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Sound on the Web
http://advance.engj.ulst.ac.uk/multimedia/d
  ata/index_sound_on_web.htm
  •   Sound In Multimedia
  •   Multimedia Sound Formats
  •   What Format To Use
  •   Adding Sound To Web Pages
                                                       2/46




What is Sound?
 Identify what sound is
 Identify how sound works
 Understand what is meant by wavelengths,
  frequency and amplitude
 Identify examples of sound levels


http://advance.engj.ulst.ac.uk/multimedia/data/soundmulti
   media_soundforge/02_Overview/CD_2.htm
                                                 3/46




Introduction to Sound
 Sound is a longitudinal (back and forwards
  movement along the direction travelled)
  wave that can travel through gases (air),
  liquids (under water) or solids (the Earth).
                                                          4/46




Introduction to Sound
   Compressible waves have Wavelengths. The distance
    between two areas of compression or rarefaction is the
    wavelength. The number of waves that pass a certain
    point in one second is the Frequency (measured in cycles
    per second or Hertz (Hz))
   The size of the area of compression is similar to the
    Amplitude. The Amplitude of the wave is measured from
    the peak/trough to the midpoint.
   The intensity of sound waves
    produce a sound pressure level,
    which is commonly measured in a
    unit, called the Decibel.
                        5/46




Introduction to Sound
                                                                                6/46




Analogue and Digital
   Analogue signal will resemble the original speech or music by having the
    frequency or amplitude of the wave go up and down in the same way as the
    sound in speech or music goes up and down.
   The word analogue means similar or corresponding.
   Information in the form of an analogue signal can be added to another
    electromagnetic wave, which is used for transmission. This wave carries the
    analogue signal and is called the carrier wave. For much of the last century
    information was transmitted in the form of analogue signals.

   Digital Signal uses a code with two states that are called on and off. The on
    state is a small pulse of the electromagnetic wave. The off state is the gap in
    between the pulses where there is no electromagnetic wave.
   When the digital signal reaches its destination the series of on and off states
    must be changed back into the original information. This process is called
    decoding.
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Analogue to Digital Conversion
 Devices exist which convert from analogue
  signals to digital signals and vice-versa.
 Although most signals that we can perceive in the
  real world are analogue (sound levels in speech,
  light levels in vision etc.) more and more signals
  are being stored in digital format (audio CDs,
  DVDs, digital audio cassettes etc.)
 The problem with all signals is that they acquire
  noise
 Noise is any unwanted change to a signal that
  tends to corrupt it.
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Nyquist Thoery
http://advance.engj.ulst.ac.uk/multimedia/data/soundmultimedia_sou
   ndforge/02_Overview/2_04/snd_sf7_004b.pdf?
 To reproduce a waveform you need to sample the variation of sound
   at least twice every period of that waveform.
 In computer terms, the amplitude (or voltage) is measured in bits.
   Every bit keeps the value of the amplitude (or voltage) as a binary
   number. The more you have bits, the more you have values.

   When sound is converted from analogue into digital audio, the
    hardware "samples" the level of the waveform at a specific interval.
    For CD audio, this interval is 1/44,100th of a second.
   In other words, 44,100 times each second a special chip calculates a
    value for analogue input and sends it off for use or storage. This
    process is called "digitizing" a sound.
                                                         9/46




Sample Rate
  In developing an audio sound for computers or
   telecommunication, the sample rate is the number of
   samples of a sound that are taken per second to
   represent the event digitally.
 The more samples taken per second, the more accurate
   the digital representation of the sound can be. For
   example, the current sample rate for CD-quality audio is
 44,100 samples per second. This sample rate can
   accurately reproduce the audio frequencies up to 20,500
   hertz, covering the full range of human hearing.
http://advance.engj.ulst.ac.uk/multimedia/data/soundmulti
   media_soundforge/02_Overview/2_05/snd_sf7_005b.pd
   f?
Sound Forge


Essentials
                                           11/46




What is Sound Forge?
 Sound Forge is an audio editor that
  includes a powerful set of audio processes,
  tools and effects for recording and
  manipulating audio.
                                           12/46




Digital Trend
 Leisure has been revolutionised by Digital
  Audio
  • MP3
  • MIDI


 Sound Forge allows user to extract and
  record audio digitally
                                             13/46




What’s the Difference ?
 MIDI is note based
  • played through an instrument


 Digital Audio – MP3
  • Reproduction approximation of actual sound
                                            14/46




More about SoundForge
 About Sound Forge
 Why Use Sound Forge?
 Case Study - Sound in the Film Industry
                                                15/46




