I just finished mastering the Good Sponge Sampler Vol 2. Great original music from New London, CT

Take steps to avoid an “echoey” room. Build a $30 sound baffle!

Watch this video on how a guy created a vocal area in his bedroom $30 worth of stuff you can get online and at your neighborhood store (cheap Uhaul moving blankets and some hanging hooks). You can REALLY hear the difference!

Here’s a link to the YouTube Video: http://tinyurl.com/BaffleVideo

He uses two blankets, a quilted moving blanket which you can buy for $15 at http://tinyurl.com/QuiltedBlanket, and under that a regular furniture pad, which you can buy for $8 at http://tinyurl.com/FurniturePad.  You’ll also need $6 worth of hooks from Home Depot or any hardware store and a set of shower rings, which you can also get at any Wal-Mart for a few bucks.

If you don’t have a way to build something like this and you have a walk-in closet in your house? Record in there! You’ll be amazed at the difference in quality you can get in a closet full of clothes.

ROAD TRIP JOURNAL #2

I think we were driving through Iowa. I was working at the table in the back of the RV and I hear Richard say "Holy Crap! That was the biggest turbine blade I've ever seen!" I immediately look out the window to see ... nothing! I thought he was looking at a windmill. But no, he saw a single 100' turbine blade being driven down the highway strapped to a flatbed!

Of course, I didn't know this, so I go back to work. A few minutes later, Richard says "Holy Crap! Here comes another one!" This time, I look out the window and I see it.

Thinking on his feet, Richard says "Grab the camera! They come in threes!" I grab the camera and hand it up to Richard.

Sure enough, here comes another one. Snap! And then, another, and another...

Turns out Iowa is swimming in windmills. 

Automatically Adjust Input Gain During Speech Recognition

When we use speech recognition on our Windows 7 machine, the last thing most of us think about is the record level of our microphone. If it's too low, recognition will not be accurate because the system can't hear you proporly. If the level is too high you will overdrive the amplifier and again, the result is low accuracy.

If you are lucky enough to be a .NET developer you can use a neat little trick to automatically adjust the input gain.

Here's the XAML for a simple window that shows an audio level meter and a slider for manually adjusting the input gain: 

<Window x:Class="AudioGainTestCS.MainWindow"     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">
    <Grid Height="273" Width="427">
        <ProgressBar Height="37" HorizontalAlignment="Left" Margin="12,12,0,0" Name="ProgressBar1" VerticalAlignment="Top" Width="403" />
      <Slider Height="26" HorizontalAlignment="Left" Margin="12,55,0,0" Name="Slider1" VerticalAlignment="Top" Width="403" Orientation="Horizontal" Maximum="99" />
        <TextBox Height="175" HorizontalAlignment="Left" FontSize="30" TextWrapping="Wrap" Margin="14,86,0,0" Name="TextBox1" VerticalAlignment="Top" Width="401" />
    </Grid>
</Window>

C# Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace AudioGainTestCS
{
    /// <summary>
    /// This application automatically adjusts the record level (input volume)
    /// as you use speech recognition. A mismatched record level can be 
    /// disastrous if you're going to use speech recognition. Note that for
    /// this demo, I'm using a DictationGrammar, but it works with any grammar.
    /// 
    /// The key is the WaveLibMixer.dll, which you can find on CodeProject. 
    /// This library lets you get and set levels and other controls associated with
    /// audio devices.
    /// 
    /// The SpeechRecognitionEngine raises an event on a regular interval passing in
    /// the volume at the input device. When you are not speaking this level is close
    /// to zero. When you are shouting it's closer to 99.
    /// 
    /// Given the volume of speech over time and the ability to control the record level
    /// dynamically, well... it's pretty darned easy to automatically adjust the
    /// microphone for the speaker.
    /// 
    /// Don't get caught without this nice little tool!
    /// 
    /// Carl
    /// </summary>
    public partial class MainWindow : Window
    {
        // -- Add a reference to System.Speech
        private System.Speech.Recognition.SpeechRecognitionEngine speech = new System.Speech.Recognition.SpeechRecognitionEngine();
    
