Objectives

• Learn how to manipulate music and sound in a desktop audio editing environment.
• Experiment with various editing techniques for digital audio including copy, paste, and cropping; fade in and fade out; amplitude and envelope alterations; reverb and echo; and others.
• Record digital audio from a live or prerecorded source.
• Add additional tracks to a digital audio clip.
• Learn how to convert a variety of digital audio file types.

Directions

1. Read through the hands-on tutorial to gain an overview of the process
2. Follow the hands-on tutorial, step-by-step, to experiment with various prerecorded music and sound clips
3. Digitally record some live music and/or sound on your own
4. Use the Worksheet for Project 15 (see below) to record your work.
5. Submit the completed Worksheet with the Evaluation Form for Viewport VII

Software

• The Worksheet for Project 15 is an Adobe Acrobat file. From the Acrobat reader you can print out copies of the form.

 
• Click here to view the Worksheet form directly from those Web browsers that will automatically display Acrobat files (e.g., Netscape, Microsoft Internet Explorer, NCSA Mosaic browsers).

 
• For those Web browsers that will not display Acrobat files (e.g., I-View HTML Viewer) download the Project 4 Worksheet to your hard disk. Then drag the file onto the icon of the Acrobat reader application.

 
• Sound Forge XP Demo. You will need a digital audio software package like Sonic Foundry's Sound Forge XP. The project below is tailored to Sound Forge XP 4.5. We suggest you use the demo version of Sound Forge provided on the EMT CD-ROM disk just for practicing the exercises in the workbook (this version will not allow saving your work). Then, when you are ready to create your own digital sounds and music clips, use a full-working version of Sound Forge, or whatever comparable software you have available.


Caution: There are several limitations on the Sound Forge demo version. The most critical one is that it will quit every 15 minutes and you will need to restart Sound Forge.
 

• Guidesheet files. A folder of files especially prepared for Project 15 is available on the EMT CD-ROM disk. You will need these to complete the activities below.

Introduction

Project 15 is designed to show you how software like Sound Forge XP can be used for desktop digital audio editing (DTP) to produce a wide variety of digital speech, sound effect, and music clips. Sound Forge XP will let you record, edit, and transform digital audio in many very sophisticated ways with very little effort on your part.

If you have not done so, take time to read the modules in Viewport VII on music sampling and digital audio. The data concepts in Module 25 (and earlier in Module 10) will be very helpful for you especially for terminology.

We have provided a folder of short digital audio clips. Look at the files in the "sndproj" folder shown below. Notice the extensions on the files. These are all different file types for audio and audio compression.

Here briefly is the application of each audio file type:

wav	DOS or Windows sound files
aif	Audio Interchange File Format (AIFF)
au	ULAW sound format commonly used across the Internet - (pronounced 'mu-law' audio files as the U is really the Greek mu)

Sound Forge, like many good sound editing software, will read and convert many different files types.
Let's begin. There are six steps to the tutorial on the use of Sound Forge.

Steps:

1. Finding Your Way Around Sound Forge
2. Copying, Pasting, and Cropping a Digital Audio Clip
3. Fades, Amplitude, and Envelope Editing of Digital Audio
4. Combining Audio Clips by Manipulating Tracks
5. Reverb, Echo, Equalizing, and other Digital Audio Goodies
6. Recording Your Own Digital Audio Clips

Return to the project menu

Step 1: Finding Your Way Around Sound Forge

Take a look at the Sound Forge window below:

• Using either the demo version of Sound Forge XP provided with the EMT CD or a full-working version of your own, load the file "purplepg.aif" in the folder "sndproj" with Sound Forge. You can either double click on the purplepg.aif file (in Windows 95), or Run Sound Forge (Windows 3.1) and select Open from the File menu and then select the "purplepg.aif" file. You will need to select "All Types (*.*)" or "Macintosh AIFF (*.aif, *.snd)" from the "List of File Types:" menu in the Open file dialog box.  (Hint:  If you have the Auto Play box checked, Sound Forge will automatically preview the file for you when it is highlighted.  Plus it will display any information it can tell from the file in the bottom half of the Open file dialog box.)


When done, your screen should look something close to the one shown in the figure below.

