DM10 Audio Lab getting ready

Transcription

1 DM10 Audio Lab getting ready Download the zipped AudioLab folder linked from the A7 page. Unzip the folder (right-click and Extract All). Use the files in the unzipped folder for this lab practice. Download Audacity from the website link on A7. Install it on your computer unless you have other audio editing software that you prefer. Audacity is audio editing software that does most of the basics, and it s free.

2 Open the Audacity software on your computer. Go to the Edit>Preferences menu to open a window like shown below. You can probably leave Device settings at the default, but change Channels to 2(Stereo) if needed.

3 Next you ll do some destructive editing. Clipping original waveform Doing this to a sound file is destructive editing. clipped waveform Go to Project>Import Audio, find your unzipped audio lab folder and import thx.wav Look at the waveform, listen to it (spacebar). Now you get to ruin it.

4 Clipping thx.wav original waveform With thx.wav open in Audacity, click anywhere inside the waveform to set the cursor, then select the entire waveform (Ctrl+a). The background color will change when selected. Go to Effect>Amplify and you will get a window like shown here. Change settings to match this screen picture or close. Click OK Look at the waveform change, most of it filling the vertical area. This is clipping, the sound has been distorted and ruined.

5 Pretend you need to save this destructive editing so you can come back tomorrow and ruin it some more.. Go to File>Save Project As clipped thx.wav Hot tip: when saving a file you can create a new folder for the file by clicking this button. Name your folder AudioLab then double click the folder to go inside it so your Audacity files are saved in the new folder. Name your Audacity project thx and be sure the file type is.aup Do not type aup in the file name, let the software add the correct file extension.

6 Now find the folder where you saved the aup. Audacity saved files similar to this on your computer. thx_data folder holds proprietary sound files for this editing to use. thx.aup is a proprietary Audacity project file that has not made any changes to the source thx.wav. This file only describes what to do with the sound, the source sound (thx.wav) has not been changed. aup.bak is a back-up of aup To work on this more tomorrow, I must save the thx_data folder and the thx.aup file. Fundamental concept that must be understood: Media development (audio, video, animation) often has 3 steps and files for each step. 1. source files thx.wav was the source file, larger projects can have many source files 2. project file thx.aup is the editing file with instructions for what to do with thx.wav 3. output file You can export a clipped wav file any time from the aup project file. The exported wav file is the end product ready for use in your slideshow or other production. Save your source files and project files if you want to work on it again.

7 Importing audio files into Audacity Using the same thx.aup file you have open in Audacity, Go to Project>Import Audio, Find the extracted AudioLab folder on your computer. Open the subfolder inside this folder / Music Select a wma file and click Open. The file type is not compatible with Audacity. What happens? Select the midi (mid) file and click Open. What happens? The file type is also not compatible with Audacity without using a converter. Select the Motzart.mp3 file. What happens? The file is compatible with Audacity so you should import this file.

8 Media Development fundamentals When working with Audacity, use File>Open to open aup project files. Remember aup files are instructions for what to do the sounds and not sound files. You should not use the File>Open to open wav or mp3 files. Use Project>Import Audio to open source sound files inside an Audacity project (aup). Whenever you can, use wav files for source audio, mp3 files have typically been compressed with irreversible loss of quality (just like many jpg files). Use File>Export as wav or Export as mp3 to create the output end product. Hope this makes sense. source files project file - output file

9 thx.wav Is this sound mono or stereo? Motzart.mp3 How long in time is this music? After importing an mp3 file you should have two separate sounds showing in Audacity. The thx sound got squished together so the window could hold the much longer Motzart music. You can use zoom tools in Audacity to change your views of the waveforms, just like zooming into pixels.

10 Trimming changing the duration of a sound file Fair Use Guidelines for copyrighted audio is 10% or 30 seconds of the original music, whichever is less. Fair Use is U.S. Copyright provision for using copyrighted media in an educational setting. With your music file open, first determine the length in time. Set your cursor at the end of the song and look at the bottom of the Audacity window. Motzart.mp3 is about 2 minutes, 42 seconds. To calculate seconds multiple 2 min x 60 sec = 120 seconds + 42 = 162 seconds. You can use 10% of 162 which is about 16 seconds. But in this case, the full song has already been edited down from the original 7 minute song so 7x60=420 seconds. 10% of 420 = seconds is less than 42 seconds. You can use 30 seconds maximum according to Fair Use.

11 Trimming Listen to the music, determine what part you want to use. Select this part like words in a document. Watch the lower selection numbers in ( ). This is your selection length in seconds. Grab either end of the selection to adjust. Use the spacebar to play and stop.

12 Use this tool. Use the zoom tools to zoom in and out. Select part of the music like selecting words in a word processor. You can drag either end of the selection to increase or decrease the time. Look at the bottom of Audacity to see exactly how long in time your selection is as you move the selection ends. This selection is a little over 36 seconds. Good, a little more than needed. Selected area is dark gray. Exact timing information

13 New Track Use the copy keystroke (Ctrl+c) to copy the selected area. Then go to Project>New Stereo Track. You may need to use the side scroll bar to see the new stereo track below the others.

