diff --git a/src/Audio/SoundFont/Gleitz.purs b/src/Audio/SoundFont/Gleitz.purs
index d30e3c8..3dbbe1f 100644
--- a/src/Audio/SoundFont/Gleitz.purs
+++ b/src/Audio/SoundFont/Gleitz.purs
@@ -8,7 +8,7 @@ module Audio.SoundFont.Gleitz (
   ) where
 
 
-import Prelude (class Show, (<>), ($), (+), (-), (*), map, negate, show)
+import Prelude (class Show, (<>), ($), (+), (*), map, negate, show)
 import Data.String.Regex as Regex
 import Data.String.Regex.Flags (noFlags)
 import Data.String (toUpper)
@@ -95,7 +95,7 @@ midiPitch1 s =
 -- | The MIDI standard does not standardise on a particular middle C
 toMidiPitch :: Int -> Int -> Int -> Int
 toMidiPitch octave pitch accidental =
-  (12 * octave) + pitch + accidental - 12
+  (12 * octave) + pitch + accidental + 12
 
 lookupPitch :: Pitch -> Maybe Int
 lookupPitch p =
diff --git a/test/Main.purs b/test/Main.purs
index c88e9f5..03b8ef7 100644
--- a/test/Main.purs
+++ b/test/Main.purs
@@ -16,15 +16,15 @@ gleitzSuite :: forall t. Free (TestF t) Unit
 gleitzSuite =
   suite "gleitz" do
     test "midi pitch C4" do
-      Assert.equal 36 (midiPitch "C4")
+      Assert.equal 60 (midiPitch "C4")
     test "midi pitch Bb1" do
-      Assert.equal 10 (midiPitch "Bb1")
+      Assert.equal 34 (midiPitch "Bb1")
     test "midi pitch A#1" do
-      Assert.equal 10 (midiPitch "A#1")
+      Assert.equal 34 (midiPitch "A#1")
     test "midi pitch A4" do
-      Assert.equal 45 (midiPitch "A4")
+      Assert.equal 69 (midiPitch "A4")
     test "midi pitch C8" do
-      Assert.equal 84 (midiPitch "C8")
+      Assert.equal 108 (midiPitch "C8")
 
 main :: forall t.
         Eff