Editing Digital AudioLab#7

• Audacity is a free, easy-to-use and an open source platform audio editor and recorder for Windows, Mac OS, Linux and other operating systems.

• It is a program that manipulates digital audio waveforms.• It can be downloaded from (http://audacity.sourceforge.net/).

• Audacity can be used to:– Record audio.– Convert tapes and records into digital recordings or CDs.– Edit sound files with many different formats ( MP3, WAV or AIFF

).– Cut, copy, or mix sounds together.– Change the speed of a recording.

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– Sound editors cut layers of special effects, place sounds at certain times, cut out unwanted stuff and mix in interesting sounds. Cut pieces of vocals away or shift them to a another spot in a song.

– Editing is about cutting, placing, fading, cross-fading, shifting, duplicating, mixing and adjusting the volume (also referred to as level) of audio material.

Editing Digital AudioLab#7

Editing Digital Audio Lab#7

• Tracks - Tracks are individual pieces of audio. They can be either stereo or mono.

• Stereo - Stereo refers to a track where there are two channels that are distinctly different. It will appear as one track, but with two waveforms in it.

• Mono - Where a single track is distributed to both channels.

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How is sound represented? Lab#7

• Sounds are pressure waves of air.• There are two common types of sound wave:

– A single pressure wave that caused by a short event and quickly dies out. (a hand clap)

– A periodic wave which is a pressure waves from continuous vibration. ( bell ring)

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How is sound recorded digitally? Lab#7

• Recording onto a tape is an example of analog recording.

• Audacity deals with digital recordings.

• Digital Recordings: recordings that have been sampled so that they can be used by a digital computer.

• Digital files can be copied as many times as you want, with no loss in quality, and they can be burned to an audio CD or shared via the Internet. It can also be edited much more easily than analog tapes.

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The Audacity Interface Lab#7

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Main Toolbar Lab#7

• Importing first track

• Time Track:– It controls

the playback speed within a given range.

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Changing The Rate Lab#7

Set Rate: Set the sample rate of the track.

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Main Toolbar Lab#7

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Selection Tool

This is the main tool you use to select audio. Click in a track to position the cursor, or click and drag to select a range of audio. If you drag from one track to another, you can select multiple tracks.

Playback will always begin at the position of the selection cursorEnvelope Tool

The envelope tool gives you detailed control over how tracks fade in and out. When the envelope tool is selected, the amplitude envelope of each track is highlighted in a green line, with control points at the beginning and end of each track.

Main Toolbar Lab#7

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Time Shift Tool

This tool allows you to change the relative positioning of tracks relative to one another in time.

To use this tool, simply click in a track and drag it to the left or right.

Zoom Tool

This tool allows you to zoom in or out of a specific part of the audio.

To zoom in, click anywhere in the audio. To zoom out, right-click or shift-click

Main Toolbar Lab#7

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Draw Tool

Enables the user to draw in to the actual waveforms.

Cursor to Start Places the cursor at the start of the project.

Play Button

Press the play button to listen to the audio in your project.

You can also hit the spacebar to start or stop playback. Playback begins at the current cursor position. If a region of audio is selected, only the selected region will play

If there are multiple tracks in your project, they will be mixed automatically for playback.

Main Toolbar Lab#7

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Record Button

Press the record button to record a new track from your computer's sound input device. Use the Preferences to configure the recording options. In particular, there is an option to play the other tracks while recording. Recording always happens at the project's sample rate.

Pause ButtonWill pause during playback, or during recording. Press again to unpause.Stop ButtonPress the stop button or hit the spacebar to stop playback immediately.

Cursor to EndPlaces the cursor at the end of the project.

• Work individually and do the following:• Install Audacity audio editor.• Get Tracks 1, 2 and 3.• Import these files into Audacity one at a time.• Play tracks 1 and 2. You should hear printer laser audio in mono

channel, and phone ring in stereo channel.• Split track 2 into two mono channels.• Edit the phone ring sound; make it long as the printer laser sound

BUT without missing any ring ( reduce the time but keep the three rings) and without changing the speed of the sound.

• Shift track 3 to begin with the second ring. Use the time shift tool.• Decrease the speed of the sound in track 3 (make it slower)• Save your project then export the file into mp3 format. Name it

Lab7_Evaluation.mp3 IT342 13

Evaluation1:

Editing Digital AudioLab#7