diff --git a/SoundReceiver/Detector.cs b/SoundReceiver/Detector.cs
index d0d5ecf..cd23e9f 100644
--- a/SoundReceiver/Detector.cs
+++ b/SoundReceiver/Detector.cs
@@ -73,8 +73,11 @@ public byte[] Detect(short[] signal, List<double> bitLevels, out double? snr, ou
             double[] d23 = Integrate(d21, integrateBitLen2);
             if (debug) SaveWav("d23.wav", SignalDtoS(d23));
 
-            double[] d24 = new double[d22.Length - integrateBitLen2];
-            double[] d25 = new double[d22.Length - integrateBitLen2];
+            int d24len = d22.Length - integrateBitLen2;
+            if (d24len <= 0)
+                throw new SignalException("Not enough samples");
+            double[] d24 = new double[d24len];
+            double[] d25 = new double[d24len];
             MinMax(d22, integrateBitLen2, d24, d25);
 
             if (debug) SaveWav("d24.wav", SignalDtoS(d24));
@@ -200,7 +203,6 @@ public byte[] Detect(short[] signal, List<double> bitLevels, out double? snr, ou
 
 
             int deltaRange = Convert.ToInt32(estBitlen * 2);
-            //int deltaRange = 0;
 
             int eqSize = (int)(10 * estBitlen) | 1;
             Complex[] d3 = new Complex[signalEndFine - signalStartFine +
diff --git a/SoundReceiver/MainWindow.xaml.cs b/SoundReceiver/MainWindow.xaml.cs
index 4f58c0c..30f0374 100644
--- a/SoundReceiver/MainWindow.xaml.cs
+++ b/SoundReceiver/MainWindow.xaml.cs
@@ -65,6 +65,7 @@ void StartButton_Click(object sender, RoutedEventArgs e)
 
                 // WaveIn needs to be reinitialized each time:
                 // https://github.com/naudio/NAudio/issues/49#issuecomment-280446686
+                waveIn?.Dispose();
                 waveIn = new WaveIn();
                 waveIn.WaveFormat = new WaveFormat(44100, 1);
                 waveIn.DataAvailable += waveIn_DataAvailable;
@@ -80,6 +81,8 @@ void StartButton_Click(object sender, RoutedEventArgs e)
             {
                 if (ex.Result == MmResult.BadDeviceId)
                     MessageTextBox.Text = "[Recording device is not found]";
+                else
+                    MessageTextBox.Text = $"[Recording error: {ex.Result}]";
             }
         }
 
@@ -88,7 +91,6 @@ void StopButton_Click(object sender, RoutedEventArgs e)
             createWavFile = Keyboard.Modifiers.HasFlag(ModifierKeys.Control);
 
             waveIn.StopRecording();
-            waveIn = null;
             StopButton.IsEnabled = false;
         }