diff --git a/src/SoundMaker/Sounds/WaveTypes/PseudoTriangleWave.cs b/src/SoundMaker/Sounds/WaveTypes/PseudoTriangleWave.cs
index c413a97..59477c8 100644
--- a/src/SoundMaker/Sounds/WaveTypes/PseudoTriangleWave.cs
+++ b/src/SoundMaker/Sounds/WaveTypes/PseudoTriangleWave.cs
@@ -26,12 +26,12 @@ public override short[] GenerateWave(SoundFormat format, int length, int volume,
         }
 
         var result = new List<short>(length);
-        var unitWave = GenerateUnitWave(format, volume, hertz);
-        for (var i = 0; i < length / unitWave.Count; i++)
+        var unitWave = GenerateUnitWaveInternal(format, volume, hertz);
+        for (var i = 0; i < length / unitWave.Length; i++)
         {
             result.AddRange(unitWave);
         }
-        for (var i = 0; i < length % unitWave.Count; i++)
+        for (var i = 0; i < length % unitWave.Length; i++)
         {
             result.Add(0);
         }
@@ -43,7 +43,23 @@ internal override WaveTypeBase Clone()
         return new PseudoTriangleWave();
     }
 
-    private List<short> GenerateUnitWave(SoundFormat format, int volume, double hertz)
+    /// <summary>
+    /// Generates one cycle of a sound waveform at the specified frequency.<br/>
+    /// 指定した周波数の音声波形1周期分を生成する。
+    /// </summary>
+    /// <param name="format">Format of the sound. <br/>音のフォーマット</param>
+    /// <param name="volume">Volume <br/>音量（0 ~ 100）</param>
+    /// <param name="hertz">Hertz of the sound. <br/>音の周波数</param>
+    /// <returns>The array of wave data.</returns>
+    /// <exception cref="ArgumentOutOfRangeException">Hertz must be non-negative and greater than 0.</exception>
+    /// <exception cref="ArgumentOutOfRangeException">Volume must be below 100 and above 0.</exception>
+    public short[] GenerateUnitWave(SoundFormat format, int volume, double hertz)
+    {
+        CheckGenerateUnitWaveArgs(volume, hertz);
+        return GenerateUnitWaveInternal(format, volume, hertz);
+    }
+
+    private static short[] GenerateUnitWaveInternal(SoundFormat format, int volume, double hertz)
     {
         var repeatNumber = (int)((int)format.SamplingFrequency / hertz);
 
@@ -77,6 +93,6 @@ private List<short> GenerateUnitWave(SoundFormat format, int volume, double hert
             }
         }
 
-        return result.ToList();
+        return result;
     }
 }
diff --git a/src/SoundMaker/Sounds/WaveTypes/SquareWave.cs b/src/SoundMaker/Sounds/WaveTypes/SquareWave.cs
index c576ee3..6c2dc0d 100644
--- a/src/SoundMaker/Sounds/WaveTypes/SquareWave.cs
+++ b/src/SoundMaker/Sounds/WaveTypes/SquareWave.cs
@@ -20,22 +20,22 @@ public SquareWave(SquareWaveRatio squareWaveRatio)
     /// <summary>
     /// デューティ比を基に繰り返し回数を求める為の値
     /// </summary>
-    private List<(double, double)> Ratio { get; } = new List<(double, double)>
-    {
+    private static List<(double, double)> Ratio { get; } =
+    [
         (0.875, 0.125),
         (0.75, 0.25),
         (0.5, 0.5),
-    };
+    ];
 
     public override short[] GenerateWave(SoundFormat format, int length, int volume, double hertz)
     {
         var result = new List<short>(length);
-        var unitWave = GenerateUnitWave(format, volume, hertz);
-        for (var i = 0; i < length / unitWave.Count; i++)
+        var unitWave = GenerateUnitWaveInternal(format, volume, hertz, SquareWaveRatio);
+        for (var i = 0; i < length / unitWave.Length; i++)
         {
             result.AddRange(unitWave);
         }
-        for (var i = 0; i < length % unitWave.Count; i++)
+        for (var i = 0; i < length % unitWave.Length; i++)
         {
             result.Add(0);
         }
@@ -47,9 +47,25 @@ internal override WaveTypeBase Clone()
         return new SquareWave(SquareWaveRatio);
     }
 
