
         goto cleanup;
     }
+#ifdef FIX_1452_DEFAULT_REVERB
+
+    if ( args.outConfig.audioConfig == IVAS_AUDIO_CONFIG_BINAURAL_ROOM_REVERB )
+    {
+        /* Set reverb room size if specified or select based automatically based on default per input formats */
+        IVAS_ROOM_SIZE_T selectedReverbRoomSize = args.reverbRoomSize;
+        if ( selectedReverbRoomSize == IVAS_ROOM_SIZE_AUTO )
+        {
+            bool combinedFormat = false;
+            selectedReverbRoomSize = IVAS_ROOM_SIZE_MEDIUM;
+
+            /* ISM present with MASA/SBA inputs; treat as combined format */
+            if ( args.inConfig.numAudioObjects > 0 && ( args.inConfig.numMasaBuses > 0 || args.inConfig.numAmbisonicsBuses > 0 ) )
+            {
+                combinedFormat = true;
+            }
+
+            if ( combinedFormat )
+            {
+                selectedReverbRoomSize = IVAS_ROOM_SIZE_MEDIUM;
+            }
+            else
+            {
+                /* Only set large if ISM is present alone, MASA and Ambisonic have been checked above */
+                if ( args.inConfig.numAudioObjects > 0 && args.inConfig.numMultiChannelBuses == 0 )
+                {
+                    selectedReverbRoomSize = IVAS_ROOM_SIZE_LARGE;
+                }
+                /* if only MC is present, set medium; Will not be overridden by the subsequent block */
+                else if ( args.inConfig.numMultiChannelBuses > 0 )
+                {
+                    selectedReverbRoomSize = IVAS_ROOM_SIZE_MEDIUM;
+                }
+                else if ( args.inConfig.numMasaBuses > 0 || args.inConfig.numAmbisonicsBuses > 0 )
+                {
+                    selectedReverbRoomSize = IVAS_ROOM_SIZE_SMALL;
+                }
+            }
+        }
+
+        if ( ( IVAS_REND_SetReverbRoomSize( hIvasRend, selectedReverbRoomSize ) ) != IVAS_ERR_OK )
+        {
+            fprintf( stderr, "\nError setting reverb room size\n" );
+            goto cleanup;
+        }
+    }
+#endif
 
     if ( args.renderConfigFilePath[0] != '\0' )
     {
diff --git a/lib_com/common_api_types.h b/lib_com/common_api_types.h
index ab9ae0ad3343a61714792a70eadcbc9b71ec7131..a0e420c3660dcb457d57efbea8bca4cdd4a3f55e 100644
--- a/lib_com/common_api_types.h
+++ b/lib_com/common_api_types.h
@@ -60,7 +60,9 @@
 #define IVAS_ROOM_ABS_COEFF              6
 #define IVAS_REVERB_PREDELAY_MAX         20 /* Max input delay for reverb module */
 #define IVAS_ER_LIST_HEIGHT              1.6f
-#define IVAS_DEFAULT_AEID                65535
+#ifndef FIX_1452_DEFAULT_REVERB
+#define IVAS_DEFAULT_AEID 65535
+#endif
 
 /* JBM constants for adaptive-playout */
 #define IVAS_TIME_SCALE_MIN 50  /* min. time-scaling [%] */
diff --git a/lib_com/ivas_cnst.h b/lib_com/ivas_cnst.h
index 609fb930aca67722e39b8bcacf6bb9eaf46c0aff..05f5ea29d9639c7aafd56f5304706aeec31e60a6 100644
--- a/lib_com/ivas_cnst.h
+++ b/lib_com/ivas_cnst.h
@@ -1593,6 +1593,14 @@ typedef enum
 #define IVAS_REVERB_DEFAULT_M_N_BANDS           31
 #define IVAS_REVERB_DEFAULT_S_N_BANDS           60
 
