Tricks of the Game Programming Gurus

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BLASTER Master Tutorial NOTE: The SAMPLE1.VOC example file is not included with the shareware version. Substitute any VOC file. The future of sound recording is digital. Digital recording, also known as sampling, uses a system of numbers to represent the sounds recorded. Because the sound is stored as numbers, the quality of the recording never changes. Unlike analog recordings like tape and vinyl records that lose fidelity each time a copy is made or the record is played, a digital recording will always sound the same. With the release of the Sound Blaster, PC users can explore the world of digital recording. Another big advantage of digital recording is that sounds can be easily edited and manipulated mathematically. Usually when a digital recording is made, there are segments at the beginning and ending of the file that need to be trimmed away. If you are recording speech, there will be "ugh" sounds and long pauses that you will want to remove. Your digital file will be smaller and sound more professional by using these simple editing functions. This is where BLASTER Master comes in. BLASTER Master is a shareware program for editing sound files. It is graphically based and has a very elegant and intuitive user interface. But do not let the simplicity of the user interface fool you. BLASTER Master is one of the most powerful tools for manipulating digital files available. All the basic editing functions are included. Segments of the sound file can be removed, saved, moved, copied and more. In addition to these basic block functions, BLASTER Master also includes a tool kit of advanced digital signal processes (DSP) for altering your sound files in ways that are nothing short of amazing! With a little practice and experimentation, you will be able to combine the many functions in BLASTER Master to create sounds you never dreamed were possible. This is a short tutorial on using BLASTER Master. We will cover some basic editing and also have some fun too! Here is a list of some of the features we will explore. * Echoing files with different delays and echo volumes to achieve a variety of effects. * Reversing files to see what they sound like backwards. * Changing the pitch so your voice sounds like either a Munchkin or a giant. * Adjusting the volume of sound files * Fading the volume at the beginning and end for very professional sounding results. * Mixing sound files together to make a combined file just like a multitrack recorder. * Looping segments of sound files for some really cool Rap DJ effects. These are only a few of the processes we will explore. Don't worry if you don't understand some of the features. By the time this tutorial is completed, you will be well on your way to becoming a Sound Blaster Master! GETTING BLASTER MASTER UP AND RUNNING This tutorial assumes that you have already correctly installed BLASTER Master. Here are a few tips for getting the most from the software: You will need at least an 80286 based IBM PC compatible. Sound processing requires alot of computer system resources. The faster your computer runs and the faster your hard drive reads and writes the better. Since most of the DSP functions require thousands, if not millions, of calculations, a math co-processor is very handy, but not required. 80486 DX processors have a math co-processor built in, so these CPUs naturally work quite well. You will also need a high resolution EGA or standard VGA graphics system to run the software. BLASTER Master visually plots the wave form to make editing easier and quicker. If you want to edit individual segments of the file for cut and paste type operations, you will need a Microsoft compatible mouse. You will also need alot of free 640k memory. Since BLASTER Master is a large program capable of working with very large files, I recommend a minium of 560k free memory. You might could get by with slightly less, but some of the functions might not be able to work correctly. Most PCs sold today come with at least two megabytes of memory. We are only concerned with how much 640k DOS memory is free. That's what counts for running programs. Last but certainly not least, I recommend you have plenty of free space on your hard drive. Even though the unregistered shareware version of BLASTER Master will only process files no larger than 25 seconds in length, you can quickly use up several megabytes of disk space. A 25 second stereo file sampled at 22khz uses about 1.2 megabytes of disk space! A WORD ABOUT SHAREWARE BLASTER Master is a shareware program. In other words, it is released in a form that may be shared with others. It is not public domain. It is a copyrighted program and subject to the same legal protection as all copyrighted works. BLASTER Master can be found on BBS's and online services like GEnie, CompuServe and America Online. Unlike most shareware, you are not limited to only 30 days of use. You may use the unregistered version of BLASTER Master for as long as you like. I hope you enjoy it! I do this because many of my BLASTER Master users are students and coming up with even a paltry sum of $29.95 is very hard. If you are able to pay for the software, then I would appreciate your support. When you register BLASTER Master, I send you a code number to remove the 25 second editing limitation. This number works on all versions of BLASTER Master. Not only do you get unlimited use for the version you currently have, you will also have unlimited use with the frequent updates of the software. As long as people continue to support BLASTER Master financially, I will continue to produce updates. A QUICK TOUR THROUGH BLASTER MASTER We are ready now to learn how to navigate through the functions and dialog boxes of the program. As stated earlier, I strongly recommend the use of a mouse. In most cases, you will only need your keyboard for entering a few function parameters and entering file names. If you should be using your keyboard, you can advance through the dialog boxes using the TAB key. The TAB key combined with the SHIFT key moves in the reverse direction. You will also find the arrow keys and the PgUp, PgDn, Home and End to be very useful. STARTING BLASTER MASTER From the DOS prompt, type: C:>BMASTER [ENTER] The program will clear the screen and begin "looking" for your Sound Blaster. If everything is as it should be, you will see a light blue graphic screen with the BLASTER Master logo and a large dark blue dialog box titled, "Select Sound File". This is the opening screen and where we will select our sound files from. The top of the File Select dialog box contains an input box for entering file names from the keyboard. "*.VOC" should be high-lighted within this input box. Just below the input box is displayed the current path. A large list box is displayed in the center and to the left of the File Select dialog box. All of the files with a VOC extension in the current path are displayed. This list box is used to quickly and easily select sound files without having to type them in. To the right of the list box is another list box that displays the disk drives on your system. This list box is very handy for selecting other drives and subdirectories. Both disk drives and subdirectories are displayed in this list box. Selecting the ".." selection will cause the current path to fall back one directory level. In other words, if the path displays: C:\BLASTER\ Choosing the ".." will change the path display to the