Digital Audio for Multimedia         Using SoundEffects & SoundHack As we have become more sophisticated in our media use, so too have we become less tolerant of "poor" quality media. This is quite evident in the use of sound in multimedia. In the beginning, any sound at all was "cool!" Now, however, we demand more. With the proper computer hardware and software, you can capture, edit, or create any type of sound -- but it takes practice to do it well! Therefore, in this exercise students will use two shareware programs to experiment with digital audio and practice recording and editing an audio file and then make it playable over the World Wide Web. Specifically, this week students will: Log-on to the Social Science Mac Lab Computers Review information on Digital Audio for Multimedia Learn how to use SoundEffects to edit jumbled-up sound files Record a custom greeting for a webpage Learn how to use SoundHack to change audio file formats Complete these tasks before the end of lab Finally, don't forget to Log-out! Digital Audio for Multimedia Click Me! When studying digital audio and its applications, it is important to understand how digital audio recording and playback is fundamentally different from analog technology. Before digital technology, audio was recorded by capturing an analog signal and reproducing the sound wave generated by the original source electromagnetically. However, whereas such recordings are "analogous" to the original, they always differ slightly from the original. Furthermore, each copy of a copy is called a generation -- successive generations result in the deterioration of the signal and consequently, the quality of the sound decreases dramatically. In analog-to-digital conversion, the analog signal is measured [sampled] as certain intervals [frequency]. A digital code is created and stored in sequence to become a digital representation of that electronic signal. Upon playback, the digital file is fed into a digital-to-analog converter that reproduces the original analog signal. In digital audio formats, multiple copies can be made without the deterioration of signal found in analog formats. The quality of sound at the final audio stage is dependent upon how many samples were taken during the original digital conversion -- the more samples taken, the more accurate the representation of the electronic signal, but consequently, the larger the storage space needed for the digital file. In multimedia development, a trade-off between sound quality and file size has always been at the heart of digital audio. This compromise has influenced decisions on both how digital audio will be used as well as how standards for digital audio will be established for multimedia and Internet applications. One alternative to digitally "sampled" audio is MIDI, Musical Instrument Digital Interface, which enables people to use multimedia computers and electronic musical instruments to create, enjoy and learn about music. There are actually three components to MIDI; the communications Protocol [language], the Connector [hardware interface] and a distribution format called Standard MIDI Files. One reason for the increasing popularity of MIDI use in multimedia is that, unlike digital audio files [.wav, .aiff, etc.], a MIDI file does not need to capture and store actual sounds. Instead, the MIDI file can be just a list of events which describe the specific steps that a soundcard or other playback device must take to generate certain sounds. Therefore, MIDI files are much smaller than digital audio files. Furthermore, the events are also editable, allowing the music to be rearranged, edited, even composed interactively, if desired. Also, just about every personal computer is now equipped to play Standard MIDI files. As a result, MIDI has become the primary source of music in many popular PC games and CD-ROM entertainment titles. Likewise, thousands of MIDI files are available on the Internet for recreational use. Obviously, how sounds are used in multimedia productions will vary greatly. As with other elements of multimedia preparation, sound deserves careful consideration as to the method and location of its use. It is also important that your sound files be interwoven into the production of your multimedia project [just as important as images or layout & design] in order for the sounds to appear to be a part of a coherent message -- the coordination of sound files and any associated graphics, therefore, becomes extremely important. Audio streaming has become an increasingly popular way to get large audio files [and video files for that matter] to play smoothly over the Internet while the files continue to download to your local computer. The pioneers in this endeavor have been the folks at RealNetworks. RealNetworks offered free software that not only compressed but streamed media files on its own proprietary player [at first, only audio but later they added video]. After several years, RealMedia works quite well and has a majority of the market; more people have downloaded the