        // -- Add a reference to WaveLibMixer.dll, which you can find at:
        //    http://www.codeproject.com/Articles/11695/Audio-Library-Part-I-Windows-Mixer-Control
        private WaveLib.AudioMixer.MixerLine audioLine;
    
        private Int32 peakLevel;

        public MainWindow()
        {
            InitializeComponent();
            this.Loaded+=new RoutedEventHandler(MainWindow_Loaded);
            speech.AudioLevelUpdated+=new EventHandler<System.Speech.Recognition.AudioLevelUpdatedEventArgs>(speech_AudioLevelUpdated);
            speech.SpeechRecognized+=new EventHandler<System.Speech.Recognition.SpeechRecognizedEventArgs>(speech_SpeechRecognized);
            Slider1.ValueChanged += new RoutedPropertyChangedEventHandler<double>(Slider1_ValueChanged);
        }

   
        private void MainWindow_Loaded(object sender, System.Windows.RoutedEventArgs e) {
            // -- Create a new input mixer object to control an audio input device
            WaveLib.AudioMixer.Mixer audioMixer = new WaveLib.AudioMixer.Mixer(WaveLib.AudioMixer.MixerType.Recording);
            // -- Open the default recording device
            audioMixer.DeviceId = audioMixer.DeviceIdDefault;
            // -- Does the mixer have lines? It ought to...
            if ((audioMixer.Lines.Count > 0)) {
                // -- Select the first line, which is usually the Master Volume
                audioLine = audioMixer.Lines[0];
                // -- Does that line have a Volume control? It really ought to...
                if (audioLine.ContainsVolume) {
                    // -- Set the input volume (record level) to 50%
                    audioLine.Volume = audioLine.VolumeMax / 2;
                    // -- Set up the slider min/max and value based on the volume
                    Slider1.Minimum = audioLine.VolumeMin;
                    Slider1.Maximum = audioLine.VolumeMax;
                    Slider1.Value = audioLine.Volume;
                }
                else {
                    // -- Jeez... lame.
                    Slider1.IsEnabled = false;
                }
            }

            // -- The progress bar is used as an audio meter. 
            //    The speech recognition engine gives us a volume value from 0 to 99.
            //    So we set the ProgressBar min and max accordingly
            ProgressBar1.Minimum = 0;
            ProgressBar1.Maximum = 99;
            // -- Set the speech synthesizer to use the default audio input device
            speech.SetInputToDefaultAudioDevice();
            // -- Tell the speech synthesizer to recognize plain speech, not commands.
            speech.LoadGrammar(new System.Speech.Recognition.DictationGrammar());
            // -- Start recognizing
            speech.RecognizeAsync(System.Speech.Recognition.RecognizeMode.Multiple);
        }
    
        private void speech_AudioLevelUpdated(object sender, System.Speech.Recognition.AudioLevelUpdatedEventArgs e) {
            // -- This is an event handler that happens on a regular interval.
            //    The e.AudioLevel is a value from 0 to 99 representing the 
            //    volume of the talker's voice in almost real-time.
            // -- Setting the progressbar value to this level creates an audio meter.
            ProgressBar1.Value = e.AudioLevel;
            // -- If the volume is over 70% loud, knock the slider down a bit
            //    which will in turn drop the record level
            if ((e.AudioLevel > 70)) {
                Slider1.Value -= 1000;
            }
            // -- Keep track of the peak level for this sentence.
            if ((e.AudioLevel > peakLevel)) {
                peakLevel = e.AudioLevel;
            }
        }
    
        private void speech_SpeechRecognized(object sender, System.Speech.Recognition.SpeechRecognizedEventArgs e) {
            // -- This event handler fires after the talker speaks a sentence.
            //    e.Result.Text contains the text that they have spoken.
            // -- In this case, I'm capitalizing the sentence, adding a period at the end, 
            //    and displaying the text in a text box.
            TextBox1.Text = (e.Result.Text.Substring(0, 1).ToUpper() 
                        + (e.Result.Text.Substring(1) + "."));
            if ((peakLevel < 20)) {
                Slider1.Value += 3000;
            }
            // -- Reset the peak level
            peakLevel = 0;
        }

        void Slider1_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
        {
            // -- When the value of the slider changes, 
            //    set the audio input volume (the record level) to that value.
            //    This can happen when the user moves the slider, or some code
            //    sets the Slider1.Value 
            if (audioLine != null)
            {
                audioLine.Volume = (int)Slider1.Value;
            }
        }    
    }
}

Recovering Gracefully from Loss of Skeletal Tracking (Kinect For Windows)

The Kinect For Windows SDK v1.0 is awesome, but it doesn't recover well when it loses sight of you whilst tracking your skeleton. With a timer control and a little code to restart the KinectSensor, you can recover is 5 seconds or less.