+#ifdef FIX_1452_DEFAULT_REVERB
+#define IVAS_REVERB_DEFAULT_SYNTH_PRE_DELAY     0.016f
+#define IVAS_REVERB_DEFAULT_S_INPUT_PRE_DELAY   0.0f
+#define IVAS_REVERB_DEFAULT_M_INPUT_PRE_DELAY   0.0f
+#define IVAS_REVERB_DEFAULT_L_INPUT_PRE_DELAY   0.1f
+#define IVAS_DEFAULT_AEID                       65535u
+#endif
+
 #define LR_IAC_LENGTH_NR_FC                     ( RV_LENGTH_NR_FC )
 #define LR_IAC_LENGTH_NR_FC_16KHZ               ( RV_LENGTH_NR_FC_16KHZ )
 
diff --git a/lib_com/options.h b/lib_com/options.h
index 3bc10a191e06cedf885474468f31482908e30b1f..a2228d24c247cac7e28eb5dcad1f81d6c09e4018 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -172,6 +172,7 @@
 
 
 #define FIX_1435_MOVE_STEREO_PANNING                    /* VA: issue 1435: do the EVS stereo panning in the renderer */
+#define FIX_1452_DEFAULT_REVERB                  /* Philips/Nokia: Default room sizes support */
 #define FIX_1454_FIX_STEREO_TO_FOA_JBM                  /* VA: issue 1454: fix buggy stereo to FOA in JBM */
 #define FIX_1461_CNG_BW_SWITCHING                       /* Eri: issue 1461: Stereo parameters are not updated when SID/NODATA forces BW to stay the same */
 
diff --git a/lib_rend/ivas_render_config.c b/lib_rend/ivas_render_config.c
index f4348b2cf062ddd000da7340661d5d496e6a00f5..e01478caa9e9988e843f3a2354efc869d9119786 100644
--- a/lib_rend/ivas_render_config.c
+++ b/lib_rend/ivas_render_config.c
@@ -35,6 +35,9 @@
 #include "prot.h"
 #include "ivas_prot_rend.h"
 #include "ivas_rom_rend.h"
+#ifdef FIX_1452_DEFAULT_REVERB
+#include "ivas_cnst.h"
+#endif
 #ifdef DEBUGGING
 #include "debug.h"
 #endif
@@ -45,6 +48,7 @@
  * Local constants
  *-----------------------------------------------------------------------*/
 
+#ifndef FIX_1452_DEFAULT_REVERB
 #define IVAS_REVERB_DEFAULT_L_PRE_DELAY   0.016f
 #define IVAS_REVERB_DEFAULT_L_INPUT_DELAY 0.1f
 
@@ -53,6 +57,7 @@
 
 #define IVAS_REVERB_DEFAULT_M_PRE_DELAY   0.0125f
 #define IVAS_REVERB_DEFAULT_M_INPUT_DELAY 0.0f
+#endif
 
