diff --git a/lib_com/options.h b/lib_com/options.h
old mode 100644
new mode 100755
index 801fd7ed9eed71713524ff84b2f52ed68104faf9..4fb0a0b58b663b7f74a8b6ec295cf4e925439f6f
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -168,7 +168,7 @@
 #endif
 #define NONBE_FIX_874_OMASA_BRSW_2TD                          /* Nokia: issue 874: Fixes the crashes with the long test vectors that prompted switching to TD*/
 #define NONBE_FIX_871_ACELP_CRASH_IN_OSBA                     /* FhG: isse 871: crash in ACELP core encoder with OSBA */
-
+#define NONBE_FIX_906_SBA_LBR_SMOOTHING                       /* FhG: issue #906: fix SBA low bit rate smoothing for HOA2/HOA3 output */
 /* ##################### End NON-BE switches ########################### */
 
 /* ################## End DEVELOPMENT switches ######################### */
diff --git a/lib_dec/ivas_spar_decoder.c b/lib_dec/ivas_spar_decoder.c
index 0237a059a5b259878f0f097541319eb86daae255..76e5c6f1fbad8ce91e4e4f49f68f30614349d1e5 100644
--- a/lib_dec/ivas_spar_decoder.c
+++ b/lib_dec/ivas_spar_decoder.c
@@ -1062,6 +1062,10 @@ static void ivas_spar_calc_smooth_facs(
     float *cldfb_in_ts_re[CLDFB_NO_COL_MAX],
     float *cldfb_in_ts_im[CLDFB_NO_COL_MAX],
     int16_t nbands_spar,
+#ifdef NONBE_FIX_906_SBA_LBR_SMOOTHING
+    const int16_t nSlots,
+    const int16_t isFirstSubframe,
+#endif
     ivas_fb_bin_to_band_data_t *bin2band,
     float *smooth_fac,
     float smooth_buf[IVAS_MAX_NUM_BANDS][2 * SBA_DIRAC_NRG_SMOOTH_LONG + 1] )
@@ -1083,15 +1087,30 @@ static void ivas_spar_calc_smooth_facs(
         subframe_band_nrg[b] = 0.f;
         while ( bin < CLDFB_NO_CHANNELS_MAX && b == bin2band->p_cldfb_map_to_spar_band[bin] )
         {
+#ifdef NONBE_FIX_906_SBA_LBR_SMOOTHING
+            for ( ts = 0; ts < nSlots; ts++ )
+#else
             for ( ts = 0; ts < MAX_PARAM_SPATIAL_SUBFRAMES; ts++ )
+#endif
             {
                 subframe_band_nrg[b] += cldfb_in_ts_re[ts][bin] * cldfb_in_ts_re[ts][bin] + cldfb_in_ts_im[ts][bin] * cldfb_in_ts_im[ts][bin];
             }
             bin++;
         }
         subframe_band_nrg[b] = sqrtf( subframe_band_nrg[b] );
-        smooth_buf[b][0] = subframe_band_nrg[b];
-
+#ifdef NONBE_FIX_906_SBA_LBR_SMOOTHING
+        if ( isFirstSubframe && nSlots < MAX_PARAM_SPATIAL_SUBFRAMES )
+        {
+            /* fill up to full 5ms subframe */
+            smooth_buf[b][0] += subframe_band_nrg[b];
+        }
+        else
+        {
+#endif
+            smooth_buf[b][0] = subframe_band_nrg[b];
+#ifdef NONBE_FIX_906_SBA_LBR_SMOOTHING
+        }
+#endif
         /* calculate short and long energy averages */
         smooth_short_avg[b] = EPSILON;
         for ( i = 0; i < 2 * SBA_DIRAC_NRG_SMOOTH_SHORT; i++ )
@@ -1128,14 +1147,21 @@ static void ivas_spar_calc_smooth_facs(
         smooth_fac[b] = max( min_smooth_gains1[b], min( max_smooth_gains2[b], smooth_fac[b] ) );
     }
 
-    for ( b = 0; b < nbands_spar; b++ )
+#ifdef NONBE_FIX_906_SBA_LBR_SMOOTHING
+    /* only update if we collected a full 5ms worth of energies for the buffer */
+    if ( isFirstSubframe || nSlots == MAX_PARAM_SPATIAL_SUBFRAMES )
     {
-        for ( i = 2 * SBA_DIRAC_NRG_SMOOTH_LONG; i > 0; i-- )
+#endif
+        for ( b = 0; b < nbands_spar; b++ )
         {
-            smooth_buf[b][i] = smooth_buf[b][i - 1];
+            for ( i = 2 * SBA_DIRAC_NRG_SMOOTH_LONG; i > 0; i-- )
+            {
+                smooth_buf[b][i] = smooth_buf[b][i - 1];
+            }
         }
+#ifdef NONBE_FIX_906_SBA_LBR_SMOOTHING
     }
-
+#endif
     return;
 }
 
@@ -1685,7 +1711,11 @@ void ivas_spar_dec_upmixer_sf(
 
     if ( ( hDecoderConfig->ivas_total_brate < IVAS_24k4 ) && ( ( hDecoderConfig->output_config == IVAS_AUDIO_CONFIG_HOA2 ) || ( hDecoderConfig->output_config == IVAS_AUDIO_CONFIG_HOA3 ) ) )
     {
+#ifdef NONBE_FIX_906_SBA_LBR_SMOOTHING
+        ivas_spar_calc_smooth_facs( cldfb_in_ts_re[0], cldfb_in_ts_im[0], num_spar_bands, hSpar->subframe_nbslots[hSpar->subframes_rendered], hSpar->subframes_rendered == 0, &hSpar->hFbMixer->pFb->fb_bin_to_band, hSpar->hMdDec->smooth_fac, hSpar->hMdDec->smooth_buf );
+#else
         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 );
+#endif
     }
 
     for ( ts = 0; ts < hSpar->subframe_nbslots[hSpar->subframes_rendered]; ts++ )