• Let's look around the screen to get our bearings. Using the figure above as a guide, look for the menubar and the toolbar at the very top. The toolbar has two rows of graphic icons that replicate many of the commands accessible from the menubar. Find the main Audio Edit window for the sound file your are working on (the purplepg.gif file for our example). This is the window with the a blue graphic of the amplitude envelope of the sound sample and is labeled "PURPLEPG.AIF".

 
• Find the Player Controls, they are in two places: on the second row of the toolbar and at the bottom left-hand corner of the Audio Edit window. These serve the same function as the controls on a tape recorder. You can play, stop, pause, record, and loop the sound clip in the Audio Edit window.

 
• Find the Zoom controls in the lower right-hand and left-hand corners of the Audio Edit window; the small and large magnifying glass for Zoom In and Zoom Out. Try clicking on the two icons to see what affect they have on the display of your sound clip in the Audio Edit window. The lower right-hand glasses control the horizontal time element: how much of the sound clip you will see on the screen and the amount of detail you will see. To change the vertical dimension (Level), the height of the sound wave, just click on the magnifying glasses in the left-hand corner of the Audio Edit window. Set the zoom controls so your Audio Edit window looks similar to the figure above.

Before we start messing around with this sound clip, we will examine one other feature of Sound Forge. Go to File => Properties.  When the new window appears, click on the Format Tab as shown below.
 

This dialog box gives you some key information about this sound clip. The sampling rate is 8 kHz and the sample size is 16 bits. The sampling rate could also have been 8 kHz, 11 kHz, 22 kHz, or 44 kHz. The sample size could also have been 8 bits. What rate and size you select is always a trade off between the quality of the audio you want and the size of the audio file. See Module 25 in the EMT textbook for more information on this.

(Note that the "Summary" tab is grayed out.  The summary tab allows you to annotate or more importantly "Watermark" your sound file.  You can place vital information such as copyright info, engineer info etc...  Unfortunately, this is only available with Microsoft PCM *.WAV formats.)

Check yourself off on the Project 15 Worksheet when you have completed all of the work for Step 1

Return to the project menu

Step 2: Copying, Pasting, and Cropping a Digital Audio Clip

It is time to start experimenting with the toolbar and the features of a sound editing program like Sound Forge XP. The sound clip that you currently have loaded into Sound Forge is a clip from a recording of Northwestern University's Marching Band (purplepg.aif).

Place the mouse cursor anywhere over the graphic representation of the sound clip.  You will notice that the cursor now changes to an "I - beam" tool.  Click and drag over any section of the clip to select a smaller portion of the sound file.  Now, take a close look at the transport buttons above and below the sound clip.  The upper and lower bars have similar but different functions.  The upper transport controls are for more global control of the sound file, while the lower controls are more specific to the sound file.

Upper Controls

The button functions are described from left to right:
 

Lower Controls

Experiment with the transport toolbars to see for yourself how they work.    When you feel you have a good idea of their functions and how to play selections from a larger sound clip, make sure you have the file "purplepg.aif" open and proceed to the tutorial below.

• Take your mouse and click-and-drag over the area highlighted as in the figure above.   (We want to crop the sound clip so that we have only the phrase in the middle.)

 
• Click on the Play button and listen to the playback of the selected area. Does it sound okay? Or, do you need to fine tune it by selecting a little earlier or later of the selection?

 
• Hint: Slowly bring your cursor to either end of the highlighted area.  You will notice that the cursor turns to an arrow pointing left and right.  If you click and drag at this point, you can extend or shorten the length of the selection allowing for fine tuning the exact points of the sample.  On the other hand, if you click outside of the selected area the selection is erased and you are forced to start over again.  (This may be good if the selection is completely wrong!  Experiment with this along with playing the selection until you are comfortable that you have the phrase properly selected.

 
• Once you are satisfied with your selection click on the Crop button in the Toolbar. 

Or, select Crop from the Edit menu. Portions of the sound clip before and after the highlight area should disappear leaving only the selection you want.

The resulting Audio Edit window should look something like this:

 
• Play the clip.

 
• Let's try copying and pasting the waveform. Select the entire sound clip. You can double-click inside of the waveform or pick Select All from the Edit menu. Click on the Copy icon in the toolbar or select Copy from the Edit menu. 

