diff --git a/bin/curvecalc b/bin/curvecalc
--- a/bin/curvecalc
+++ b/bin/curvecalc
@@ -424,6 +424,7 @@ def read_all_subs(graph):
     to add, the sub will be available"""
     subsDir = showconfig.subsDir()
     for filename in os.listdir(subsDir):
+        # parsing nt is faster, but it should try n3 format if the parsing fails
         graph.parse(os.path.join(subsDir, filename), format="n3")
 
 def makeGraph():