root directory or: C:\ At the bottom of the File Select Dialog box is a row of six light blue buttons. The functions of the buttons are described below: PLAY Play the selected sound file. You can choose this function from the keyboard by using ALT-P. RECORD Record a new sound file. Choosing this function brings up the Record dialog box. We'll learn more about it later. You can choose this option from the keyboard by using ALT-R. DELETE Delect the selected sound file. Because sound files take up quite a bit of disk space and experimentation is usually required to get the effect you want, I have included an option to "clean up" un-needed sound files. Please be very careful when using this option! You can choose this option from the keyboard by using ALT-D IMPORT Import other sound file formats. Choosing this function brings up the Import dialog box. Windows 3.1 Wave files, raw SND files and Amiga IFF files can be loaded into BLASTER Master from here. We'll learn more about importing files later. You can choose this function from the keyboard by using ALT-I. ACCEPT Accept the selected sound file for editing. Mouse users can also "double click" the left mouse button to select a file for editing without using this button. Keyboard users can choose this option by using ALT-A. QUIT Quit BLASTER Master and return to DOS. You can choose this option from the keyboard by using ALT-Q and [ENTER]. Sound Blaster Pro users will also see four controls for adjusting the onboard mixer. The Master volume, VOC player volume, Microphone and Line In volumes can all be quickly adjusted by using these sliders. These controls are active during playback. PLAYING A SOUND FILE Now let's select a file and play it back. The file list box should display the file EXAMPLE1.VOC. Using your mouse, place the white arrow over EXAMPLE1.VOC and press the left mouse button only once. If you are using the keyboard, press the TAB key once to highlight EXAMPLE1.VOC and press [ENTER]. The file name input box should now display "EXAMPLE1.VOC" instead of "*.VOC". Using the mouse once again, place the white arrow over the PLAY button and click the left mouse button once. Keyboard users can press the ALT key and the P key at the same time. A red, shadowed box will appear with some useful information about the sound file during playback. This is the Playback Information box. It tells you the name of the file, how big it is, what the sample rate is and the type of file. Playback can be stopped by clicking the left mouse button or pressing the [ESC] key. Sound Blaster Pro users can also adjust the various mixer volumes during playback. ENTERING THE WAVE EDITOR Now that we've heard the file, let's take a look at it! Using your mouse, place the white arrow over the ACCEPT button and press the left button once. Keyboard users can press [ENTER] or use ALT-A. The File Select dialog box and the logo will disappear. A graphical representation of the sound file will be drawn on the upper section of the screen. From this display, we can see where segments of our sound files start and end. The width of the screen represents the playback length of the file. The height of the screen represents the amplitude or volume of the playback. This visual interface makes it very easy to see individual segments of sound files. The vertical grid lines divide the sound file into seconds or in the case of very long files, into minutes. With very little practice and experimentation, you will quickly begin to develop a "feel" for editing sound files. Below the wave form display is some very useful information about the file we are currently editing. The name of the file, length sample rate and playback time is always displayed. To the right of this information are eight buttons. These buttons are used to select DSP functions that will act upon the entire file. Placing your mouse cursor over a button and pressing the LEFT mouse button will select the function. Keyboard users can use the TAB and Shift-TAB keys to highlight the desired option and then pressing the ENTER key to select that function. The two farthest buttons to the right are very important. They are the NEW and MORE buttons. Selecting NEW will allow you to select another sound file. Don't press it yet though! The MORE button will cause the function buttons to change. Select the MORE button now. You should see seven more functions appear. The MORE button is still there to go back to the original functions. Current Time Display Lets move the mouse cursor across the wave form graph. You will notice that the time display across from the Playing Time changes as we move the mouse cursor back and forth across the wave for graph. This feature displays the approximate time of the sound file at the point the mouse cursor is positioned over. I am sorry but keyboard users do not have an equivalent for this in the software. Setting the Marker With the mouse cursor still in the wave form graphic area, press the RIGHT mouse button. Just below the mouse cursor position on the blue bar a small white triangle will appear. This marker will come in very handy in the future. It can be used to mark a reference point as a reminder. The INSERT and MIXER functions can also use the marker as the position to begin their processes. The Vanishing Menu When we move the mouse cursor to the upper most area of the wave form graphic area, a pull-down type menu will appear. It will remain visible as long as the mouse cursor is over it or the SHIFT key is held. Moving the cursor away will cause the menu to vanish once again. Now you see it... now you don't! The Vanishing Menu contains four sub-menu options: FILE These menu options allow you to select a NEW file, SAVE the current file, SAVE AS a new name or sound file format, IMPORT a new sound file, RECORD a new sound file and QUIT the program and return to DOS. The ABOUT option will display some very useful information like the BLASTER Master version number, your soundcards DSP version and the DMA, IRQ and PORT settings. OPTIONS These menu options allow you to LOOP play the sound file over and over again, SAVE SCREEN COLORS and if you have made a change to the sound file, an UNDO or RETURN TO ORIGINAL option is available. TOOLS These menu options correspond to the same DSP functions as the lower buttons. There are some options not available from the buttons: The PANNING function allows a stereo file to pan from speaker to speaker. The SILENCE function allows silence bytes to be inserted into the file to extend the playback time. The MAKE MONO function converts a stereo file to a mono file. The HISS function (Noise Gate) removes all bytes below a certain amplitude. HELP This menu option displays a simple online help screen. The DSP functions are described in more detail than just the button labels. This is a handy reminder from time to time if there are features that you have not used very often. Marking a Block Now that we have had a look at functions for working with a whole sound file, we are ready to see some Block functions. Processes that function with segments of the file, like cutting, saving and moving segments require that way to identify the area we want to work with. This selection process requires a mouse. Keyboard will not be able to select a block for processing. We mark a block by placing the mouse cursor over the wave form graph at the point we want to start and pressing the LEFT mouse button. A blue line will appear at the point the mouse cursor was over and the function buttons will disappear. If