 
• We are now going to paste the audio clip at the end of the current selection. This will repeat the the audio clip. Click with the mouse at the end of the current selection as shown on the screen above. Then select the Paste button in the toolbar (to the right of the Copy button).


Position the mouse at the end of this sound clip (or hit the Go to End button) and paste it again. The end result should look like the figure below.

• Let's save our work. Select Save As (not Save) under the File menu so we can save our new version of the work. Change the file format in the "File Save Type:" to "Wave (Microsoft) (*.wav)" and the extension to the file name so it reads "purplepg.wav". See the figure below.

 

If you were to click on the Summary button right now you would be able to "Watermark" your sound file. Before saving your work click on the Summary button to preview what you could do with this option.


 
• To remove a portion of a sound from an audio clip, just select an area of the sound and choose the Cut or Clear option from the Edit menu (or Cut button on the toolbar). The Cut option places the clip in the clipboard so you can paste it somewhere else. The Clear option just erases it completely. Try the Cut and Clear options on the purplepg.wav sound sample.

 
• Try copy and pasting from two different sound files. You can open the "salsaton.aif" file in a second window in Sound Forge. Copy a brief clip from this drum routine in the "salsaton" window, click on the "purplepg.snd" window, and paste in the sound at the beginning of the clip. (Thanks to the drum line of the Northwestern University band for this clip from their Internet web page.)

Check yourself off on the Project 15 Worksheet when you have completed all of the work for Step 2

Return to the project menu

Step 3: Fades, Amplitude, and Envelope Editing of Digital Audio

For this step let's begin to explore many of the powerful tools that sound editing software provide. We will load the "salsaton.aif" file from the "sndproj" folder and experiment with tools that let you control amplitude.

• Load the "salsaton.aif" file into Sound Forge. Adjust the zoom until your screen looks like the one below.


• Look at the General/Format option tabs under the Properties menu to see that this sound sample was recorded at a 8 kHz sampling rate, with an 16-bit sample size.

• Play the sound sample.

 
• Let's try the Fade option to produce a fade in and a fade out. We can simulate the drums gradually fading in and then fading away as if they were passing us in a street parade (in fast motion!). Examine the figure below. Select the black portion of the sound sample which has been highlighted and then select the Fade option under the Process menu. When you select the Fade option, another menu will pop-up off to the side showing three more options: Graphic, In, and Out. Pick "Fade In" for now.




When you select the Fade In option it will automatically adjust the amplitude from the beginning to the end of the selection area you have marked in the sound sample.  The computer will now process the sound sample and reduce the amplitude of the selection starting very low at the beginning and ending with no change. When it is done the display should look like the one below.


 

• Play the sound sample now and hear the effect.


Do the same thing to create a Fade Out starting about two-thirds of the way through the sound sample (where the cursor is positioned below) and continuing to the end of the sample. The Fade Out option is right under the Fade In option in the Process menu. Your result should look like the graph below. Play the sound sample and listen.



When done with this step, close the window and load the original SALSATON.AIF file again. This will bring back the original "salsaton.aif" file without any of the fade effects. If you want to save the fade effects, then first select Save As and give the file a different file name.
 

• Two other amplitude techniques are changing the overall amplitude and altering the sound envelope. Let's say we need to reduce the amplitude of the entire sound sample to make it soft for background music.


From the Edit menu choose Select All (or double-click inside of the Audio Edit window). Then select the Volume option from the Process menu. When the dialog box is displayed (see below), set the amplitude to 30% and click on the OK button. When the processing is completed, you should visually see the difference in your graphic. Select the Play button and listen to the result.
 

HINT:  If you place a check mark next to the "Create Undo" you will be able to "Undo" the transformations to the sound file in case you don't like them. Furthermore, an important feature in Sound Forge XP 4.5 is the ability to have a list of multiple "Undo"

• You can use the same process to increase the amplitude of a sound. If something was recorded too low, set the amplitude to a percentage higher than 100%, for example, 200%.

 
• Let's try creating an envelope effect next. Do an Undo from the Edit menu to revert back to the previous "salsaton.aif" file (or reload the original file). We can create the effect of the sound of the drum line fading quickly in and out with an envelope effect using the Fade option from the Process menu.




