From Fedora Project Wiki

< User:Crantila‎ | FSC
Revision as of 06:49, 17 July 2010 by Crantila (talk | contribs) (added instructions for further revision, as per IRC reviewer in #music)

This page is a draft only
It is still under construction and content may change. Do not rely on the information on this page.

Address: User:Crantila/FSC/Recording/Audacity

Introduction

There are no clearly-defined roles that Audacity can play. Once you have used the program for a while, and especially if you become familiar with other audio-processing software, you will begin to realize that certain situations are more or less suited for Audacity's capabilites than others.

Audacity was designed to play the role of a simple, multi-functional, integrated audio editing program. It is less sophisticated but easier to learn than the other digital audio software in this Guide (Ardour, Qtractor, and Rosegarden). As such, it can be appropriately classified as an "Audio Editing" program.

If you have ever used a consumer-market audio recorder (based on either flash memory or tape), then you can think of Audacity as being roughly equivalent to those hardware devices. Audacity offers some additional features that make it more useful and flexible than those devices, and can therefore be used to do things which hardware recording and editing devices cannot.

Knowing When to Use Audacity

Audacity should be the program of choice for most people interested in recording audio. It is fast, flexible, and easy to use. It does not require advanced setup of audio hardware, or more than basic knowledge of audio recording techniques. It is capable of recording and producing audio files of the same quality as any other audio software. If you want to plug in the microphone, record, and export you work to show your friends, then Audacity is the program for you.

Ardour is an advanced recording program, requiring some specialized knowledge of audio hardware and recording techinques, as well as more intensive setup of system hardware. Ardour also has basic MIDI capabilities. If you are using audio with more than two channels, recording multiple tracks in multiple takes, and looking for the most fine-grained control of levels, panning, and your hardware, then Ardour is the program for you. Ardour must be used with JACK, and it is therefore recommended to also use a "real-time enabled" kernel (SEE SOME SECTION SECTION).

Qtractor and Rosegarden are both best-suited for work as MIDI sequencers, although they are capable of working with audio in ways similar to Ardour. Since Audacity is not intended for use with MIDI signals, users looking for this capability are encouraged to investigate the differences between these two programs, and choose whichever suits their needs.

!! link to "Which DAW to Use" !!

Requirements and Installation

Requirements

In addition to Audacity's files, the program requires the installation of several other libraries and applications. These will be installed automatically with Audacity, so there is no need to install them yourself. !! clear this up; focus on letting the reader know that the dependencies will automatically be taken care of !!

The JACK Audio Connection Kit is required by Audacity, even if you do not intend to use it. This software package is relatively large (at 11 MB), but is a requirement. If you have installed the Planet CCRMA repositories, and not already followed the JACK Guide's installation procedures, then you are strongly encouraged to do so immediately after installation of Audacity, for security reasons. An explanation and instructions are available here.

Installation

  1. Run su -c 'yum install audacity' or use PackageKit or KPackageKit to install the "audacity" package.
  2. Review the requirements list, and approve it.
  3. It is a good idea to test Audacity before using it for a real recording. If you don't test it first, then Audacity may not record what you want. !! explain why !!

Post-Installation Testing: Playback

  1. Locate an audio file that you want to use to test playback.
    • Files in *.WAV or *.AIFF format will be the easiest to use at this point.
    • The file should not be especially quiet; you should easily be able to know whether it is playing correctly.
    • The file can be located anywhere on your computer, as long as you have permission to read it.
    • If you do not already have a file, you can use /usr/share/sounds/alsa/Noise.wav, which is intended for test purposes like these.
  2. After starting Audacity, use the "Open File" window to find and select the file (in the menu, click 'File > Open').
  3. Play the file repeatedly, as needed. Adjust the volume levels on your speakers and audio interface, if necessary.
  4. If playback does not work as intended, first verify that your hardware is setup correctly. If it is, then verify that Audacity is setup correctly - see the !!"Configuring Audacity to Use Your Hardware" section!!.

