diff --git a/lib_com/options.h b/lib_com/options.h
index b9dbd6e1f90c48e9be52848dec52eaeb49c78b3a..396d080b987e53349651476efc9c2f3084e60962 100755
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -173,6 +173,7 @@
 #define FIX_427_MAXIMUM_S_INDEX                         /* VA: issue 427: fix return index of function maximum_s() */
 #define FIX_431_PARAMMC_PLC_INTERPOLATOR                /* FhG: Issue 431: fix missing interpolator reset for ParamMC PCL */
 #define FIX_391_SBA                                     /* Dlb: Fix for issue 391 for SBA */
+#define LBR_ADAP_SMOOTHING_OPT                          /* FhG: Issue 436: complexity optimization of adaptive smoothing in low-bitrate SBA */
 
 #define FIX_425_MASA_BRSW_RENDERER                      /* Nokia: Issue 425: renderer not reconfigure in MASA bitrate switching */
 
diff --git a/lib_dec/ivas_spar_decoder.c b/lib_dec/ivas_spar_decoder.c
old mode 100644
new mode 100755
index 6f917a6f412b442c6582a1bc95145b6ec5316177..154d8c41f811272478dbf948f151c026d118b2a5
--- a/lib_dec/ivas_spar_decoder.c
+++ b/lib_dec/ivas_spar_decoder.c
@@ -1315,10 +1315,14 @@ void ivas_spar_dec_upmixer(
 
         if ( ( hDecoderConfig->ivas_total_brate < IVAS_24k4 ) && ( ( hDecoderConfig->output_config == AUDIO_CONFIG_HOA2 ) || ( hDecoderConfig->output_config == AUDIO_CONFIG_HOA3 ) ) )
         {
+#ifdef LBR_ADAP_SMOOTHING_OPT
+            ivas_spar_calc_smooth_facs( cldfb_in_ts_re[0], cldfb_in_ts_im[0], num_spar_bands, &hSpar->hFbMixer->pFb->fb_bin_to_band, hSpar->hMdDec->smooth_fac, hSpar->hMdDec->smooth_buf );
+#else
             for ( in_ch = 0; in_ch < numch_in; in_ch++ )
             {
                 ivas_spar_calc_smooth_facs( cldfb_in_ts_re[in_ch], cldfb_in_ts_im[in_ch], num_spar_bands, &hSpar->hFbMixer->pFb->fb_bin_to_band, hSpar->hMdDec->smooth_fac[in_ch], hSpar->hMdDec->smooth_buf[in_ch] );
             }
+#endif
         }
 
         for ( ts = 0; ts < MAX_PARAM_SPATIAL_SUBFRAMES; ts++ )
@@ -1334,7 +1338,11 @@ void ivas_spar_dec_upmixer(
                     {
                         for ( in_ch = 0; in_ch < numch_in; in_ch++ )
                         {
+#ifdef LBR_ADAP_SMOOTHING_OPT
+                            mixer_mat[out_ch][in_ch][spar_band] = ( 1 - hSpar->hMdDec->smooth_fac[spar_band] ) * mixer_mat[out_ch][in_ch][spar_band] + hSpar->hMdDec->smooth_fac[spar_band] * hSpar->hMdDec->mixer_mat_prev2[out_ch][in_ch][spar_band];
+#else
                             mixer_mat[out_ch][in_ch][spar_band] = ( 1 - hSpar->hMdDec->smooth_fac[in_ch][spar_band] ) * mixer_mat[out_ch][in_ch][spar_band] + hSpar->hMdDec->smooth_fac[in_ch][spar_band] * hSpar->hMdDec->mixer_mat_prev2[out_ch][in_ch][spar_band];
+#endif
                             hSpar->hMdDec->mixer_mat_prev2[out_ch][in_ch][spar_band] = mixer_mat[out_ch][in_ch][spar_band];
                         }
                     }
diff --git a/lib_dec/ivas_spar_md_dec.c b/lib_dec/ivas_spar_md_dec.c
old mode 100644
new mode 100755
index 9475c2f0264fa701d256a343438dbf5aad4bdef0..69f3754e5cafcc691af023f1408fbfc6ff0632b7
--- a/lib_dec/ivas_spar_md_dec.c
+++ b/lib_dec/ivas_spar_md_dec.c
@@ -618,6 +618,13 @@ ivas_error ivas_spar_md_dec_init(
     set_f( hMdDec->spar_md.en_ratio_slow, 0.0f, IVAS_MAX_NUM_BANDS );
     set_f( hMdDec->spar_md.ref_pow_slow, 0.0f, IVAS_MAX_NUM_BANDS );
 
+#ifdef LBR_ADAP_SMOOTHING_OPT
+    set_zero( hMdDec->smooth_fac, IVAS_MAX_NUM_BANDS );
+    for ( i = 0; i < IVAS_MAX_NUM_BANDS; i++ )
+    {
+        set_zero( hMdDec->smooth_buf[i], 2 * SBA_DIRAC_NRG_SMOOTH_LONG + 1 );
+    }
+#else
     for ( i = 0; i < IVAS_SPAR_MAX_CH; i++ )
     {
         set_zero( hMdDec->smooth_fac[i], IVAS_MAX_NUM_BANDS );
@@ -629,6 +636,7 @@ ivas_error ivas_spar_md_dec_init(
             set_zero( hMdDec->smooth_buf[i][j], 2 * SBA_DIRAC_NRG_SMOOTH_LONG + 1 );
         }
     }
+#endif
     for ( i = 0; i < IVAS_SPAR_MAX_CH; i++ )
     {
         for ( j = 0; j < IVAS_SPAR_MAX_CH; j++ )
diff --git a/lib_dec/ivas_stat_dec.h b/lib_dec/ivas_stat_dec.h
old mode 100644
new mode 100755
index 4174b2772b639f23dd900de43dde42543cae9127..69d03c03c52bd172deff5b584b910b18fd4175f1
--- a/lib_dec/ivas_stat_dec.h
+++ b/lib_dec/ivas_stat_dec.h
@@ -809,14 +809,17 @@ typedef struct ivas_spar_md_dec_state_t
     int16_t table_idx;
     int16_t dtx_vad;
     int16_t spar_hoa_md_flag;
-
 #ifdef SPAR_TUNING
     int16_t spar_hoa_dirac2spar_md_flag;
     int16_t HOA_md_ind[IVAS_SPAR_MAX_CH];
 #endif
-
+#ifdef LBR_ADAP_SMOOTHING_OPT
+    float smooth_buf[IVAS_MAX_NUM_BANDS][2 * SBA_DIRAC_NRG_SMOOTH_LONG + 1];
+    float smooth_fac[IVAS_MAX_NUM_BANDS];
+#else
     float smooth_buf[IVAS_SPAR_MAX_CH][IVAS_MAX_NUM_BANDS][2 * SBA_DIRAC_NRG_SMOOTH_LONG + 1];
     float smooth_fac[IVAS_SPAR_MAX_CH][IVAS_MAX_NUM_BANDS];
+#endif
     float mixer_mat_prev2[IVAS_SPAR_MAX_CH][IVAS_SPAR_MAX_CH][IVAS_MAX_NUM_BANDS];
 
 } ivas_spar_md_dec_state_t;