diff --git a/source/sound/sound_environment_definitions.c b/source/sound/sound_environment_definitions.c
index 99794bb2..d15e58cd 100644
--- a/source/sound/sound_environment_definitions.c
+++ b/source/sound/sound_environment_definitions.c
@@ -8,6 +8,8 @@ symbols in this file:
 
 /* ---------- headers */
 
+#include "sound_environment_definitions.h"
+
 /* ---------- constants */
 
 /* ---------- macros */
@@ -18,6 +20,26 @@ symbols in this file:
 
 /* ---------- globals */
 
+struct sound_environment_definition const default_sound_environment=
+{
+	0,
+	0,
+	0,
+	0.f,
+	0.f,
+	0.f,
+	1.f,
+	0.5f,
+	0.f,
+	0.02f,
+	0.f,
+	0.04f,
+	1.f,
+	1.f,
+	5000.f,
+	{ 0 },
+};
+
 /* ---------- public code */
 
 /* ---------- private code */
diff --git a/source/sound/sound_environment_definitions.h b/source/sound/sound_environment_definitions.h
index e5dd8d70..618b1f05 100644
--- a/source/sound/sound_environment_definitions.h
+++ b/source/sound/sound_environment_definitions.h
@@ -8,16 +8,46 @@ header included in hcex build.
 #define __SOUND_ENVIRONMENT_DEFINITIONS_H
 #pragma once
 
+/* ---------- headers */
+
+#include "cseries.h"
+#include "math/real_math.h"
+
 /* ---------- constants */
 
 /* ---------- macros */
 
 /* ---------- structures */
 
+struct sound_environment_definition
+{
+	long unknown;
+	short priority;
+	short unused0;
+	real room_intensity;
+	real room_intensity_hf;
+	real room_rolloff;
+	real decay_time;
+	real decay_hf_ratio;
+	real reflections_intensity;
+	real reflections_delay;
+	real reverb_intensity;
+	real reverb_delay;
+	real diffusion;
+	real density;
+	real hf_reference;
+	byte unused1[16];
+};
+
+typedef char verify_sound_environment_definition_size[
+	sizeof(struct sound_environment_definition) == 0x48 ? 1 : -1];
+
 /* ---------- prototypes/EXAMPLE.C */
 
 /* ---------- globals */
 
+extern struct sound_environment_definition const default_sound_environment;
+
 /* ---------- public code */
 
 #endif // __SOUND_ENVIRONMENT_DEFINITIONS_H