you have selected an area you do not want, press the ESC key and the blue line will disappear and the function buttons will pop up again. The blue lines can not be moved with the mouse. Assuming the first point is what we want, position the mouse cursor over the wave form graph where you would like the block to end and press the LEFT mouse button once again. Our block should be surrounded by a blue box and eight new buttons will appear where the function buttons were before. Since we can not move the blue box lines, it is always a very good idea to select slightly more area than we need. You can ZOOM into the block and continue to mark new segments until you have exactly the block you need. Don't worry if you don't like the new block, UNZOOM will return you to the previous segment. You can ZOOM up to 128 times or until the sample to pixel resolution is 1:1. The current resolution is displayed over the function buttons to the right of the screen. The size of the current block is displayed to the left of the File Size display. The playing time of the block is similarly displayed across from the Playing Time. With very little practice, you will quickly learn to mark a block with surgical precision. Block Functions As mentioned earlier, the DSP function buttons have been replaced with processes that act upon the selected block rather than the whole sound file. Even the Vanishing Menu has different options and a different help screen now. The PLAY button now will only play the block and the NEW function discards the blue box and returns to the original file. The CUT Function The most common editing feature used in block mode is the CUT. There is usually some unwanted sample data at the beginning and end of the sound file that needs to be removed. There may also be some undesirable vocal components like "ughs" and breath sounds that should be removed to have a more professional sound. We will cover all the functons later in the tutorial. Handy Tip When trimming the front and end of a new sound file, always CUT the left-most segment first. BLASTER Master uses a DOS function to resize an UNTITLED or edited sound file when the right-most segment is removed. This is much faster than having to make a copy of the new file. You'll like it! The ZOOM/UNZOOM Functions The currently selected block can be displayed in more detail by using the ZOOM function. Position the mouse cursor over the ZOOM button and press the LEFT mouse button. The wave form graph will change to display the block only. A new block can be selected with the mouse cursor and LEFT mouse button as before. We can continue to mark and ZOOM until we reach a sample to pixel resolution of 1:1. Selecting the UNZOOM function will redisplay the previously marked block in ZOOM mode until we return to the original block. Try the UNZOOM function now. Exiting the Wave Editor Now that we have seen how to mark a block, select the NEW button and press the LEFT mouse button (or press the ESC key). The blue box will disappear and the DSP function buttons will reappear. Select the NEW button again (or press the ESC key) and you will be returned to the File Selection Dialog Box. If a change was made to the sound file, a dialog box will appear to SAVE the changes. We will talk more about that in the next section of this tutorial. Handy Tip You can quickly quit BLASTER Master and return to DOS from the Wave Editor by pressing CTRL-Q! Using the DSP Functions Now that we have taken a quick tour through BLASTER Master, you should be familiar with the user interface and navigating through the software. We will cover a few of the more common DSP functions that operate on the entire sound file. Some of the functions will require some parameters and other functions will not. The functions requiring user supplied parameters will require some experimentation and experience to achieve the results you want. The ECHO Function An echo occurs when accoustic sound waves that have passed our ears are reflected back from some surface that is off in the distance. The distance of the reflecting surface and how well the sound is reflected determines the kind of echo that is produced. One of the more common DSP functions and also one of the more versatile functions is the ECHO. Everything from short, gated reverbs to continuous canyon echos can be processed using this single function. A bit of echo can help to sweeten a voice recording and produce a more professional sound. Three user supplied parameters are required to process an echo: Time Delay The time delay determines the point in which the echo is returned. The range of this parameter helps determine whether a reverb type effect is achieved or a long canyon type echo. This parameter ranges from 60 milliseconds to 400 milliseconds. The majority of the echos desired will probably be in the 60 to 200 millisecond range. This parameter is the same element as the distance of the reflective surface in an accoustic echo. Mixture The mixture is how loud the echos will be mixed into the original sound. This is a very important parameter for how the resulting echo will sound. Remember to not go overboard on this setting. A setting of 30% to 60% is usually all that is needed to achieve a very realistic result. This parameter is the same element as how well the distant surface reflects the accoustic sound waves. The louder the accoustic echo is returned, the more reflective the distant surface is. Finite or Infinite Filtering This parameter determines how many times the echo will be repeated. Finite means the echo will only be repeated once. This is very good for gated reverbs or when the sound file is very complex. The Infinite filter causes the echo to repeat over and over until it eventually fades away. This is a more natural echo but does not lend as well to reverb effects of short delay. Echoing a Sound File We will apply some echo to the SAMPLE1.VOC sound file now. From the File Select dialog box, select the SAMPLE1.VOC file. As discussed earlier in the tutorial, you may select this file by using the mouse or the keyboard. If you have correctly selected the sound file, you should now be in the Wave Editor and SAMPLE1.VOC should be graphically displayed. Using the mouse, place the cursor over the ECHO button and press the LEFT mouse button. Keyboard users can press ALT-E to select the ECHO function. A ECHO function dialog box will appear in the center of the wave form graph. We will need to add the delay and volume mixture parameters using the keyboard. The Delay field should be highlighted. We will use a delay of 150 milliseconds. Enter the following number: 150 [ENTER] The Mixture field should now be highlighted. We will set the volume mixture to 45. This will give an echo that is not too overwhelming. Enter the following number: 45 [ENTER] The OK button should be highlighted now. There is another parameter that we could choose to select at this time. That parameter is the FINITE or INFINITE filter. The ECHO function defaults to the INFINITE option. If you wish, you can use your mouse to toggle between the FINITE and INFINITE parameter to get a feel for it. For the purposes of this experiment, select the INFINITE option if it is not already selected. Using the mouse, select the OK button. A graphical guage will pop up in the wave form graph in the lower left corner. This guage is used with most functions to let us know how the function is progressing. A percentage completed will also be displayed to the right of the guage. Depending on the speed of your