Select all of the sound sample (double-click in the Audio Edit window). Under the Process menu go down until you can select the Fade option, then select Fade Graphic from the pop-up menu. A large dialog box will appear with a graph representing the selection you made from the sound sample. There is a straight line across the top with handles on it. With your mouse, click on a point (open square box) on the line and pull it down to shape the envelope. If you find that you need to add a point, click on the line and a new box will appear.  Make your graph look like the one above. When you are done, click on the OK button in the upper, right-hand corner to process the sound.



Play the clip and hear the effect. Go back and experiment with some other envelope shapes as well.
 

• That concludes this step which has introduced you to fade, envelope, and amplitude effects in sound sampling software. Use Save As from the File menu to save a version of the file which you have modified using the techniques learned in this step.

Check yourself off on the Project 15 Worksheet when you have completed all of the work for Step 3.

Return to the project menu

Step 4: Combining Audio Clips by Manipulating Tracks

We will now show you how to work with tracks in a sound sampling program. In Sound Forge, you can edit and manipulate audio information in the two channels of a stereo recording as if they were two tracks. In the "sndprog" folder there are two files: "waterfal.wav" is a penny whistle recording and "voice.wave" is a recording of spoken voice made on the computer with a microphone. Both recordings are WAVE files meaning they were recorded on a Windows/PC computer.

• Your task is to import the "voice.wave" file as a second track (or channel) to the "waterfal.wav" file. To do this we will need to convert the Waterfal file to stereo and then bring the Voice file in on the right track or channel. The finished effect we are looking for is shown in the Audio Edit window below.

Follow along:

• Open the waterfal.wav file from Sound Forge. Be sure to change your Files of Type setting in the Open dialog box to show WAVE files.


Next we want to convert the Waterfal file to stereo. Choose Properties from the File menu. Notice that it is a Mono (1-channel) file. Click on Stereo and when the next dialog box appears, select Left Channel, then OK. Your Audio Edit window should look like the top of the window shown above; adjust the zoom controls if need be.
 

• Now to bring the Voice file in and place it in the Right Channel. Open the voice.wav file. It will appear in a new window by itself. (You now have two windows open, one for Waterfal and one for Voice.) This file needs to be cropped to get rid of extra space and some sound glitches. Select the portion shown below, then use the Crop option from the Edit menu.



 

• Now to merge the VOICE sound with the WATERFAL file. Do a Select All from the Edit menu, and then a Copy. Now, go back to the WATERFAL window and click with the "I Beam" tool approximately at the point you wish the voice to begin.   (Make sure to click in the open Right Channel!) Go to Edit => Paste Special and then select Mix. When asked, click on the Right Channel option. You should now have both files merged into one stereo file for WATERFAL. (You can close the VOICE file now, you are done with it. You can also save the WATERFAL file under a new name, like "WATERVOC.WAV".)

 
• Your window should look like the WATERFAL.WAV one above when done if everything went okay.

 
• Play the sound sample. To get both tracks to play together, click in the far left-hand corner of the upper track, hold the Shift key down, and click in the far right-hand corner of the lower track. Then press the Play button in the Control window.

Hint: Drag the cursor over the two tracks of the WATERFAL file. It is an I-beam cursor. Notice how it will add an L next to the I-beam or an R when the cursor is over the Left or Right track. To select only a single track for playing or editing, move the cursor until it has an R or L and then click in the track.

• The last step is to save your work as a Real Audio file with an extension of ".ra" on the end of the file name. We will save this file in this new format that can be played by most computers on the Internet.  This does depend on whether or not the receiving computer has Real Audio installed and configured correctly on their computer.  Real Audio files have a proprietary file format and compression rate and for the most part are not changed by the file creator.  Sound Forge XP 4.5 will do this automatically.

 
• To do this, choose Save As from the file menu and a new window will pop up allowing you to choose between which formats to save your file as.




Select the RealMedia option from the "Save as type" bar.  You will notice that the Format and Attributes options are grayed out.  As stated before, these are "set" by Sound Forge and are not user changeable.
 

