diff --git a/app/server/sonicpi/lib/sonicpi/note.rb b/app/server/sonicpi/lib/sonicpi/note.rb
index 9aaac05fd5..eee7a6dedc 100644
--- a/app/server/sonicpi/lib/sonicpi/note.rb
+++ b/app/server/sonicpi/lib/sonicpi/note.rb
@@ -13,6 +13,8 @@
 module SonicPi
   class Note
 
+    class InvalidNoteError < ArgumentError ; end ;
+
     NOTES_TO_INTERVALS =
       {c:  0,  C:  0,
        cs: 1,  CS: 1, cS: 1, Cs: 1,
@@ -59,7 +61,7 @@ class Note
 
     DEFAULT_OCTAVE = 4
 
-    MIDI_NOTE_RE = /(([a-gA-G])([sSbBfF]?))([-]?[0-9]*)/
+    MIDI_NOTE_RE = /\A(([a-gA-G])([sSbBfF]?))([-]?[0-9]*)\Z/
 
     attr_reader :pitch_class, :octave, :interval, :midi_note, :midi_string
 
@@ -97,7 +99,7 @@ def initialize(n, o=nil)
 
       m = MIDI_NOTE_RE.match n
 
-      raise "Invalid note: #{n}" unless m
+      raise InvalidNoteError, "Invalid note: #{n}" unless m
       @pitch_class = "#{m[2].capitalize}#{unify_sharp_flat_modifier(m[3])}".to_sym
 
       if o
diff --git a/app/server/sonicpi/test/test_note.rb b/app/server/sonicpi/test/test_note.rb
index cb205f8be1..0e6fbd0389 100644
--- a/app/server/sonicpi/test/test_note.rb
+++ b/app/server/sonicpi/test/test_note.rb
@@ -119,5 +119,13 @@ def test_init_Fs3_7
       assert_equal(6, n.interval)
       assert_equal(102, n.midi_note)
     end
+
+    def test_init_error_sam
+      assert_raise Note::InvalidNoteError do
+        Note.new(:sam)
+      end
+    end
   end
+
+
 end