diff --git a/midi.ts b/midi.ts
index eb844e5..15bc52e 100644
--- a/midi.ts
+++ b/midi.ts
@@ -358,7 +358,7 @@ namespace midi {
             } else {
                 left = mid;
             }
-            mid = (left + right) >> 1;
+            mid = ((left + right) >> 1) >> 0;
         }
         // imprecise match
         return frequency - notes[left] < notes[right] - frequency
diff --git a/tests.ts b/tests.ts
index bd840ca..1b1280a 100644
--- a/tests.ts
+++ b/tests.ts
@@ -8,3 +8,5 @@ i.setInstrument(MidiInstrument.Banjo);
 let piano = midi.channel(0);
 let trumpet = midi.channel(1);
 piano.setInstrument(MidiInstrument.Trumpet);
+
+serial.writeLine('B ' + Note.B + ' -> ' + midi.frequencyToKey(Note.B))