 #define IVAS_REVERB_DEFAULT_USE_ER 0
 
@@ -118,8 +123,13 @@ ivas_error ivas_render_config_init_from_rom(
 
     ( *hRenderConfig )->roomAcoustics.aeID = IVAS_DEFAULT_AEID;
     ( *hRenderConfig )->roomAcoustics.nBands = IVAS_REVERB_DEFAULT_L_N_BANDS;
+#ifdef FIX_1452_DEFAULT_REVERB
+    ( *hRenderConfig )->roomAcoustics.acousticPreDelay = IVAS_REVERB_DEFAULT_SYNTH_PRE_DELAY;
+    ( *hRenderConfig )->roomAcoustics.inputPreDelay = IVAS_REVERB_DEFAULT_L_INPUT_PRE_DELAY;
+#else
     ( *hRenderConfig )->roomAcoustics.acousticPreDelay = IVAS_REVERB_DEFAULT_L_PRE_DELAY;
     ( *hRenderConfig )->roomAcoustics.inputPreDelay = IVAS_REVERB_DEFAULT_L_INPUT_DELAY;
+#endif
     ( *hRenderConfig )->roomAcoustics.use_er = IVAS_REVERB_DEFAULT_USE_ER;
     set_zero( &( *hRenderConfig )->roomAcoustics.pFc_input[0], CLDFB_NO_CHANNELS_MAX );
     set_zero( &( *hRenderConfig )->roomAcoustics.pAcoustic_rt60[0], CLDFB_NO_CHANNELS_MAX );
@@ -167,13 +177,14 @@ ivas_error ivas_render_config_change_defaults(
     IVAS_DefaultReverbSize defaultReverbSize /* i:   Reverb default size    */
 )
 {
+    hRenderConfig->roomAcoustics.acousticPreDelay = IVAS_REVERB_DEFAULT_SYNTH_PRE_DELAY;
+    hRenderConfig->roomAcoustics.use_er = IVAS_REVERB_DEFAULT_USE_ER;
+
     switch ( defaultReverbSize )
     {
         case DEFAULT_REVERB_SMALL:
             hRenderConfig->roomAcoustics.nBands = IVAS_REVERB_DEFAULT_S_N_BANDS;
-            hRenderConfig->roomAcoustics.acousticPreDelay = IVAS_REVERB_DEFAULT_S_PRE_DELAY;
-            hRenderConfig->roomAcoustics.inputPreDelay = IVAS_REVERB_DEFAULT_S_INPUT_DELAY;
-            hRenderConfig->roomAcoustics.use_er = IVAS_REVERB_DEFAULT_USE_ER;
+            hRenderConfig->roomAcoustics.inputPreDelay = IVAS_REVERB_DEFAULT_S_INPUT_PRE_DELAY;
             set_zero( &hRenderConfig->roomAcoustics.pFc_input[0], CLDFB_NO_CHANNELS_MAX );
             set_zero( &hRenderConfig->roomAcoustics.pAcoustic_rt60[0], CLDFB_NO_CHANNELS_MAX );
             set_zero( &hRenderConfig->roomAcoustics.pAcoustic_dsr[0], CLDFB_NO_CHANNELS_MAX );
@@ -184,9 +195,7 @@ ivas_error ivas_render_config_change_defaults(
             break;
         case DEFAULT_REVERB_MEDIUM:
             hRenderConfig->roomAcoustics.nBands = IVAS_REVERB_DEFAULT_M_N_BANDS;
-            hRenderConfig->roomAcoustics.acousticPreDelay = IVAS_REVERB_DEFAULT_M_PRE_DELAY;
-            hRenderConfig->roomAcoustics.inputPreDelay = IVAS_REVERB_DEFAULT_M_INPUT_DELAY;
-            hRenderConfig->roomAcoustics.use_er = IVAS_REVERB_DEFAULT_USE_ER;
+            hRenderConfig->roomAcoustics.inputPreDelay = IVAS_REVERB_DEFAULT_M_INPUT_PRE_DELAY;
             set_zero( &hRenderConfig->roomAcoustics.pFc_input[0], CLDFB_NO_CHANNELS_MAX );
             set_zero( &hRenderConfig->roomAcoustics.pAcoustic_rt60[0], CLDFB_NO_CHANNELS_MAX );
             set_zero( &hRenderConfig->roomAcoustics.pAcoustic_dsr[0], CLDFB_NO_CHANNELS_MAX );
@@ -197,9 +206,7 @@ ivas_error ivas_render_config_change_defaults(
             break;
         case DEFAULT_REVERB_LARGE:
             hRenderConfig->roomAcoustics.nBands = IVAS_REVERB_DEFAULT_L_N_BANDS;
-            hRenderConfig->roomAcoustics.acousticPreDelay = IVAS_REVERB_DEFAULT_L_PRE_DELAY;
-            hRenderConfig->roomAcoustics.inputPreDelay = IVAS_REVERB_DEFAULT_L_INPUT_DELAY;
-            hRenderConfig->roomAcoustics.use_er = IVAS_REVERB_DEFAULT_USE_ER;
+            hRenderConfig->roomAcoustics.inputPreDelay = IVAS_REVERB_DEFAULT_L_INPUT_PRE_DELAY;
             set_zero( &hRenderConfig->roomAcoustics.pFc_input[0], CLDFB_NO_CHANNELS_MAX );
             set_zero( &hRenderConfig->roomAcoustics.pAcoustic_rt60[0], CLDFB_NO_CHANNELS_MAX );
             set_zero( &hRenderConfig->roomAcoustics.pAcoustic_dsr[0], CLDFB_NO_CHANNELS_MAX );
diff --git a/lib_rend/lib_rend.c b/lib_rend/lib_rend.c
index 9462886b3f5cb2f9ef8b63108d43f4eb17cdf841..aa3bd412aa69fccd91269e18877aecb55df66794 100644
--- a/lib_rend/lib_rend.c
+++ b/lib_rend/lib_rend.c
@@ -4663,6 +4663,9 @@ ivas_error IVAS_REND_FeedRenderConfig(
     hRenderConfig = hIvasRend->hRendererConfig;
 