PC, this function will take a few seconds. When the function is completed, the wave form graph will be redisplayed and SAMPLE1.VOC will be replaced with UNTITLED. This tells us that the current file has been modified. BLASTER Master never changes the original file unless you choose to save on top of it. It is a very good idea to always rename the file unless disk space is getting low. Working with digital files gobbles up hard disk space very quickly! BLASTER Master will warn you when your disk space is marginal. Select the PLAY function and we will hear what our sound file sounds like with echo. You can select the PLAY function by using the mouse or keyboard users can press ALT-P. You should hear a very noticable echo in the sound file. By using different delay, mixture and filter combinations you can achieve a wide variety of effects. I will leave it to you to experiment with these settings. Saving the New Sound File Now that we have applied some echo to our sound file, we need to save it and try some other functions. We could continue to add more DSP functions to the sound file. There is no limit to how many functions can be applied to a single sound file. Later in the tutorial we will discuss combining functions to achieve some interesting effects. Using the mouse, place the cursor over the NEW function and press the LEFT mouse button. The Save File dialog box will appear in the center of the wave form graph. The cursor will be in the file name field of the dialog box. Using the keyboard, enter: ECHO1 We could save our file in another format besides VOC. In the lower right of the Save File dialog is a series of radio buttons to select the desired format, such a WAV. This dialog always defaults to the VOC file format. Just below the file name and to the left are three option buttons. These options can be used to SAVE the file as named, RETURN TO THE EDITOR and make more changes or DON'T SAVE and discard the sound file and lose the changes. For purposes of our experiment, we want to SAVE the sound file. When you begin experimenting on your own, you will often choose to not save the sound file to conserve disk space. BLASTER Master will return you to the File Select dialog box. You should see ECHO1.VOC included with the other sound files. The REVERSE Function Because digital files are nothing more than a series of amplitude values captured at a constant rate, the playback can be easily reversed by simply reversing the order of the samples. In other words, the last sample byte becomes the first sample byte and the first sample byte becomes the last sample byte. All the subsequent sample bytes are reversed in this same manner until the whole file has been processed. This is one of the easiest of the DSP functions to do. It is also one of the fastest. No user supplied parameters are required because of the simplicity of the process. Because of the simplicity of this function, we will not go over the steps for accessing it. We will combine the REVERSE function with ECHO for a very interesting effect a bit later in this tutorial. Fun with the REVERSE Function There is not that much practical use for the REVERSE function, but you can have alot of fun with it. Television evangelists can spend hours and hours looking for those pesky satanic references in rock and roll lyrics. Many phrases will make new phrases when reversed and auditioned with a bit of imagination. The reversed words tend to be one or two syllable words but they are there none the less. I have always poked fun at this but maybe there is something to it afterall... If you reverse Robert Johnson's 1935 song, "Hellhound on My Trail" it seems to very clearly state, "He's someone that I like!". Blues legend maintains that Robert Johnson sold his soul to the devil to be the world's greatest blues singer. Maybe they are right. Those of us who can remember that Paul McCartney had a band before Wings may remember that "Number Nine" from The Beatles White Album song "Revolution Number Nine" played in reverse sounds like "turn me on, deadman". It does indeed. The British accent helps though. When I reverse my own Texas drawl saying "Number Nine" it sounds more like "turn me own, dumb dumb". Did you know that Johnny Weissmuller's famous Tarzan yell sounds the same after being reversed? It does. Try it. Who ever created the original effect spliced the tape onto itself in reverse to extend the call. Using the ZOOM feature will reveal the actual point the sounds connect. The warbled yodel in the Tarzan yell is produced by playing the original vocal at a faster speed and mixing it back in several times. That explains why neither Johnny or Carol Burnet could ever reproduce it exactly. Someone put alot of work into it with tape and scissors! Another interesting experiment with the REVERSE function is to record your voice saying your name and then reverse it. Practice saying your name in reverse until you can record it and reverse it to produce your name forward again. Whereas this ability may not help your resume' very much, it is fun for children of all ages. Combining the REVERSE and ECHO Functions This experiment will combine the REVERSE and ECHO functions to produce a very different type of echo than is found in the real world. This is only one example of how functions can be combined to produce some very interesting effects. You will soon be able to use your imagination to achieve your own special effects. I also recommend you begin to pay attension to the special effects in movies and on television. You will begin to recognize how the sound F/X experts make their magic. Select and REVERSE the Sound File Using the same steps to select a sound file as we did earlier in this tutorial, select the SAMPLE1.VOC file and enter the wave editor. First we will REVERSE the file. Select the REVERSE button using the mouse cursor and the LEFT button. A small dialog box will appear in the center of the wave form graph with only two options, OK and CANCEL. Choose the OK button and the sound file will be quickly reversed. Once again the file name has changed to UNTITLED. Select the PLAY option to audition the reversed sound file. Did it sound like you expected? ECHO the Reversed Sound File We will now select the ECHO function exactly as we did before, only this time the file is in reverse. Follow the same steps and parameters as before. For added effect, you can use a delay of 200 milliseconds if you wish. Once the ECHO function is completed, the echoed sound file will be redisplayed in the wave form graph. Select the PLAY option again to hear the multi- processed sound file. Reverse the Sound File Again! Once more, select the REVERSE option and process the sound file for a third time. When the sound file is redisplayed, select the PLAY option to hear the results of combining these two functions. Instead of a natural echo, we have the effect of a "reverse echo". The sounds fade into the original instead of fading out. This can be very useful for outer space effects and bizarre Doppler effects. Saving the Multi-processed Sound File Using the mouse, place the cursor over the NEW function and press the LEFT mouse button. The Save File dialog box will appear in the center of the wave form graph. The cursor will be in the file name field of the dialog box. Using the keyboard, enter: ECHO2 As mentioned earlier, we could save our file in another format besides VOC. In the lower right of the Save File dialog is a series of radio buttons to select the desired format, such a WAV. This dialog