diff -rupN fluidsynth-1.1.9.org/src/utils/fluid_sys.c fluidsynth-1.1.9/src/utils/fluid_sys.c
--- fluidsynth-1.1.9.org/src/utils/fluid_sys.c	2018-01-02 10:14:56.000000000 -0500
+++ fluidsynth-1.1.9/src/utils/fluid_sys.c	2018-01-06 14:54:26.602393220 -0500
@@ -342,14 +342,16 @@ fluid_is_midifile(const char *filename)
  * @param filename Path to the file to check
  * @return TRUE if it could be a SoundFont, FALSE otherwise
  *
- * The current implementation only checks for the "RIFF" header in the file.
- * It is useful only to distinguish between SoundFont and MIDI files.
+ * The current implementation only checks for the "RIFF" and *sfbk* headers in
+ * the file.
+ * It is useful to distinguish between SoundFont and other (e.g. MIDI) files.
  */
 int
 fluid_is_soundfont(const char *filename)
 {
   FILE* fp = fopen(filename, "rb");
   char id[4];
+  int rval = 0;
 
   if (fp == NULL) {
     return 0;
@@ -358,9 +360,14 @@ fluid_is_soundfont(const char *filename)
     fclose(fp);
     return 0;
   }
-  fclose(fp);
 
-  return strncmp(id, "RIFF", 4) == 0;
+  if (strncmp(id, "RIFF", 4) == 0)
+    if (fseek(fp, 8, SEEK_SET) == 0)
+      if (fread((void*) id, 1, 4, fp) == 4)
+	if (strncmp(id, "sfbk", 4) == 0)
+	  rval = 1;
+  fclose(fp);
+  return rval;
 }
 
 /**