diff --git a/lib_com/options.h b/lib_com/options.h
index d573f13932eb7745079bf1ecb0368e572c4e453f..39d975a8f5ee3feb1031452dba7384a3abc60528 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -172,6 +172,8 @@
 /* any switch which is non-be wrt. TS 26.258 V3.0 */
 
 #define USE_RTPDUMP                                     /* FhG: RTPDUMP format (rtptools standard) instead of custom format */
+#define FIX_1521_SBA_LOUDNESS_STEREO                    /* FhG: issue 1521: Fix loudness for SBA to stereo rendering */
+#define FIX_1521_SBA_LOUDNESS_BINAURAL                  /* FhG: issue 1521: Fix loudness for SBA to binaural rendering */
 #define FIX_1540_EXPOSE_PT_IN_RTP_HEADER_API            /* Expose Payload Type setting in RTP Header */
 #define FIX_BASOP_2023_TDREND_DISTATT_PRECISION         /* Eri: Basop issue 2023: Distance attenuation scaling, synch with BASOP updates and adding clamping of distance att input and listener position  */
 #define FIX_1574_EFAP_CODE_LINT                         /* FhG: issue 1574: Code quality fixes in ivas_efap.c */
diff --git a/lib_dec/ivas_dec_render.c b/lib_dec/ivas_dec_render.c
index cfef84e48c96dab97891d441d11123fb85564f47..278bb18ac5ac20f7c8519da933747d25a5f5328f 100644
--- a/lib_dec/ivas_dec_render.c
+++ b/lib_dec/ivas_dec_render.c
@@ -341,6 +341,22 @@ ivas_error ivas_dec_render(
                 return error;
             }
         }
+#ifdef FIX_1521_SBA_LOUDNESS_BINAURAL
+        if ( st_ivas->ivas_format == SBA_FORMAT &&
+             ( st_ivas->renderer_type == RENDERER_BINAURAL_PARAMETRIC ||
+               st_ivas->renderer_type == RENDERER_BINAURAL_PARAMETRIC_ROOM ||
+                             st_ivas->renderer_type == RENDERER_BINAURAL_FASTCONV ) &&
+                         output_config != IVAS_AUDIO_CONFIG_BINAURAL_SPLIT_CODED &&
+                         output_config != IVAS_AUDIO_CONFIG_BINAURAL_SPLIT_PCM )
+        {
+            /* loudness correction for SBA binaural rendering */
+            nchan_out_syn_output = ( st_ivas->hSplitBinRend != NULL ) ? st_ivas->hSplitBinRend->splitrend.multiBinPoseData.num_poses * BINAURAL_CHANNELS : BINAURAL_CHANNELS;
+            for ( n = 0; n < nchan_out_syn_output; n++ )
+            {
+                v_multc( p_output[n], INV_SQRT2, p_output[n], *nSamplesRendered );
+            }
+        }
+#endif
     }
     else if ( st_ivas->ivas_format == MASA_ISM_FORMAT )
     {
diff --git a/lib_dec/ivas_sba_dirac_stereo_dec.c b/lib_dec/ivas_sba_dirac_stereo_dec.c
index e074d13f7e8756427e3e6d8c6ab2e3a070e8c437..fcc4f941244363590c434f075095a6ff13a2ccd1 100644
--- a/lib_dec/ivas_sba_dirac_stereo_dec.c
+++ b/lib_dec/ivas_sba_dirac_stereo_dec.c
@@ -910,10 +910,29 @@ void ivas_sba_dirac_stereo_dec(
     synchro_synthesis( st_ivas->hDecoderConfig->ivas_total_brate, hCPE, output, output_frame, 1 /*st_ivas->sba_dirac_stereo_flag*/ );
 
     /* output scaling */
+#ifdef FIX_1521_SBA_LOUDNESS_STEREO
+    if ( !sba_mono_flag )
+#else
     if ( !sba_mono_flag && !( st_ivas->ivas_format == SBA_ISM_FORMAT && st_ivas->ism_mode == ISM_MODE_NONE ) )
+#endif
     {
+#ifdef FIX_1521_SBA_LOUDNESS_STEREO
+        if ( st_ivas->ivas_format == SBA_ISM_FORMAT && st_ivas->ism_mode == ISM_MODE_NONE )
+        {
+            /* low bitrate OSBA needs a makeup gain of 2.f to compensate for the encoder side
+                INV_SQRT2 * 2 = SQRT2  */
+            v_multc( output[0], SQRT2, output[0], output_frame );
+            v_multc( output[1], SQRT2, output[1], output_frame );
+        }
+        else
+        {
+            v_multc( output[0], INV_SQRT2, output[0], output_frame );
+            v_multc( output[1], INV_SQRT2, output[1], output_frame );
+        }
+#else
         v_multc( output[0], 0.5f, output[0], output_frame );
         v_multc( output[1], 0.5f, output[1], output_frame );
+#endif
     }
 