always defaults to the VOC file format. Just below the file name and to the left are three option buttons. These options can be used to SAVE the file as named, RETURN TO THE EDITOR and make more changes or DON'T SAVE and discard the sound file and lose the changes. For purposes of our experiment, we want to SAVE the sound file. When you begin experimenting on your own, you will often choose to not save the sound file to conserve disk space. BLASTER Master will return you to the File Select dialog box. You should see ECHO2.VOC included with the other sound files. You can use the PLAY option from the File Select dialog box to compare the ECHO1.VOC and ECHO2.VOC if you wish. Using the PITCH Function One of the components of a digital sound file is the Sample Rate. The sample rate is a steady, constant value that reflects how many samples are played during a single second. A sample rate of 22khz (twenty-two kilohertz) means that 22,000 samples are played each second. When the original digital sound file was sampled (recorded), a measurement of the voltage passing through the microphone was made 22,000 times a second. Playing back the file at the same sample rate will reproduce the digital sound file at the exact same pitch it was originally sampled. If we increase or decrease the original sample rate during playback the pitch will change accordingly. The PITCH function is accessed like the other DSP functions in BLASTER Master. It is not one of the default functions that appear when a sound file is first displayed so it is necessary to use the MORE button. It is also included in the TOOLS under the Vanishing Menu, as are all the other functions. The PITCH dialog box uses a rangebar or slider to choose the amount of pitch change. The first time the pitch is changed the sound file will be redisplayed and the file name will change to UNTITLED. All pitch changes to the UNTITLED sound file will be much faster. Only the header will be changed to reflect the new sample rate. Do not confuse the PITCH and the RATE functions. They are very different. We will discuss the RATE function below. Handy Tip When the PITCH function is used the playback speed is also altered along with the pitch. When lowering the pitch you may wish to combine it with the FAST function to increase the playback speed without changing pitch. This is particularly useful with speech type sound files. The vocal inflection will sound more natural. The same applies to increasing the pitch. Use the SLOW function to make the sound file less chattery. Try applying the REVERSE/ECHO/REVERSE technique along with a pitch reduction and playback speed increase. This produces an erie, alien type voice that can be useful for games that you write. Using the RATE Function Unlike the PITCH function that merely changes the rate which a sound file is played back, the RATE function actually changes the sample rate while maintaining the original pitch. The RATE function uses a mathematical function known as spline interpolation. Interpolation can calculate missing samples in the case of raising the sample rate or determine which samples to remove or replace in the case of lowering the sample rate. This function can be very useful for reducing the size of a sound file without using compression (packing). Many sound files will sound no different when resampled to a lower rate. Aliasing If after using the RATE function to lower the sample rate. the sound file begins to get a tinny sound, then try again at a slightly higher sample rate. The tinny sound is called aliasing. It is produced when the sample rate is not high enough to capture the higher frequencies accurately. The Nyquest theorum states that a sound file must be sampled at twice the sample rate of the highest frequency. In other words, to capture frequencies up to 11khz requires a sample rate of at least 22khz. Many people falsely believe that a high sample rate will insure a clear sample with very little hiss or background noise. The sample rate is used purely to capture frequency range. The signal to noise ratio is determined by the number of bits used in each sample. A 16bit file has a theoretic signal to noise ratio of 96db. An 8bit file can only have a signal to noise ratio of 48db. Using the VOLUME Function Some digital sound files may not be sampled at a audio volume that suits your purposes. The VOLUME function is used to adjust the amplitude of digital sound files. Increasing the audio volume of a sound file will not introduce any new noise to the signal but it will increase the volume of any noise present. This is almost never a problem unless the original sound file is of a very poor quality. The VOLUME function is one of the easier DSP functions to do. It multiplies each sample byte evenly by a factor that will increase or decrease the amplitude. It is very usefull when combined with the MIXER functions. The VOLUME function is accessed like all the other DSP functions. It is also available as a block tool and is often more desirable for reducing noise than is the MUTE block tool. Two user supplied parameters are required to perform this function. First, we must tell the the function whether we will be increasing or decreasing the volume. Enter either an "I" to increase or a "D" to decrease. Do not use the quotation marks! Next we must supply the function with the factor in which to adjust the volume. In the case of decreasing the volume, the factor must be between 99 and 1. This will lower the amplitude to that level relative to the original sound file. A sound file can be increased over a much wider range. The volume can be doubled by entering a value of 100. This process can be ran several times if some tweaking is required. The VOLUME function will recreate the sound file as UNTITLED and redisplay the processed file like the other functions. Go through the same steps to save the file as before. Using the FADE Function The FADE function is very similar to the VOLUME function. Instead of applying a constant factor that the samples will be scaled to, it uses an increasing or decreasing factor to cause the sound file volume to fade in or to fade out. A FADE IN assumes you will be starting at the beginning of the sound file. You can FADE IN from the beginning to approximately half way into the file. The FADE OUT function assumes that you will be fading out to the end of the sound file. You can begin the FADE OUT function approximately half way into the sound file to the end. This is an extremely usefull DSP function and can be applyed to almost any digital sound file. Determining the Fade time Usually the amount of time to fade can be determined visually by using the time grid that is displayed in the wave form graph. A more specific method is to use the mouse cursor to determine the FADE IN time by moving it over the wave form graph and noticing the current time as it is displayed to the right of the total playing time. Another method that can be applied to both the FADE IN and FADE OUT time window is to use the mouse cursor combined with the LEFT mouse button to mark a block at the beginning or ending of the sound file. The playback time for the block is displayed to the right of the total playback time. After noting the block time, use the NEW button to exit block mode and return to function mode. Be carefull to only press the NEW button once. Otherwise you will be returned to the Select Soundfile Dialog box. If you are working with an UNTITLED sound file and you accidentally press the NEW button twice, the Save