RealMedia Player helper application than any of its competitors. Of course, like many other aspects of multimedia, study closely and learn from successful titles &/or websites -- But, don't let the "technicalities" of how they do things stiffle your creativity! For more information on digital audio, MIDI & Audio Streaming be sure to visit the following sites: Audio & MIDI FAQ by Silicon Graphics Audio File Formats FAQ1 & FAQ2 regularly compiled by Guido van Rossum [Hosted in the Netherlands] The World Wide Web Virtual Library: Audio maintained by Jonathan Bowen [Hosted in the UK]. Index of EQ Magazine Columns authored by Roger Nichols. WebMonkey's Audio for the Masses MIDI Manufacturers Association's Help with MIDI Harmony Central's MIDI Tools & Resources RealNetwork's DevZone Library for Streaming Media Using SoundEffects 0.9.2 SoundEffects is a relatively powerful shareware sound editing program originally developed by Alberto Ricci. Even though SoundEffects is no longer being supported by RicciSoft, SoundEffect's strength still resides in its ability to apply many digital effects to recorded sounds. Not only can SoundEffects change sounds in many ways through its variety of effects, but it can also handle multi-channel sounds, sampled at any rate up to 64kHz and with any sample size between 1 and 32 bits. Recording rate and sample size are only limited by your Mac or your sound input device! SoundEffects document windows are divided into three parts [see image below]: the top part contains information about the sound, such as its sample rate, number of channels, and size. the middle part is where all the editing takes place: you can select portions of the waveform with the mouse or with the arrow keys and then cut, copy, paste, apply effects and so on. at the bottom there are various buttons, much like in a tape recorder. You can record a sound, play the sound and control the sound that is playing. NOTE: This is a Beta version of software that went commercial under another name [SoundMaker by MicroMat]. As such, there is No Undo [otherwise, it's very stable!]. If you make a mistake or do not like what you did you need to select Revert from the File menu. Revert will open up the last saved version of the file you are working on. Therefore, when you complete a step that you like be sure to save your work! Don't be intimidated by the startup windows, SoundEffects is really quite easy to use. Basically, if you know how to cut and paste in a word processor then you can use SoundEffects. When you open up a sound in SoundEffects you should see a window similar to the following: What you see is a "scatter plot" or a graphical representation of the sound file. Using the various Zoom buttons you can zoom in or out of the scatter plot or fit it into the window. The six buttons on the bottom should all be familiar to you. From left to right they are: Record, Stop, Pause, Play, Fast Forward, and Repeat or Loop. When you hit Play, SoundEffects will play the entire sound from the beginning. To listen to a portion of the soundwave you need to select it first and then press Play. Making & Moving Selections Making selections is much like selecting words from a sentence in a word processor. To select a portion of the scatter plot simply move your cursor into the scatter plot, click and drag your selection to however long you want it. Zooming in can help you make more precise selections. To delete a highlighted selection simply hit the Delete key. To move the selected portion to another area you need to select Cut from the Edit Menu [Command-X on the Keyboard]. Then click once in the area you want to move it to, make sure there is an Insertion Cursor visible. Again you can zoom in to make your placement more accurate. Once your insertion cursor is in place, select Paste from the Edit Menu [Command-V on the keyboard]. Viola! You have just moved the selected area. Recording Digital Audio Before you record your own "welcome" message for your lab assignment, go first to the Preferences -->Recording-Sound Input Device option found under the File menu and change the settings so that it will look similar to the following: To record a new sound, select the "Record..." option from the "Sound"menu, this should open a new sound window [in the background] and present you with the "Record" options box. Prior to beginning your recording, you should open the "Monitors & Sound" Control Panel [selected from the Apple Menu]; click on the "Sound" button and then make sure that the "Sound Monitoring Source" option reads "Sound In" [see below]; this will insure that your microphone is "live." When finished with the initial setup, you can turn your attention to the "Record" options box and begin recording, pause or stop recording, play the recorded sound or choose options for recording. Inside the recording window a small waveform shows what is coming through the microphone. The wave is red when it is being recorded, otherwise it is green. When you are done, click on the "Stop" button, then click on "Save." If, on