diff --git a/src/i_3dsound.c b/src/i_3dsound.c
index 7cbbe226..0db1422e 100644
--- a/src/i_3dsound.c
+++ b/src/i_3dsound.c
@@ -22,6 +22,7 @@
 #include "i_oalsound.h"
 #include "r_data.h"
 #include "r_main.h"
+#include "p_setup.h"
 
 #define FIXED_TO_ALFLOAT(x) ((ALfloat)((double)(x) / FRACUNIT))
 
@@ -171,7 +172,8 @@ static void CalcDistance(const mobj_t *listener, const mobj_t *source,
     CalcHypotenuse(adx, ady, &distxy);
 
     // Treat monsters and projectiles as point sources.
-    src->point_source = (source->info && source->info->actualheight);
+    src->point_source = (source->thinker.function.v != (actionf_v)P_DegenMobjThinker &&
+                        source->info && source->info->actualheight);
 
     if (src->point_source)
     {
diff --git a/src/p_setup.c b/src/p_setup.c
index 0ce86b09..ebad8536 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -1209,6 +1209,11 @@ static void AddLineToSector(sector_t *s, line_t *l)
   *s->lines++ = l;
 }
 
+void P_DegenMobjThinker(void)
+{
+  // no-op
+}
+
 int P_GroupLines (void)
 {
   int i, total;
@@ -1263,6 +1268,8 @@ int P_GroupLines (void)
       sector->soundorg.y = (sector->blockbox[BOXTOP] + 
 			    sector->blockbox[BOXBOTTOM])/2;
 
+      sector->soundorg.thinker.function.v = (actionf_v)P_DegenMobjThinker;
+
       // adjust bounding box to map blocks
       block = (sector->blockbox[BOXTOP]-bmaporgy+MAXRADIUS)>>MAPBLOCKSHIFT;
       block = block >= bmapheight ? bmapheight-1 : block;
diff --git a/src/p_setup.h b/src/p_setup.h
index c1868ace..40c29018 100644
--- a/src/p_setup.h
+++ b/src/p_setup.h
@@ -41,6 +41,7 @@ extern mobj_t   **blocklinks;    // for thing chains
 extern boolean skipblstart; // MaxW: Skip initial blocklist short
 
 sector_t* GetSectorAtNullAddress(void);
+void P_DegenMobjThinker(void);
 
 #endif