Soundfile Dialog box has a Return to Edit button that will put you back in function mode. Cross-fading The FADE function can also be used very effectively with the MIXER function to apply cross-fading of two files. Cross-fading occurs when one sound file fades out as another sound file fades in. Cross-fading is very commonly used in broadcast radio to segue one song into another. Disk Jockeys use a mixer board rather than digital signal processing. An example of cross- fading using BLASTER Master would be to fade out about 4 seconds of the first sound file and fade in 4 seconds of the second sound file. Using the MIXER function, mix the second sound file into the last 4 seconds of the first sound file. Don't worry if you don't know how to use the MIXER function. That is our next topic. Using the MIXER Function The MIXER function is a very powerful tool in our arsenal of DSP functions. It literally combines two digital sound files into a third combined sound file. The combined sound file can then have another sound file mixed in, and so forth. Each generation will lose some clarity so there is a limit to how many sound files can be mixed in and still achieve decent fidelity. You can also choose the exact point to mix a sound file in using the mouse cursor, the marker, a certain time into the sound file or a certain number of samples into the the sound file. One primary thing you should be aware of is the mixer does not attempt to adjust the sample rate of the sound file being mixed in if it does not match the sound file selected for editing. This can work to your advantage for achieving certain effects. In most cases you will want to process one file or the other using the RATE function if the two sound files have different sample rates. The amplitude or volume can be adjusted for the sound file being mixed in. The basic use of the MIXER function is quite simple but getting the sound balance adjusted correctly and selecting the point to begin the mix will take some practice and often several attempts to get it just right. Selecting the Mix File We begin our MIXER experiment by selecting the original sound file to be processed. Use the same steps as before to select a sound file and display it in the Wave Form Graphic Display. When the MIXER function is selected using either the Function buttons or from the Tools menu of the Vanishing Menu, the familiar File Select Dialog box will be displayed across the Wave Form Graphic Display. The heading of the dialog box will be SELECT SOUND FILE TO MIX IN. This can be disorienting the first time the MIXER or INSERT functions are selected. Both functions use the File Select Dialog box to choose the secondary sound file, so don't be confused. You are still in Function mode. Select the Mix in sound file using your mouse or the keyboard just like you would select any other sound file for editing. (You could also RECORD a new sound file to Mix in. We will not go into that at present.) Remember! The MIXER function does not adjust the sample rate of the sound file being mixed in. If you select a sound file with a lower sample rate, the mixed in sound file will playback at a faster rate. If a sound file with a higher sample rate than the original is chosen, the mixed in sound file will playback at a slower rate. If the sample rates do not match, you can always first process one of the sound files using the RATE function as described earlier in this tutorial. After selecting the Mix in sound file, the Mix In Volume dialog box will be displayed. Choosing the Mix In File Volume The Mix in sound file can be added at a different volume than the original sound file. The Mix in Volume has a range of 1 to 200. To use the original volume of the sound files, enter 100 as the volume. To lower the volume, enter a value less than 100. To boost the volume, use a value that is greater than 100. If you are adding background sounds to the original sound file, you will probably want to use a lower volume than 100. If you are mixing in a sound file over a bed or background sound file, then you may wish to boost the Mix in sound file. In either case, you may wish to experiment and apply the mixing more than once. Remember to use a different name each time you save the processed sound file. You will have to enter the Mix in Volume value using the keyboard. Choosing the Mix In Point After entering the Mix in Volume, a dialog box will be displayed for you to select how you want to select the point to begin mixing. The Mix in Point can be selected using your MOUSE cursor, the MARKER, TIME into the original sound file or SAMPLES into the original sound file. Using the MOUSE Option Choosing the MOUSE option will cause the Function buttons to disappear and a graphical box will appear where the buttons were before. Move the mouse cursor over the Wave Form Graphic to the point you wish to begin the mix in and press the LEFT mouse button. If you wish to mix in from the beginning of the original sound file, move the mouse cursor as far to the left as it will go before you press the LEFT mouse button. Using the MARKER Option Choosing the MARKER option will begin the mix in from the point that the marker is set. If the MARKER is not set, the process will abort. Using the MARKER is a very handy method for preselecting the mix in point. Remember, the MARKER can be set by pressing the RIGHT mouse button with the mouse cursor over the Wave Form Graph. The MARKER appears as a white triangle just below the Wave Form Graph. Using the TIME Option The TIME option is a very accurate method of selecting the mix in point. It offers selectability up to 1/1000th of a second. The time value is entered using the keyboard. Using the SAMPLES Option The SAMPLES option allows you to select the mix in point at a sample level. It is also a very accurate method of selecting the mix in point. Both the TIME and SAMPLES options will be used in special cases. The MARKER and MOUSE options will usually be more than adequate for general use. Creating Special Effects with the MIXER Function The MIXER function can be used to create many special effects. Longer echo delays can be processed using the MIXER function. You can not mix a sound file onto itself, but the SAVE AS... option can be quickly selected from the Vanishing Menu's FILE menu to make a copy of the original sound file. Some interesting speech effects can be created by using several DSP functions to generate a very altered speech file. Then overlay the original, unprocessed speech file to add clarity back in. Like all the DSP functions in BLASTER Master, you are only limited by your imagination. Using the INSERT Function The INSERT function uses the same basic user interface as the MIXER function. There is no VOLUME parameter required. Unlike the MIXER function, INSERT will adjust the sample rate or the insert sound file to match the original sound file. It will also adjust the number of channels of the insert file to match the original sound file. In other words, a mono sound file inserted into a stereo sound file will be coverted to a two channel sound file. A slight delay is added to the converted channels to simulate stereo and add more depth. If a stereo sound file is inserted into a mono sound file, the two channels of the stereo sound file will be compared and mixed where needed. The INSERT is a very fundimental DSP function. You will find yourself using it quite a bit. Using the SLOW Function The SLOW function is a tool for very specialized use. Essentially, it slows the playback