Step 4a:  Further Uses for the Mix Paste Option

Follow the steps above, however, this time do not place the wave files in separate L/R Stereo Channels.  You can use Mix Paste to paste one file over another.  For clarity, the steps are outlined below.
 
• Open the "Waterfal.wav" file.  (no need to expand to stereo this time)
• Open the "voice.wav" file, crop, and then copy the cropped file.
• Place the "I-Beam" tool approximately where you wish the voice.wav to begin.
• Select Mix from the Paste Special option in the Edit menu.

The Mix Paste window will appear allowing you to configure the volumes of both sound files.  If you need to configure them and hit OK.

HINT"  If you have the check mark placed next to the Apply destination volume to overlapping area only, the volume changes will apply to the paste area ONLY!  Otherwise, the volume changes will apply to the entire file.
 
• Review the changes and save your work!

 

Check yourself off on the Project 15 Worksheet when you have completed all of the work for Step 4

Return to the project menu

Step 5: Reverb, Echo, Equalizing, and other Digital Audio Goodies

In Step 5, we will experiment with some of the other special effects.

Load in the original waterfal.wav sound file for your experimentation.

• Reverb. Reverb adds depth to your sound by simulating acoustical reflections within a room. To try this effect, select all or part of the waterfal.wav sound sample, then under the Effects menu, choose Reverb. A dialog box will appear as shown below. Pick Medium Room and try it. Then do an Undo from the Edit menu and return to Reverb to try other settings. (Check the Create Undo so you can undo each effect and try again.)  Sound Forge XP does not allow for configurable Reverb settings.  The options below are "pre-set."



 

• Echo works much the same way as Reverb. Try it. Try the settings shown below first. Then with an Undo from the Edit menu, try other settings until you get a feel for the controls.



 

• Equalizer. The equalizer lets you selectively alter the amplitude of a specific band on frequencies within a sound sample. You'd use the equalizer if you wanted to reduce too much bass sound, too much high frequency sound, or to eliminate some high frequency sound. Select Graphic EQ under the Process menu.



In the Equalizer dialog box above, we have reduced some of the low frequencies, boosted some midrange frequencies, especially the highs above 5 kHz. Experiment with different settings on the Penny Whistle clip. Use the Undo under the Edit menu to reset a change and then try again.
 

• Experiment with others. Be brave now! Experiment with other effects to see what they do to the sound sample: flanger, bender, tempo, etc.

 
• Use a variety of the special effects to produce your own bizarre version of the Penny Whistle tune. Be sure to save your work when done, and under a new file name.

Check yourself off on the Project 4 Worksheet when you have completed all of the work for Step 4

Return to the project menu

Steps 6: Recording Your Own Digital Audio Clips

One powerful feature of digital audio editing software is the ability to record your own sounds, voice, and music. To do this from Sound Forge XP you will need to connect either a tape recorder with recorded music or a microphone to the computer through the PC's sound card. How to do this varies widely from PC to PC. Check your computer user manual for more instructions as well as the Sound Forge Help built into the software. We will cover recording from CD audio discs in the next Guidebook project, Project 16.

To record a sound clip in Sound Forge:

• Make sure your PC and Sound Card are configured correctly (Check the Appendix Help files for Windows Sound Setup and Configuring Windows Drivers)
• Click the Record button found in the upper transport controls.
• If need be, you can change the Recording Attributes by using the New button.  (44.1 kHz, 16 Bit, Stereo etc...)

When you click on "New" in the previous window, this window will appear allowing you to configure the defaults of the sound file you are about to record.  When you are finished making the changes click "OK" to get back into the record window.

To start recording, press the Record button on the dialog box shown above to activate the recording process. Check the Monitor Input if you want to see some recording levels.  (To monitor the levels that you are about to record, check the box next to the "Monitor" LED's.)

Be careful, digital samples can take up lots of memory!

Record several sound samples of your own. Try different formats. Be sure to use all of the editing skills you acquired earlier in the project activities to edit and enhance your recording. Crop the file, adjust the amplitude, add a little reverb, etc.
 

Check yourself off on the Project 4 Worksheet when you have completed all of the work for Step 6

Return to the project menu

Happy Sampling.....!

Version 1.0
©1996 David B. Williams and Peter R. Webster
Schirmer Books