diff --git a/audio-player.rkt b/audio-player.rkt
index da27b13..f32155b 100644
--- a/audio-player.rkt
+++ b/audio-player.rkt
@@ -78,7 +78,9 @@
       #f))
 
 (define-struct internal-audio-retval
-  (kind code info retval))
+  (kind code info retval)
+  #:transparent
+  )
 
 (define (to-ret-value ret)
   (if (list? ret)