speed of a digital sound file without effecting the pitch. The playback speed will be approximately half of the original, depending on the sound file used. It requires no input parameters. The function itself is a fairly involved process. It scans through the file and duplicates very small segments of the waveform to extend the time. It uses some inteligence to find the segments and then cross-fades the splice points. It works best with simple speech tracks but can also be used effectively with more complex sound files like music. Musicians will find it particularly useful for slowing down solos for closer study. Hardware devices to perform the same function, such as the SloMo, cost several hundred dollars and are limited to a few seconds. The SLOW function can also be very useful when used with the PITCH function. When increasing the PITCH, use the SLOW function to give the speech a more natural and less chattery sound. Using the FAST Function We could not have a SLOW function without a FAST function as well. The FAST function is a simpler process and does allow for user selectable effect. Choosing the FAST function displays a dialog box with a rangebar or slider for selecting how much to speed the playback. Like the SLOW function, it works best with simple speech type sound files but music can also be processed effectively. The function works by removing minute segments of the waveform and cross-fading the splice point. The FAST function also works well when used in conjunction with the PITCH function. When using PITCH to lower the sound file pitch, apply the FAST function to give the resulting sound file a more natural sound. Both the FAST and SLOW functions are interesting effects and worth some time experimenting with. Using the VOCALS Function The VOCALS function requires a stereo sound file. It can be used to eliminate the vocals from music type sound files. The results will vary from sound file to sound file. The process works by inverting one channel of a stereo sound file and mixing it into the remaining channel to produce a mono file. All of the waveforms that are in the center of the stereo space are canceled out. Vocals are usually mixed in the center so they are usually canceled out. Unfortunately the solos are also usually mixed in the center so they are also canceled out. As mentioned above, the results are determined on how the original stereo recording was mixed and balanced. You can sometimes improve the results sometimes by tweaking the balance of the source channels during recording. The VOCALS function does work just as well as the $350 devices that are sold in magazines. There are no user supplied parameters required for this function. It is alot of fun and worth experimenting with. Using the PANNING Function The PANNING function also requires a stereo sound file. PANNING causes the volume to pan from one stereo channel to another. The user may select a left channel to right channel pan or a right channel to left channel pan. It is a very simple process can be very effective and useful. The PANNING function can only be accessed from the TOOLS menu of the Vanishing Menu. Using the SILENCE Function The SILENCE function will insert silence bytes into a stereo or mono sound file. It is very usefull for extending the playback time for syncing with a graphic file, such as an FLI file. It can also be indespensible when mixing multiple files together. Using the MAKE MONO Function The MAKE MONO function requires a stereo sound file. It will convert the stereo file to a mono sound file. This is very handy for reducing the size of a file by half or for users with a mono only soundcard. Using the HISS Function The HISS function can be more accurately described as a noise gate filter. There is a very popular utility with a similar name. I had several requests from my registered users to add this function, so I retained the name. It essentially replaces sound bytes below a certain amplitude with silence bytes. It is very usefull with spoken word sound files to remove any background noise. Using the PACK/UNPACK Functions The PACK/UNPACK functions only work on mono sound files. Packing involves applying a real-time compression known as ADPCM (Adaptive Delta Pulse Code Modulation). It is not a lossless compression and should only be used when absolutely necessary. Depending on the amount of compression applied, the loss in clarity will be quite apparent. An example of 2:1 compression is as follows: The first sample byte is preserved uncompressed as the "reference sample". The difference between that sample value and the next sample value is stored as a 4 bit value in the next byte. Each subsequent sample is then stored as the difference between the last value as a 4 bit value. Each byte after the first sample byte then contains the value of two sample bytes. Because waveforms follow a rising and falling pattern, an adaptive difference is applied to help minimize the amount of clarity loss. This adaptation is different for one ADPCM algorythmn to another. The UNPACK function will only work with a previously packed sound file. It retunrs the sound file to an uncompressed format although it can not restore the lost resolution of the original sound file. It is necessary to UNPACK a packed sound file before most of the DSP functions can be used. Compression works best with speech type sound files. Music type sound files will usually have the pitch and frequencies altered too much for any practical applications. Once again, do not use compression unless absolutely necessary. Using the SCOPE Function The SCOPE function is not actually a DSP function at all. It is very entertaining and educational and was included for those purposes. It can be very useful for adjusting the input volume of your input source. That is the reason it is included in the RECORD dialog functions. The SCOPE function can be exited by pressing any key or clicking either mouse button. Just connect a microphone, select the SCOPE function and speak into it. Sound Blaster Pro users will have the option of selecting the input source (Microphone, Line In or CD Audio). The input source can be selected from the RECORD function. You will get to see your voice as well as hear it. Children particularly love the SCOPE function. The SCOPE function uses the direct mode of sampling from the ADC (Analog to Digital Converter). The sample rate is set at the highest number of cycles your processor can perform. The smoothness of the waveforms are achieved using two page animation mode. Using the BLOCK MODE Functions We have seen how processes can be performed on an entire digital sound file. We have also combined several functions to create new and exciting special effects. Now it is time to explore some of the specific editing functions and block tools. There will usually be sections of the sound file at the beginning and end that need to be removed. There could also be noise or unwanted vocal pauses like "ughs" that can be cut from the sound file. A sound file may contain a segment that needs to be moved or copied to another portion of the file. We will go over each editing function in detail in this section of the tutorial. Entering BLOCK MODE BLOCK MODE can only be entered by using a mouse. There is no keyboard equivalent to select a section of a sound file. To select a section of a file, move the mouse cursor over the waveform graph and press the left mouse button once. A blue vertical line will appear at the point where the mouse cursor was. The DSP Function