Contents
   Tour of Sound Forge
       – Audio files
       – Workspace
       – Data Window
   Working with Audio
       – Preparing and Importing Source Clips
   Editing Audio

   Producing Final Audio
       – CDROM / MP3
                                                   16/46




Tour of Sound Forge
 Typical Procedure
  •   Import of audio in digital format
  •   Editing of audio with data window timeline
  •   Producing a rough cut
  •   Refinement and addition of effects
       – Echo / pitch / volume
  • Export of completed digital audio
Equipment Requirements and
                                                                  17/46




Features
   PC
     • Sound Forge requires Microsoft DirectX Media
       6.0 or later and Internet
     • Explorer 4.0 or later.
   Sound Card
   Enhancements include:
    • Sound Forge can open and save audio files with any of the
      following bit depths:
        –   • 8-bit
        –   •16-bit
        –   • 24-bit integer
        –   • 32-bit float
   CD Ripping and MP3 output
                      18/46




Tour of Sound Forge
 Key windows
  • Menu




  • Timeline
                      19/46




Tour of Sound Forge
           20/46




Play Bar
                 21/46




Navigation Bar
                            22/46




Advanced Features Toolbar
                           23/46




Advanced Effects Toolbar
              24/46




Data Window
                25/46




Basic Editing
 Copying
 audio
                26/46




Basic Editing
 Paste audio
                                 27/46




Basic Editing – Adding Markers
                            28/46




Trimming / Cropping Audio
                              29/46




Zooming in
 Seeing more of the detail
                                           30/46




File Formats
 Sound Forge does not use a proprietary
  format
  • PC - .wav
     – .avi Video for Windows
     – .rm Real Media
     – .raw
         – Pulse Code Modulated
         – A-Law / m-Law


  • Mac - .aiff
        .snd
                                                 31/46




Recording Audio
   Prior to recording digital audio, you must
    understand that the:
    • Record and
    • Record Remote dialogs
  are destructive and contain no Undo capabilities.
 To avoid accidentally recording over valuable
  audio data, all incoming audio should be
  recorded into a new data window and
  subsequently pasted into the desired data
  window.
                  32/46




Recording Audio
                                                 33/46




Recording Audio in Remote Mode
   Clicking the Remote button places Sound Forge
    into Remote Recording mode. In this mode, the
    application’s workspace is hidden and replaced
    with the Record Remote dialog. The Remote
    Record dialog remains the topmost window
    regardless of the number of open applications.
    Remote recording is particularly useful when
    using an application that controls the input
    source, such as a mixer, CD audio, or MIDI
    sequencing.
              34/46




Remote Mode
                                               35/46




Extracting data from CD
 Choose Extract Audio from CD from the
  Tools menu. Sound Forge identifies the
  system’s CD-ROM drive(s). If the system is
  equipped with multiple CD-ROM drives, the
  desired drive must be selected from the
  Drive drop-down list.

 After the drive is selected, the Extract Audio
  from CD dialog is displayed and all tracks
  are listed.
                          36/46




Extracting data from CD
                                           37/46




Writing Audio to CD
 Sample rates deviating from 44,100 Hz will
  cause CD track lengths to be
  miscalculated. When attempting to write a
  file to CD that deviates from the 44,100 HZ
  sample rate, Sound Forge will prompt you to
  change the sample rate. Selecting Yes will
  automatically resample audio to 44,100 Hz.
                              38/46




Advanced Editing Techniques
 Drag-and-drop pasting
                                                                   39/46




Drag and Drop - Pasting
 Hold the ALT key and drag the selection to
  the data window.
  • A vertical dotted line representing the leading edge of the source
    selection is displayed in the destination window.

  • The letter “P” is
  displayed in
  the box
  Adjacent
  to the pointer.
                                                                     40/46




Drag and Drop - Mixing
   A shaded region representing the source selection is displayed in the
    destination window.
   An “M” is displayed in the box adjacent to the pointer.
   Position the leading edge of the shaded region in the Tutor1 data
    window where the mixing of the selection will begin.
   Release the mouse button. The Mix dialog is displayed.
                                                            41/46




Drag and Drop - Crossfading
   Hold the Ctrl key and drag the selection to the destination
    window.
   A shaded cross (or bowtie) region representing the
    source selection is displayed in the destination window.
   A “C” is displayed in the box adjacent to the pointer.
   Align the right edge of the shaded region with the right
    edge of the data in the destination window.
   Release the mouse button. The Crossfade dialog is
    displayed.
   Specify the desired crossfade in the Name drop-down list
    and click OK. The selection is crossfaded into the
    destination data and the file is adjusted accordingly.
                              42/46