-    private List<short> GenerateUnitWave(SoundFormat format, int volume, double hertz)
+    /// <summary>
+    /// Generates one cycle of a sound waveform at the specified frequency.<br/>
+    /// 指定した周波数の音声波形1周期分を生成する。
+    /// </summary>
+    /// <param name="format">Format of the sound. <br/>音のフォーマット</param>
+    /// <param name="volume">Volume <br/>音量（0 ~ 100）</param>
+    /// <param name="hertz">Hertz of the sound. <br/>音の周波数</param>
+    /// <returns>The array of wave data.</returns>
+    /// <exception cref="ArgumentOutOfRangeException">Hertz must be non-negative and greater than 0.</exception>
+    /// <exception cref="ArgumentOutOfRangeException">Volume must be below 100 and above 0.</exception>
+    public short[] GenerateUnitWave(SoundFormat format, int volume, double hertz)
     {
-        var ratioIndex = (int)SquareWaveRatio;
+        CheckGenerateUnitWaveArgs(volume, hertz);
+        return GenerateUnitWaveInternal(format, volume, hertz, SquareWaveRatio);
+    }
+
+    private static short[] GenerateUnitWaveInternal(SoundFormat format, int volume, double hertz, SquareWaveRatio squareWaveRatio)
+    {
+        var ratioIndex = (int)squareWaveRatio;
         var allRepeatTimes = (int)((int)format.SamplingFrequency / hertz);
         var firstRepeatTimes = (int)(allRepeatTimes * Ratio[ratioIndex].Item1);
         // なぜか配列よりリストの方が早い
@@ -68,6 +84,6 @@ private List<short> GenerateUnitWave(SoundFormat format, int volume, double hert
         {
             result.Add(bottom);
         }
-        return result;
+        return result.ToArray();
     }
 }
diff --git a/src/SoundMaker/Sounds/WaveTypes/TriangleWave.cs b/src/SoundMaker/Sounds/WaveTypes/TriangleWave.cs
index a145d90..423e011 100644
--- a/src/SoundMaker/Sounds/WaveTypes/TriangleWave.cs
+++ b/src/SoundMaker/Sounds/WaveTypes/TriangleWave.cs
@@ -8,12 +8,12 @@ public override short[] GenerateWave(SoundFormat format, int length, int volume,
     {
         CheckGenerateWaveArgs(length, volume, hertz);
         var result = new List<short>(length);
-        var unitWave = GenerateUnitWave(format, volume, hertz);
-        for (var i = 0; i < length / unitWave.Count; i++)
+        var unitWave = GenerateUnitWaveInternal(format, volume, hertz);
+        for (var i = 0; i < length / unitWave.Length; i++)
         {
             result.AddRange(unitWave);
         }
-        for (var i = 0; i < length % unitWave.Count; i++)
+        for (var i = 0; i < length % unitWave.Length; i++)
         {
             result.Add(0);
         }
@@ -25,7 +25,23 @@ internal override WaveTypeBase Clone()
         return new TriangleWave();
     }
 
-    private List<short> GenerateUnitWave(SoundFormat format, int volume, double hertz)
+    /// <summary>
+    /// Generates one cycle of a sound waveform at the specified frequency.<br/>
+    /// 指定した周波数の音声波形1周期分を生成する。
+    /// </summary>
+    /// <param name="format">Format of the sound. <br/>音のフォーマット</param>
+    /// <param name="volume">Volume <br/>音量（0 ~ 100）</param>
+    /// <param name="hertz">Hertz of the sound. <br/>音の周波数</param>
+    /// <returns>The array of wave data.</returns>
+    /// <exception cref="ArgumentOutOfRangeException">Hertz must be non-negative and greater than 0.</exception>
+    /// <exception cref="ArgumentOutOfRangeException">Volume must be below 100 and above 0.</exception>
+    public short[] GenerateUnitWave(SoundFormat format, int volume, double hertz)
+    {
+        CheckGenerateUnitWaveArgs(volume, hertz);
+        return GenerateUnitWaveInternal(format, volume, hertz);
+    }
+
+    private static short[] GenerateUnitWaveInternal(SoundFormat format, int volume, double hertz)
     {
         var repeatNumber = (int)((int)format.SamplingFrequency / hertz);
 
@@ -58,6 +74,6 @@ private List<short> GenerateUnitWave(SoundFormat format, int volume, double hert
             result[halfCount + quarterCount + midOffsetFromHalfCount] = (short)(short.MinValue * volumeMagnification);
         }
 
-        return result.ToList();
+        return result;
     }
 }
diff --git a/src/SoundMaker/Sounds/WaveTypes/WaveTypeBase.cs b/src/SoundMaker/Sounds/WaveTypes/WaveTypeBase.cs
index a7323d3..0ce732f 100644
--- a/src/SoundMaker/Sounds/WaveTypes/WaveTypeBase.cs
+++ b/src/SoundMaker/Sounds/WaveTypes/WaveTypeBase.cs
@@ -25,6 +25,12 @@ protected void CheckGenerateWaveArgs(int length, int volume, double hertz)
         {
             throw new ArgumentOutOfRangeException(nameof(length), "'length' must be non-negative.");
         }
+
+        CheckGenerateUnitWaveArgs(volume, hertz);
+    }
+
+    protected static void CheckGenerateUnitWaveArgs(int volume, double hertz)
+    {
         if (volume is > 100 or < 0)
         {
             throw new ArgumentOutOfRangeException(nameof(volume), "'volume must be below than 100 and more than 0.");