buttons will disappear and you will be prompted to select the next section of the block. You can select from either side of the first mark. Press the left mouse button once again to select the next section of the block. The block selected will be enclosed within a blue box. The Edit Mode Function buttons will appear where the DSP Function buttons were before. The size in bytes of the block will be displayed next to the file size. The playing time of the block will be displayed next to the playing time of the full file. Important Tip! Always select more of the file for your first (primary) block than you want. Once a block is marked you can not use the mouse to move the blue lines, although you can select another block within the original block after selecting the ZOOM function. The ZOOM function will allow you to very accurately select exactly the section of the file you wish to modify. You can always use the UNZOOM function to return back to your previous block if you want to try again. With a very little bit of practice, you will soon be able to select exactly the block you need. The BLOCK MODE Vanishing Menu The Vanishing Menu options are different in BLOCK MODE. It is accessed the same way but the sub-menu options have changed: BLOCK These menu options allow you to select a NEW block, CUT the block from the sound file, SAVE the block as a new sound file, MOVE the block to a new location in the sound file, make a COPY of the block in a new location in the sound file or to PLAY the block. OPTIONS These menu options allow you to LOOP play the block or sound file over and over again and choose whether the PLAY function will only play the selected block or the entire file. TOOLS These menu options correspond to the same DSP functions as the TOOLS button that appears on the lower screen. We will discuss them in detail later. HELP This menu option displays a simple online help screen. The BLOCK MODE functions are described in more detail than just the button labels. This is a handy reminder from time to time if there are features that you have not used very often. The BLOCK MODE Functions The PLAY Function The PLAY function in BLOCK MODE usually plays the selected block only. This is very useful for verifying that you have exactly marked the section you want. You can play the entire file by choosing the Options sub-menu from the Vanishing Menu and set playback to ALL. The TOOLS Function This function displays a menu of DSP function tools that will modify the selected block. Some of the tools are much the same as the DSP functions for modifying the complete file but others are more specific to a block of sound. These unique functions can always be applyed to the entire file by selecting a block large enough to contain the sound file. The BLOCK MODE tools are: LOOP This function will repeat the block in the soundfile upto 10 times. This function is very handy for making a sound stutter or to create a pad for later mixing into another file. The number of loops can be selected using a sliding range bar with options from 2 to 10. This function will increase the size of the file accordingly. MUTE This function will replace the selected block with silence. This can be very useful for removing extraneous sounds without changing the playback time of the sound file. REVERSE This function will reverse the playback of the block. PITCH This function will raise or lower the pitch of the selected block. The amount of pitch adjustment is based on a percentage of the original sample rate. The adjustment is selected by using a sliding range bar. ECHO This function will echo the selected block. The input parameters are the same as the DSP Echo function for processing the whole soundfile. VOLUME This function will increase or decrease the playback volume of the selected block. The input parameters are the same as the DSP Volume function for processing the whole soundfile. This function is often more desirable for removing background noise than the MUTE function. Whereas the MUTE function is dead silence, the VOLUME function can be used to reduce the background sound and retain a certain amount of ambience. ACCELERATE This function will gradually increase the pitch and playback speed of the selected block. DECELERATE This function will gradually decrease the pitch and playback speed of the selected block. The CUT Function This function will remove the selected block from the sound file. It is very useful for removing unwanted sections at the beginning and ending of a sound file. It can also be used to remove vocal "ughs" and such and to shorten the gaps between words and sentences. Handy Tip The CUT funtion will use a DOS trick to shorten the length of a file when you are cutting the far right section of an UNTITLED sound file, i.e., one that has already been edited at least once. The block can not be ZOOMed to use this fast method. If you want to remove sections from both the beginning and end of a sound file, remove the beginning section first! This will create an UNTITLED sound file and make cutting the end of the sound file much faster. The NEW Function This function will allow you to select a new block for modifying. The blue box will disappear and you will be returned to the DSP functions for processing the whole sound file. The ZOOM Function This function will display the selected block across the Waveform screen graph. Once a block has been ZOOMed, you may select another block until the display resolution reaches 1:1. BLASTER Master supports upto 64 ZOOM levels. The UNZOOM Function This function will return the screen to the previous resolution before the last ZOOM. By combining the ZOOM and UNZOOM functions, you can very accurately select exactly the section of the sound file to be modified. The SAVE Function This function will save the selected block as a new sound file. The original sound file is left exactly as it was. You will then be prompted to return to editing the original sound file or to edit the new saved block. The MOVE Function This function will move the selected block to a new location within the sound file. You can have alot of fun altering speech files and such by moving the words around to make new sentences. The COPY Function This function will copy the selected block to a new location within the sound file. The original block is left intact. This is a very handy function for making RAP type sound files. NOTE: This function is only available from the BLOCK sub-menu of the Vanishing Menu. Exiting BLOCK MODE Clicking the NEW button will exit BLOCK MODE and return you to the DSP Functions. You also have the keyboard options of using the ESC key or pressing ALT-N. This is also the method for selecting a NEW primary block for modifying. Summary We have now covered the functions and techniques needed to get the most from BLASTER Master. With a little practice you will develop the skill to manipulate your sound files like an expert. With a little imagination, the possibilities are endless! Because I am constantly adding new features and improving the interface, BLASTER Master will always be the most advanced digital editor available. Please refer to the BMASTER.DOC file for a listing of BBSs and online services where you can find the latest update of BLASTER Master. It is also available on hundreds of other BBSs around the world. I appeciate any help you can offer by uploading BLASTER Master to any BBSs you can! Thank you for using my software. BLASTER Master (c) Copyright 1993 by Gary Maddox, all rights reserved.