Drag and Drop - Crossfading
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Drag and Drop - New
 Drag the selection to an empty area of the
  Sound Forge workspace and drop it. A new
  data window containing the selection data
  with the attributes of the original file is
  created.
                                                           44/46




Working with .avi Files
 Sound Forge supports opening and saving
  Microsoft Audio and Video Interleave (AVI) files.
 Using Sound Forge, you can edit an AVI file’s audio
  track with single-frame accuracy.
    • the file may contain only one video stream and one
      audio stream
                                                     45/46




Working with .avi Files
   Frame animation
     • When playing an AVI, you are able to specify if
       frames are animated or displayed as still frames.
       To turn on frame animation, right-click the video
       strip and choose Animate from the shortcut menu.
       A check mark is displayed adjacent to the
       command to indicate this feature is turned on.
   Using the cursor to select a frame
     • When Frame Animation is enabled, clicking
       anywhere within the audio portion of the data
       window displays the corresponding video frame in
       the video strip. This is a convenient method of
       viewing many individual frames, but does little to
       achieve frame-accurate synchronisation.
                                                             46/46




Working with .avi Files
   Video preview
    • To view a larger version of the AVI, choose Video Preview
      from the View menu during editing or playback. The current
      frame is displayed in Video Preview window.
                                                                  47/46




Saving .avi files with added Audio
   Saving an AVI in Sound Forge is essentially a
    three-step process that involves doing the
    following:
    • Specifying the audio and video streams to be saved.
    • Compressing the video.
    • Compressing the audio.


      When using compression algorithms, you must strike a balance
      between video quality, size reduction, and
      compression/decompression processing time. Applying extreme
      compression to video often results in visual artifacts, such as
      jumpy or grainy video.
                                          48/46




MIDI
 For users that are capable of playing
  musical instruments such a keyboards
  • Notes + instrument
 Sound Forge can be used to capture
  information – see Sound Forge Power !
  Book by Scott R. Garrigus
                                                           49/46




Cool Effects
   Changing Sample Rate and Bit Depth
   Echo
    • Repeat sounds that mimic an initial sound
        –   Simple delay – 0.001 to 5 seconds
        –   Multi-tap delay – many simple delays at once
        –   Chorus
        –   Flange
   Pitch
    • Bend
    • Shift
   Volume
    • Amplitude Modulation
    • Distortation
                                                50/46




Changing Sample Rate and Bit Depth

http://advance.engj.ulst.ac.uk/multimedia/data/so
  undmultimedia_soundforge/06_FileAtts/6_02/s
  nd_sf7_034b.pdf?
 If you selected a higher sample rate e.g. 48,000
  you will have noticed that the pitch was higher
  and the duration was shorter.
 If you selected a sample rate of 8,000 the pitch
  would have been lower and the duration longer.
                                           51/46




Changing Sample Rate and Bit Depth

 To maximize storage space larger sound
 files (24 and 16 bit) are frequently
 converted to smaller (16 and 18 bit).
               52/46




Simple Delay
                  53/46




Multi-tap Delay
                            54/46




Chorus
 Produces a fuller sound
                                        55/46




Flange
 Produces a spacey, whoosh or warble
 sound
              56/46




Pitch -Bend
                                          57/46




Pitch - Shift
 When the pitch is raised (lowered) it
  shortens (lengthens) the data

 Shift stops this
  side effect
                        58/46




Amplitude Modulation
 Modifies the volume
                             59/46




Distortion
 Allows user to add noise
                                                    60/46




Sound Compression
http://advance.engj.ulst.ac.uk/multime
   dia/data/soundmultimedia_soundfo
   rge/06_FileAtts/6_05/snd_sf7_037b.
   pdf?
 Understand the difference between
    • Lossy
        – typically discarding data that is
          calculated to be inaudible to the human
          ear.
    • lossless
        – all the fidelity of the original source
   Identify the MP3 file format
   Examples of uncompressed audio
    files
    • WAV, AU, and AIFF.
                                               61/46




Adjusting the Volume
 The Volume Function
  • Increase / Decrease the amplitude of the
    selected data or the entire file
     – Process > Volume

     Too high and
     clipping can occur
                        62/46




Fades
 Fade-in
  • Process > Fade-in
                         63/46




Fades
 Fade-out
  • Process > Fade-out
                        64/46




Graphic Fades
   Process > Graphic



Envelope Points
                                                            65/46




Normalise
   Process > Normalize
    • Will remove clipping effect by checking the highest
      amplitude first




    Can normalise between two separate tracks
                       66/46




Graphic Fade Results
                                      67/46




Equalisation (EQ)
 Ability to adjust Treble and Bass
 Process >

				
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