14 Use the copy keystroke (Ctrl+c) to copy the selected area. Then go to Project>New Stereo Track. You may need to use the side scroll bar to see the new stereo track below the others.

15 Sample Rate When copying a pasting sound from one file into another, sample rates need to be the same or pasted sounds may sound faster or slower depending on the sample rate differences.

16 Here you see three separate sound files, the bottom is the new Audio Track without anything in it yet. But there is a problem with Sample rate differences. Look at Motzart, it is 44100Hz. Then look at the bottom new stereo track, it is 11025Hz. If we paste Motzart into the new Audio Track the sample rate will be lowered. Instead, you should change the new stereo track Sample rate to 44,100 before pasting the Motzart music into it.

17 Click the little black triangle next to the new Audio Track title. A fly-out menu like shown here will appear, select Set Rate and then Hz. This will change the sample rate for the new stereo track to match the sample rate for the original Motzart music.

18 Here are 36 seconds of Motzart pasted into the new stereo track. Delete the full Motzart music by clicking the X at the left corner of the track. Then delete the ruined thx track the same way so your Audacity project only has the part of Motzart that you pasted. Next go to Project>Import Audio and import the original thx.wav that has not been clipped.

19 Normalize Effect of amplifying the sound to a maximum level without clipping.

20 Here is the Audacity project so far. The Audio Track is the part of Motzart that you selected, copied and pasted. The thx track is the original unclipped sound you imported. What can you tell by looking at these two soundwaves? Which is loudest? Obviously thx is much louder, and will drown out the music when heard at the same time. Try it, put your cursor at the beginning and use your spacebar to hear the mix. To increase the music volume, first select all of it by click-dragging across the waveform. Then go to Effect>Normalize for this window. Click Ok and notice the slight change in the music waveform.

21 Here is the Audacity project so far. The Audio Track is the part of Motzart that you selected, copied and pasted. The thx track is the original unclipped sound you imported. What can you tell by looking at these two soundwaves? Which is loudest? Obviously thx is much louder, and will drown out the music when heard at the same time. Try it, put your cursor at the beginning and use your spacebar to hear the mix. To increase the music volume, first select all of it by click-dragging across the waveform. Then go to Effect>Normalize for this window. Click Ok and notice the slight change in the music waveform.

22 To decrease the thx volume, first select all of it by click-dragging across the waveform. Then go to Effect>Amplify for this window. Change settings similar to shown here and click OK.

23 Mixing Sounds mixing two or more sounds and adjusting their place in time Adding a new sound effect (sfx) to your mix. Go to Project>Import Audio and choose either Gamme.wav or Olacart.wav. A new track is added to your Audacity project. (You may have to use the right scrollbar to see it.) The sfx is probably shorter than the music. Use the Time Shift Tool to move the sfx anywhere you want in time. Listen. Try adding a third sfx play.

24 selection tool music has been moved and now starts about 10 seconds after thx starts With volumes adjusted, next use the Time Shift Tool and move the music waveform so it starts as thx is ending. Or you can use the tool to move thx. Go back to the Selection tool, set your cursor at the beginning of the sounds and Listen. Play with these techniques. These are key techniques for mixing sounds because you want to decide when each sound will play before you mix them together.

25 Fades Select a second or so of sound at the beginning go to Effect > Fade In Select a second or so of sound at the end. Go to Effect > Fade Out How might you use this technique?

26 Pan Stereo sound moving between channels. Go to Project>Import Audio and import the Flyby.wav Look at the waveform. The sound is weak, this needs to be normalized. before Normalize Select the entire flyby waveform and go to Effects>Normalize and click OK in the Normalize window. after Normalize Why can t you pan this sound? You need another channel.

27 Pan Stereo sound moving between channels. You need another channel. Select the entire Flyby waveform and go to o to Edit>Duplicate This will create a copy of Flyby mono, now you have two mono Flyby tracks. One below the other.

28 Pan Stereo sound moving between channels. Now its easy. Use the Envelope tool to fade one track out and the other track fades in. This creates the illusion of sound moving from one speaker to the other. The last step is to convert it to a single stereo track with left and right channels.

29 Pan Stereo sound moving between channels. To convert two mono tracks to stereo track with left and right channel sound differences: Select the little black triangle on the end of the top Flyby track and choose Make Stereo Track Left channel fading out Right channel fading in This will merge the separate tracks into a single stereo track with two channels.

30 Saving the project and the mixed sound Two things to do: save the project and save a mixed wave file. You can save the project with a keystroke or File>Save. Remember which keystroke? To save the mixed sounds as a single wav file go to Project > Export as Wav When you name this new mixed wav file, do not overwrite any of the source files. Why not? Two files: You should have an Audacity project file (.aup) and a wav file of the sounds mixed together. Which file can go into PowerPoint or Impress, the aup or the wav? Which file can you use later to work on this audio editing project?