diff --git a/LEGO1/mxbackgroundaudiomanager.cpp b/LEGO1/mxbackgroundaudiomanager.cpp
index c7f4db9b..f6f4df11 100644
--- a/LEGO1/mxbackgroundaudiomanager.cpp
+++ b/LEGO1/mxbackgroundaudiomanager.cpp
@@ -1,5 +1,7 @@
 #include "mxbackgroundaudiomanager.h"
 
+DECOMP_SIZE_ASSERT(MxBackgroundAudioManager, 0x150)
+
 // OFFSET: LEGO1 0x1007ea90
 MxBackgroundAudioManager::MxBackgroundAudioManager()
 {
@@ -39,4 +41,4 @@ void MxBackgroundAudioManager::Init()
 {
   this->m_unka0 = 0;
   this->m_unk13c = 0;
-}
\ No newline at end of file
+}