             expect(pitch.index).to(equal(-9))
             expect(pitch.note).to(equal(Note.C))
             expect(pitch.octave).to(equal(4))
-            expect(pitch.frequency).to(equal(261.626))
+            expect(pitch.frequency) ≈ (261.626, 0.01)
           }
 
           it("creates C#6") {

            expect(pitch).toNot(beNil())
            expect(pitch.note).to(equal(Note.A))
            expect(pitch.octave).to(equal(4))
            expect(pitch.frequency).to(equal(440))
          }

          it("creates A#0") {

            expect(pitch).toNot(beNil())
            expect(pitch.note).to(equal(Note.G))
            expect(pitch.octave).to(equal(1))
            expect(pitch.frequency) ≈ (48.9994, 0.01)
          }

          it("creates G#3") {