Post-Installation Testing: Recording

  1. Set up your microphone (or other audio source) so that it is connected to the input of the sound card you are using.
  2. Start Audacity with an empty session (no audio file is open).
  3. In the toolbar, there should be two volume level meters.
    • During the playback test, one of them should display green bars.
    • The other one will display red bars, representing the input level from your audio interface.
    • If you do not see it, it may have been accidentally closed. You can ensure that it is displayed by using the menu, 'View > Toolbars > Meter Toolbar'. There should be an "x" next to it.
  4. There is a small, downward-pointing arrow next to the microphone icon on the level meter. Click the arrow, then choose 'Start Monitoring'.
  5. Ensure that your source is producing an audio signal. If your source is a microphone, then sing or talk into it.
  6. The recording level meter should react to the input.
  7. Press the "Record" button on the toolbar to start a test recording.
  8. After a few seconds, press the "Stop" button on the toolbar to stop the test recording.
  9. Press "Play" on the toolbar to start playing the test recording. The playback should represent the sound that you wanted to record.
  10. If recording does not work as intended, first verify that your hardware is setup correctly. If it is, then verify that Audacity is setup correctly - see the "Configuring Audacity to Use Your Hardware" section.

Configuration

The First Time You Use Audacity

When you run Audacity for the first time, you will be asked to select a language to use for the interface. Also, if you have installed the Planet CCRMA repositories, and have not already followed the JACK Guide's installation procedures, then you are strongly encouraged to do so before using Audacity.

Before recording for the first time, you are encouraged to test Audacity to ensure that it is set up correctly. SEE ABOVE.

Configuring Audacity to Use Your Hardware

Especially in cases where your computer has multiple sound cards, or where a single sound card provides multiple, independent input and/or output busses (streams), Audacity may not correctly guess which busses you want to use.

  1. After starting Audacity, open the "Preferences" window from the menu: 'File > Preferences'
  2. Choose "Devices" from the left tab-list.
  3. The "Host" should usually be "ALSA," unless you want to use Audacity with JACK.
  4. The right setting is for both recording and playback devices is probably "default."
  5. If "default" does not work, then the next best choice is any of the devices that have names ending with something like (hw0:0)
    • If you cannot make an educated guess, then try the devices systematically.
    • This connects Audacity to your audio interface(s) in such a way that PulseAudio will not be able to use the devices at the same time, but it gives Audacity the greatest amount of control.
  6. As a last resort, you can use the "pulse" devices, which connects Audacity to PulseAudio. Because Audacity does not have direct control of the audio hardware in this case, it can lead to poor performance.

Setting the Project Sample Rate and Bit Rate

The related concepts of "sample rate," and "bit rate," are explained IN THIS CHAPTER (Sound Cards). Audacity refers to "Bit Rate" as "Sample Format."

  1. After starting Audacity, open the "Preferences" window from the menu: 'File > Preferences'
  2. Select 'Quality' from the left tab-list.
  3. Select the settings that you wish to use.
    • CDs hold audio with a sample rate of 44100 Hz, and a sample format of 16 bits. This is sufficient for most uses.
    • Setting 96000 Hz and 24 bits should be enough for almost any use.
    • You should not provide settings that are greater than your audio interface can provide. It is probably not dangerous to do so, but it may decrease sound quality. If nothing else, it will use extra space on your hard drive, with no added audio quality.

The Interface

This tutorial could use a picture of the interface, with an explanation of what the buttons do.

Tutorial: Creating a New Login Sound

To follow this portion of the tutorial, it is strongly recommended that you download the Audacity working-file, and begin doing the actions described, as instructed in the tutorial.

Tutorial Files

The following files will be useful, if you choose to follow along with the tutorial. Only the "Starting State" file is necessary; the other two are provided as possible completed forms.

Scenario

You were telling a friend about Fedora Linux's open-source audio programs, and you mentioned that Audacity makes it easy to create and edit audio files. The friend reminds you of their long-standing desire to create a new sound to be played whenever they log in to their computer, and suggests that Audacity can be used to make just a sound. You decide to work on it together.

Inspiration

You choose a starting-point for your new login sound. After thinking about it for a while, you decide to record some clips from a CD that you own, and mix them together.

Starting Out

  1. Make sure that your system is set up to record (with hardware and sample/bit rates properly selected).
  2. You can use the level meter to monitor the input level. Before recording, you should test the input level, adjusting the audio interface as required.
  3. To begin the recording, hit the circular red "Record" button.
  4. When you have finished recording, hit the square orange "Stop" button.
  5. After recording a portion of audio, it should show up in the main portion of the window, with a blue, sound-wave-like shape representing the volume level of the recording.