     /* delay HB synth */
diff --git a/lib_dec/lib_dec.c b/lib_dec/lib_dec.c
index 63f78a94903e16f22cc54966c4b626f9cfa7fe79..7430e9e6fc691f75f60ee05559a238b8e762a0fa 100644
--- a/lib_dec/lib_dec.c
+++ b/lib_dec/lib_dec.c
@@ -2250,6 +2250,19 @@ static ivas_error isar_generate_metadata_and_bitstream(
         return error;
     }
 
+#ifdef FIX_1521_SBA_LOUDNESS_BINAURAL
+    if ( pcm_out_flag && st_ivas->ivas_format == SBA_FORMAT &&
+         ( st_ivas->renderer_type == RENDERER_BINAURAL_PARAMETRIC ||
+           st_ivas->renderer_type == RENDERER_BINAURAL_PARAMETRIC_ROOM ||
+           st_ivas->renderer_type == RENDERER_BINAURAL_FASTCONV ) )
+    {
+        for ( i = 0; i < st_ivas->hDecoderConfig->nchan_out; ++i )
+        {
+            v_multc( p_head_pose_buf[i], INV_SQRT2, p_head_pose_buf[i], nSamples );
+        }
+    }
+#endif
+
     return IVAS_ERR_OK;
 }
 
diff --git a/lib_rend/ivas_allrad_dec.c b/lib_rend/ivas_allrad_dec.c
index 141e538817c686b0e3b282e38567b1434d325866..5b27c04cb982a81ea66d9aef94b7fb52ac994ab7 100644
--- a/lib_rend/ivas_allrad_dec.c
+++ b/lib_rend/ivas_allrad_dec.c
@@ -129,10 +129,17 @@ ivas_error ivas_sba_get_hoa_dec_matrix(
     }
     else if ( hOutSetup.output_config == IVAS_AUDIO_CONFIG_STEREO )
     {
+#ifdef FIX_1521_SBA_LOUDNESS_STEREO
+        ( *hoa_dec_mtx )[0] = INV_SQRT2;
+        ( *hoa_dec_mtx )[1] = INV_SQRT2;
+        ( *hoa_dec_mtx )[SBA_NHARM_HOA3] = INV_SQRT2;
+        ( *hoa_dec_mtx )[SBA_NHARM_HOA3 + 1] = -INV_SQRT2;
+#else
         ( *hoa_dec_mtx )[0] = 0.5f;
         ( *hoa_dec_mtx )[1] = 0.5f;
         ( *hoa_dec_mtx )[SBA_NHARM_HOA3] = 0.5f;
         ( *hoa_dec_mtx )[SBA_NHARM_HOA3 + 1] = -0.5f;
+#endif
     }
     else if ( hOutSetup.is_loudspeaker_setup )
     {
diff --git a/lib_rend/ivas_crend.c b/lib_rend/ivas_crend.c
index 6befa436ab77aff92117622557821adb370982ad..e2abbd34179acad3f4ad33ed473990dcb88b023a 100644
--- a/lib_rend/ivas_crend.c
+++ b/lib_rend/ivas_crend.c
@@ -1854,7 +1854,19 @@ ivas_error ivas_rend_crendProcessSubframe(
         for ( ch = 0; ch < BINAURAL_CHANNELS; ch++ )
         {
             /* move to output */
-            mvr2r( pcm_tmp[ch], p_output[ch], subframe_len );
+#ifdef FIX_1521_SBA_LOUDNESS_BINAURAL
+            if ( inConfigType == IVAS_REND_AUDIO_CONFIG_TYPE_AMBISONICS && outConfig != IVAS_AUDIO_CONFIG_BINAURAL_ROOM_IR )
+            {
+                /* loudness correction for SBA binaural rendering */
+                v_multc( pcm_tmp[ch], INV_SQRT2, p_output[ch], subframe_len );
+            }
+            else
+            {
+#endif
+                mvr2r( pcm_tmp[ch], p_output[ch], subframe_len );
+#ifdef FIX_1521_SBA_LOUDNESS_BINAURAL
+            }
+#endif
 
             p_output[ch] += subframe_len;
         }