This is the same code I use in GesturePak, a gesture recording and recognition SDK for Kinect for Windows.

Create a new WPF application and add a reference to the Kinect SDK assembly:

C:\Program Files\Microsoft SDKs\Kinect\v1.0\Assemblies\Microsoft.Kinect.dll

You don't need any controls for this demo. It simply turns the form red when tracking, and white when not tracking.

The basic idea is that when we lose tracking for the first time, you kick off a timer to fire it's Tick event in 1/2 a second. In the timer Tick handler you stop the Kinect Sensor, Start it up again, and then set the timer's Interval to a more reasonable amount of time. I use 5 seconds, but you should test it in your app. If it's too short, you don't give the Kinect time to track you, and if it's too long and it doesn''t track you, you could be sitting and waiting too long. 5 seconds seems reasonable to me.

When the state changes from not tracking to tracking, you simply disable the timer. 

Here's the code in both C# and VB.NET. In each case you can replace the default code behind MainWindow.xaml and run it. The C# app has to have a reference to System.Windows.Forms

C#

using System;

using System.Collections;

using System.Collections.Generic;

using System.Data;

using System.Diagnostics;

using System.Windows.Forms;

using System.Windows.Media;

using Microsoft.Kinect;

namespace TrackingTestCSharp

{

    /// <summary>

    /// This WPF demo shows you how gracefull recovery when the Kinect loses

    /// skeletal tracking. The Kinect device does not recover well on it's own.

    /// While restarting the Kinect may seem drastic, it's the only way I can 

    /// figure out how to do it. If you find a better way, email me at 

    /// carl@franklins.net. Thanks!

    /// </summary>

    /// <remarks></remarks>

    partial class MainWindow

    {

        private KinectSensor sensor;

        

        //-- boolean to keep track of the state

        private bool isTracking;

        //-- This is the interval after which the kinect is restarted the second 

        //   and subsequent times.

        private TimeSpan autoTrackingRecoveryInterval = TimeSpan.FromSeconds(5);

        //-- Timer used to restart

        private System.Windows.Threading.DispatcherTimer trackingRecoveryTimer = 

                new System.Windows.Threading.DispatcherTimer();

        public MainWindow()

        {

            Loaded += MainWindow_Loaded;

        }

        private void MainWindow_Loaded(object sender, System.Windows.RoutedEventArgs e)

        {

            //-- Make sure we have a sensor connected

            if (KinectSensor.KinectSensors.Count == 0) {

                MessageBox.Show("No Kinect Found");

                System.Windows.Application.Current.Shutdown();

            }

            //-- Start the first sensor, enabling the skeleton

            sensor = KinectSensor.KinectSensors[0];

            sensor.SkeletonStream.Enable(new TransformSmoothParameters());

            sensor.Start();

            //-- Hook the events

            sensor.SkeletonFrameReady += sensor_SkeletonFrameReady;

            trackingRecoveryTimer.Tick += trackingRecoveryTimer_Tick;

        }

        private void sensor_SkeletonFrameReady(object sender, Microsoft.Kinect.SkeletonFrameReadyEventArgs e)

        {

            //-- Get the frame

            dynamic frame = e.OpenSkeletonFrame();

            //-- Bail if it's nothing

            if (frame == null) return;

            using (frame) {

                //-- Bail if no data is returned.

                if (frame.SkeletonArrayLength == 0) return;

                //-- Get the data from the frame into an array

                Skeleton[] data = new Skeleton[frame.SkeletonArrayLength];

                frame.CopySkeletonDataTo(data);

                //-- Is there really no data?

                if (data.Length == 0) return

                //-- Is this skeleton being tracked?

                if (data[0].TrackingState == SkeletonTrackingState.Tracked) {

                    if (!isTracking) {

                        //-- If we weren't tracking, set the background to red

                        // to indicate that we are tracking

                        this.Background = Brushes.Red;

                        //-- we're tracking

                        isTracking = true;

                        //-- disable the timer

                        trackingRecoveryTimer.IsEnabled = false;

                        }

                 } else {

                     if (isTracking) {

                        //-- State changed from tracking to not tracking

                        isTracking = false;

                        //-- Set the background white to indicated we're NOT tracking

                        this.Background = Brushes.White;

                        //-- Since this is the first time we've lost tracking,

                        //   restart after 1/2 a second

                        trackingRecoveryTimer.Interval = TimeSpan.FromSeconds(0.5);

                        trackingRecoveryTimer.IsEnabled = true;
                    }

                }

            }

        }

        private void trackingRecoveryTimer_Tick(object sender, System.EventArgs e)

