diff --git a/lib_com/options.h b/lib_com/options.h
index 33c1d943abfc7432f73bcfa0be919b3b46af84b7..c0cd3fbb39c3b43142a16560c6a5f78e3881be31 100644
--- a/lib_com/options.h
+++ b/lib_com/options.h
@@ -172,6 +172,7 @@
 #define FIX_FLOAT_1493_MASA_ENCODE_STABILITY_IMPROVE    /* Nokia: float issue 1493: Improves float decision stability in MASA encoding by adjusting reduction code */
 
 #define FIX_2432_ISM_SPIKES_16KHZ                       /* VA: basop issue 2432: fix spikes in ISM decoding at 16kHz output sampling rate */
+#define FIX_FLOAT_1518                                  /* FhG: fix issue 1518: loudness differences in OSBA decoding to mono or stereo output */
 
 /* ##################### End NON-BE switches ########################### */
 
diff --git a/lib_dec/ivas_cpe_dec.c b/lib_dec/ivas_cpe_dec.c
index fc1c85aaa4bfc46e3818fe2cc88743c03e5441cb..231b1ed866a570dde1f3779ae2d7c893865dd8fa 100644
--- a/lib_dec/ivas_cpe_dec.c
+++ b/lib_dec/ivas_cpe_dec.c
@@ -500,7 +500,14 @@ ivas_error ivas_cpe_dec(
 
     if ( hCPE->element_mode == IVAS_CPE_MDCT && hCPE->nchan_out == 1 && ( is_DTXrate( ivas_total_brate ) == 0 || ( is_DTXrate( ivas_total_brate ) == 1 && is_DTXrate( st_ivas->hDecoderConfig->last_ivas_total_brate ) == 0 ) ) )
     {
-        applyDmxMdctStereo( hCPE, output, output_frame );
+#ifdef FIX_FLOAT_1518
+        if ( !( st_ivas->ivas_format == SBA_ISM_FORMAT && st_ivas->ism_mode == ISM_MODE_NONE ) )
+        {
+#endif
+            applyDmxMdctStereo( hCPE, output, output_frame );
+#ifdef FIX_FLOAT_1518
+        }
+#endif
     }
 
 #ifndef DEBUG_STEREO_DFT_OUTRESPRED
diff --git a/lib_dec/ivas_dec.c b/lib_dec/ivas_dec.c
index bebc8a6a420c0d8150ee24176f427b290f60969a..f47dfb6118d4ac2201282414f56fbe0148ff0284 100644
--- a/lib_dec/ivas_dec.c
+++ b/lib_dec/ivas_dec.c
@@ -443,6 +443,12 @@ ivas_error ivas_dec(
 
             ivas_sba_dirac_stereo_dec( st_ivas, &p_output[sba_ch_idx], output_frame );
         }
+#ifdef FIX_FLOAT_1518
+        else if ( st_ivas->hDecoderConfig->nchan_out == 1 && st_ivas->ism_mode == ISM_MODE_NONE )
+        {
+            v_multc( p_output[0], 2.0f, p_output[0], output_frame );
+        }
+#endif
 
         /* HP filtering */
         for ( n = 0; n < getNumChanSynthesis( st_ivas ); n++ )
diff --git a/lib_dec/ivas_sba_dirac_stereo_dec.c b/lib_dec/ivas_sba_dirac_stereo_dec.c
index e2fed3b0ca8c993e60356c553d0e44d091e01543..ea3355769d01eefa04e51aa8886f802519616c40 100644
--- a/lib_dec/ivas_sba_dirac_stereo_dec.c
+++ b/lib_dec/ivas_sba_dirac_stereo_dec.c
@@ -910,7 +910,11 @@ 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_FLOAT_1518
+    if ( !sba_mono_flag && !( st_ivas->ivas_format == SBA_ISM_FORMAT && st_ivas->ism_mode == ISM_MODE_NONE ) )
+#else
     if ( !sba_mono_flag )
+#endif
     {
         v_multc( output[0], 0.5f, output[0], output_frame );
         v_multc( output[1], 0.5f, output[1], output_frame );
diff --git a/lib_dec/ivas_stereo_mdct_core_dec.c b/lib_dec/ivas_stereo_mdct_core_dec.c
index 2bd77a831cb49977db01621ce73457ff5bdc510c..4ba86bc7bd2d14c2a6adfb1871bd4e6a840c92d5 100644
--- a/lib_dec/ivas_stereo_mdct_core_dec.c
+++ b/lib_dec/ivas_stereo_mdct_core_dec.c
@@ -349,7 +349,11 @@ void stereo_mdct_core_dec(
 
     run_min_stats( sts, x );
 
+#ifdef FIX_FLOAT_1518
+    if ( hCPE->nchan_out == 1 && ( !bfi || ( bfi && sts[0]->core != ACELP_CORE && sts[1]->core != ACELP_CORE ) ) && !( st_ivas->ivas_format == SBA_ISM_FORMAT && st_ivas->ism_mode == ISM_MODE_NONE ) )
+#else
     if ( hCPE->nchan_out == 1 && ( !bfi || ( bfi && sts[0]->core != ACELP_CORE && sts[1]->core != ACELP_CORE ) ) )
+#endif
     {
         apply_dmx_weights( hCPE, x, sts[0]->transform_type, sts[1]->transform_type );
     }