diff --git a/src/common/audio/sound/s_sound.cpp b/src/common/audio/sound/s_sound.cpp
index 74393dfdd..cdd0361c5 100644
--- a/src/common/audio/sound/s_sound.cpp
+++ b/src/common/audio/sound/s_sound.cpp
@@ -388,7 +388,7 @@ FSoundChan *SoundEngine::StartSound(int type, const void *source,
 	FVector3 pos, vel;
 	FRolloffInfo *rolloff;
 
-	if (sound_id <= 0 || volume <= 0 || nosfx || !SoundEnabled() || blockNewSounds)
+	if (sound_id <= 0 || volume <= 0 || nosfx || !SoundEnabled() || blockNewSounds || (unsigned)sound_id >= S_sfx.Size())
 		return NULL;
 
 	// prevent crashes.
diff --git a/src/sound/s_advsound.cpp b/src/sound/s_advsound.cpp
index 7d37c9952..f508c187f 100644
--- a/src/sound/s_advsound.cpp
+++ b/src/sound/s_advsound.cpp
@@ -416,7 +416,7 @@ static int S_AddSound (const char *logicalname, int lumpnum, FScanner *sc)
 
 	sfxid = soundEngine->FindSoundNoHash (logicalname);
 
-	if (sfxid > 0)
+	if ((unsigned int)sfxid < S_sfx.Size())
 	{ // If the sound has already been defined, change the old definition
 		sfxinfo_t *sfx = &S_sfx[sfxid];