        {

            //-- Disable the timer

            trackingRecoveryTimer.IsEnabled = false;

            //-- If we're already tracking, bail. 

            if (isTracking) return;

             //-- Stop the sensor, ignoring errors

            try {

                sensor.Stop();

            } catch  {

            }

            //-- Start the sensor, ignoring errors

            try {

                sensor.Start();

            } catch  {

            }

            //-- Come back here in the defined interval

            trackingRecoveryTimer.Interval = autoTrackingRecoveryInterval;

            trackingRecoveryTimer.IsEnabled = true;

        }

    }

}

VB.NET

Imports Microsoft.Kinect
 
''' <summary>
''' This WPF demo shows you how gracefull recovery when the Kinect loses
''' skeletal tracking. The Kinect device does not recover well on it's own.
''' While restarting the Kinect may seem drastic, it's the only way I can 
''' figure out how to do it. If you find a better way, email me at 
''' carl@franklins.net. Thanks!
''' </summary>
''' <remarks></remarks>
Class MainWindow
 
    Private WithEvents sensor As KinectSensor
 
    Private isTracking As Boolean   '-- boolean to keep track of the state
 
    '-- This is the interval after which the kinect is restarted the second 
    '   and subsequent times.
    Private autoTrackingRecoveryInterval = TimeSpan.FromSeconds(5)
 
    '-- Timer used to restart
    Private WithEvents trackingRecoveryTimer As New Windows.Threading.DispatcherTimer
 
    Private Sub MainWindow_Loaded(sender As Object, e As System.Windows.RoutedEventArgs) Handles Me.Loaded
        '-- Make sure we have a sensor connected
        If KinectSensor.KinectSensors.Count = 0 Then
            MessageBox.Show("No Kinect Found")
            Application.Current.Shutdown()
        End If
 
        '-- Start the first sensor, enabling the skeleton
        sensor = KinectSensor.KinectSensors(0)
        sensor.SkeletonStream.Enable(New TransformSmoothParameters)
        sensor.Start()
    End Sub
 
    Private Sub sensor_SkeletonFrameReady(sender As Object, e As Microsoft.Kinect.SkeletonFrameReadyEventArgs) Handles sensor.SkeletonFrameReady
        '-- Get the frame
        Dim frame = e.OpenSkeletonFrame
        '-- Bail if it's nothing
        If frame Is Nothing Then Return
 
        Using frame
            '-- Bail if no data is returned.
            If frame.SkeletonArrayLength = 0 Then Return
 
            '-- Get the data from the frame into an array
            Dim data(frame.SkeletonArrayLength - 1) As Skeleton
            frame.CopySkeletonDataTo(data)
 
            '-- Is there really no data?
            If data.Length = 0 Then Return
 
            '-- Is this skeleton being tracked?
            If data(0).TrackingState = SkeletonTrackingState.Tracked Then
                If Not isTracking Then
                    '-- If we weren't tracking, set the background to red
                    '   to indicate that we are tracking
                    Me.Background = Brushes.Red
                    '-- we're tracking
                    isTracking = True
                    '-- disable the timer
                    trackingRecoveryTimer.IsEnabled = False
                End If
            Else
                If isTracking Then
                    '-- State changed from tracking to not tracking
                    isTracking = False
                    '-- Set the background white to indicated we're NOT tracking
                    Me.Background = Brushes.White
                    '-- Since this is the first time we've lost tracking,
                    '   restart after 1/2 a second
                    trackingRecoveryTimer.Interval = TimeSpan.FromSeconds(0.5)
                    trackingRecoveryTimer.IsEnabled = True
                End If
            End If
 
        End Using
    End Sub
 
    Private Sub trackingRecoveryTimer_Tick(sender As Object, e As System.EventArgs) Handles trackingRecoveryTimer.Tick
        '-- Disable the timer
        trackingRecoveryTimer.IsEnabled = False
        '-- If we're already tracking, bail. 
        If isTracking Then Return
        '-- Stop the sensor, ignoring errors
        Try
            sensor.Stop()
        Catch ex As Exception
        End Try
        '-- Start the sensor, ignoring errors
        Try
            sensor.Start()
        Catch ex As Exception
        End Try
        '-- Come back here in the defined interval
        trackingRecoveryTimer.Interval = autoTrackingRecoveryInterval
        trackingRecoveryTimer.IsEnabled = True
    End Sub
End Class