the other hand, you do not want keep the recorded audio, simply click on the "Cancel" button and try again. Clicking on "Save" in this dialog box will not actually save you file, however. Your recorded sound will simply appear as a scatter plot of your sampled audio in the sound window [formerly in the background]. You can now edit your sound file just like you did earlier. If you want to apply any effects you need to select that portion of your sound file to which you wish to apply the effect. Because there is no Undo, it is wise to first save your sound file before beginning any editing. Applying Effects To apply effects to sounds, select the portion of the sound you wish to modify [if you don't select anything, the whole sound will be used], then choose an effect from the "Effects" menu. If the effect you chose has a settings dialog, it will be shown, otherwise the effect will run immediately. If you choose an effect from the "Effects" menu while holding down the shift key, a window will be displayed containing information and help about the effect. When you have finished playing with your file and getting it "just right," you should save your sound file as a Macintosh AIFF file. Name your file "Lastname_welcome.aiff" using the "Save As..." option under the "File" menu selection. You will change your audio file to a web-playable format in the following section. Using SoundHack 0.868 SoundHack performs various sound file manipulations that have been previously unavailable on the Macintosh. SoundHack includes sound file type conversion, spectral extraction, spectral mutation, spectral dynamics processing, a varispeed/sample rate converter, sound file convolution, ring modulation, the phase vocoder, a binaural filter and an amplitude analysis and gain change module. Don't worry if you do not understand much of the above description, we will be using SoundHack primarily for converting our sound files from one format into another. To convert our sound files, select Open from the File menu and open up your Greeting sound file. Now choose "Save a Copy..." from the "File" menu. Change the File Type and Format to match the example and click "OK." Tasks You Must Complete . . . First of all, you will need to download and uncompress the sound files used in this lab exercise. The compressed file [sound_exercise.sit.hqx] is located in the "lab_09" sub-directory in the "summer_2000" directory on the "www.soc.hawaii.edu" server. If Stuffit Expander does not automatically uncompress the downloaded file, you will need to launch in manually. Once the file is uncompressed, a folder should exist in your Guest directory by the name of "Sound Exercise." Using SoundEffects open and fix either "WorkToDo_mixed.aiff" or "ThatsAllFolks_mixed.aiff". The order of the words have been moved around. Extra words and/or sounds, as well as sections of silence have been added. Your objective is to put the words back in order and delete the extra words and/or sounds. You can use the "final" versions as a reference to hear how your file should sound when completed. REMEMBER!! SoundEffects does not have an Undo feature. You will need to use the Revert function to undo any undesired changes. So be sure to save your work everytime you do something you are satisfied with. When you are done, save your work in its finally version and be sure to add your last name as replacement for "mixed" in the filename [as in, "WorkToDo_Lastname.aiff" or "ThatsAllFolks_Lastname.aiff"]. Next, you will need a microphone to record a personalized greeting to attach to your own web page [instructor will provide -- be sure & return it when you're finished]. Once a microphone is connected to your computer follow the steps listed in the recording audio section above to record your greeting. You can say something simple like "Hi, my name is (name), welcome to my home page." Once you have recorded your greeting, add a fade in and a fade out at the ends. Feel free to add any other effects you want, just don't go overboard! When you are done, save it as an AIFF file and name it "Name_welcome.AIFF" Using SoundHack, convert your greeting in to a Sun(.au) file following the steps mentioned above. Name your file "Name_welcome.au" If you wish, use Dreamweaver to add a link to your greeting in your extra credit "bio.html" file [assuming you have built such a file by now!]. Using Fetch upload your edited "bio.html" and your greeting file to your "public_html" directory in your Uhunix account. Remember to select Raw Data as the format when uploading your greeting sound file. As you'll no doubt remember, your "bio.html" file should be uploaded as a plain text file. Last, but not least, upload your fixed sound file(s) and your converted greeting to the "all_pau" sub-directory under the "summer_2000" directory on the "www.soc.hawaii.edu" server so that I can give you credit for completing this Lab!   [ Syllabus ][ Lab Assignments ][ Downloadable Resources ][ Back to Home ]   Copyright © 1999-2000   By: M. R. Ogden -- ogden@hawaii.edu   (Rev. 19 June 2000)