     hRenderConfig->roomAcoustics.aeID = renderConfig.roomAcoustics.aeID;
+#ifdef FIX_1452_DEFAULT_REVERB
+    hIvasRend->selectedRoomReverbSize = DEFAULT_REVERB_UNSET;
+#endif
     hRenderConfig->roomAcoustics.nBands = renderConfig.roomAcoustics.nBands;
     hRenderConfig->roomAcoustics.acousticPreDelay = renderConfig.roomAcoustics.acousticPreDelay;
     hRenderConfig->roomAcoustics.inputPreDelay = renderConfig.roomAcoustics.inputPreDelay;
@@ -5249,8 +5252,7 @@ ivas_error IVAS_REND_SetReverbRoomSize(
             break;
         case IVAS_ROOM_SIZE_AUTO:
         default:
-            hIvasRend->selectedRoomReverbSize = DEFAULT_REVERB_UNSET;
-            break; /* will be setup in IVAS_REND_AddInput() */
+            assert( 0 && "Room size is not set" );
     }
 
     if ( hIvasRend->hRendererConfig != NULL )
diff --git a/lib_util/render_config_reader.c b/lib_util/render_config_reader.c
index b9bb2e5a609ade0167533ec651f1744a8badf162..ea06b8baf5debd6b886fbc1c8898cf3acd16cd85 100644
--- a/lib_util/render_config_reader.c
+++ b/lib_util/render_config_reader.c
@@ -2373,6 +2373,9 @@ ivas_error RenderConfigReader_read(
                 aeHasERsize = aeHasERabs = FALSE;
                 params_idx = 0;
                 pValue = (char *) calloc( strlen( pParams ), sizeof( char ) );
+#ifdef FIX_1452_DEFAULT_REVERB
+                hRenderConfig->roomAcoustics.acousticPreDelay = IVAS_REVERB_DEFAULT_SYNTH_PRE_DELAY;
+#endif
                 while ( sscanf( pParams + params_idx, "%64[^=]=%[^;];", item, pValue ) == 2 )
                 {
                     params_idx += (int32_t) ( strlen( item ) + strlen( pValue ) + 2 );
@@ -3032,6 +3035,9 @@ ivas_error RenderConfigReader_getAcousticEnvironment(
     {
         if ( id == pRenderConfigReader->pAE[n].id )
         {
+#ifdef FIX_1452_DEFAULT_REVERB
+            pAcEnv->aeID = (uint16_t) pRenderConfigReader->pAE[n].id;
+#endif
             pAcEnv->nBands = (int16_t) pRenderConfigReader->pAE[n].pFG->nrBands;
             pAcEnv->inputPreDelay = pRenderConfigReader->pAE[n].preDelay;
             for ( m = 0; m < pAcEnv->nBands; m++ )