             baseTuning[i] *= 2.0
         }
 
-        // Gbまでは上がってGからは下がる
+        // Go up til Gb and go down after G
         let indexBoundary = 6  // index of Gb
         let indexOfTranspositionNote = find(sounds, transpositionNote)
         if (indexBoundary < indexOfTranspositionNote) {

        return [offset1, offset2, offset3, offset4, offset5, offset6, 
               offset7, offset8, offset9, offset10, offset11, offset12]
    }
    
    /*
    *  指定ルート音を最初の要素とした配列を生成
    */
    private class func arrangeSoundNamesForRootSound(rootSound: SoundName) -> [SoundName] {
        let soundNames: [SoundName] = [
            SoundBaseA,  SoundBaseBb, SoundBaseB, SoundBaseC,  SoundBaseDb, SoundBaseD,

        }
        return tuning
    }
 
    // Generate 12 frequencies for spacified octave by integral multiplication 
    private class func generateForOctave(octave: Int, tuningBase: [SoundName: Float]) -> [SoundName: Float] {
        var tuningForCurrentOctave = [SoundName: Float]()
        for key in tuningBase.keys {