Continuing to Record

There are three main ways to record something additional:

  1. You want to continue recording from the end of the already-recorded material.
    • Hold the 'Shift' key as you click 'Record'
    • Audacity will continue recording in the last-selected track, from the end of all already-recorded audio.
  2. You want to record something new to go along with what you already have, starting at the beginning.
    • Move the transport to the start: press 'Home' on the keyboard or from the menu, select 'Transport > Skip to Start'
    • The transport is the vertical line, which represents the place where Audacity will begin playback or recording if the 'Play' or 'Record' buttons are pressed.
    • When you click 'Record', Audacity will record onto a new track, and not erase what you have already recorded.
  3. You want to record something new to go along with what you already have, starting somewhere else.
    • Locate the place from where you want to continue recording.
    • Use the cursor to left-click on that place in an already-recorded segment.
    • When you click 'Record', Audacity will record onto a new track, and not erase what you have already recorded.

Aligning Tracks (audacity-1)

At this point in the tutorial, you can begin to follow along by modifying the Audacity working-file.

If you accidentally record something at the wrong time, or if you change your mind about when a track should be playing, you can easily move it.

  1. Select the "time shift tool" from the toolbar.
  2. Click on the track you want to move, then slide it left or right to adjust it as desired.
    • To align the start of one segment to the end of another, drag the later track so that its start is near the end of the earlier one; move it slowly around that area until a yellow line appears, showing that the segments are aligned.
    • To align a segment so that it begins at an arbitrary point, use the "selection tool" to move the transport to that point. Then, from the menu select 'Tracks > Align Tracks > Align with Cursor'
    • There are other alignment options in the 'Tracks > Align Tracks' menu, and they apply only to the currently-selected tracks. To select multiple tracks, click on the portion of the track at the left, which has information about it. Then, hold down 'Shift' on your keyboard, and select the others.
  3. Select the "selection tool" from the toolbar.
  4. Click to place the transport just before the splice, then press "Play" to hear it. Adjust again if necessary.

Stretching Tracks (audacity-2)

You can stretch or compress tracks, so that they take up more or less time. There are two tools which do this:

  • The "Change Tempo" tool, which adjusts speed but not pitch. This degrades sound quality quite a bit.
  • The "Change Speed" tool, which adjusts both speed and pitch. This does not degrade sound quality as much.

To stretch or compress a track,

  1. Select that track by clicking on the portion at the left, which has information about that track.
  2. From the menu, select 'Effect > Change Tempo' or 'Effect > Change Speed'.
  3. Use the window to adjust the degree of stretching/compression:
    • Positive values increase speed and compress the audio.
    • Negative values decrease speed and stretch the audio.
  4. You can use the 'Preview' button to get an idea of the speed change that will happen with your selected settings.
  5. After clicking 'OK', it may take a few seconds for Audacity to process and apply the changes you requested.

Adjusting a Track's Volume and Removing Noise (audacity-3)

If you want to make a track louder or quieter, you can adjust the volume of individual tracks, or portions of tracks.

  1. The bottom-most track in the tutorial file is hardly audible. You press the "solo" button on that track to hear it alone, and realize that it's mostly very quiet humming.
  2. You use the selection tool to select part of the track.
  3. Use the menu to select 'Effect > Amplify', which is a tool that, in effect, adjusts the volume level of an audio segment. If you enable clipping, then you will be able to adjust the level much higher than if you don't. However, you may lose part of the audio signal, and the sound quality may deteriorate. You may have to experiment to find an acceptable balance.
  4. This track still has a lot of "noise," which was created by the recording tools, rather than what was supposed to be recorded.
    1. Select about a second of audio, which is going to serve as a the model of "noise" that should be removed. Ideally this portion of audio will contain only noise, and no signal that you wish to save.
    2. Open the "Noise Removal" tool by choosing 'Effect > Noise Removal' from the menu.
    3. In the "Noise Removal" window, click 'Get Profile', so that the tool will take the selected portion of audio.
    4. Now select the whole track, which is th portion of audio from which you wish to remove the "noise."
    5. Return to the "Noise Removal" tool's window, and select 'OK'.
  5. Now you realize that the end of the upper-most track is too loud, so it interferes with the otherse.
    1. Select the last two seconds of that track.
    2. Use the "Fade Out" tool, from the menu: 'Effect > Fade Out'
  6. You think that the third track's entrance is too quiet, so you select the first portion, then 'Effect > Fade In' (huh?)
  7. there's a bit of noise in the fourth track at about 13:00 that you want to bring out, so you amplify it (double-huh?)

Removing a Portion of Audio (audacity-4)

  1. The fourth track, after the noise-bump that we just amplified, is just noise. We don't need it, and it sounds strange, so let's take it out.
  2. Place the transport at the start of the segment that you wish to remove, by left-clicking in the existing audio track.
  3. From the menu, select 'Edit > Select > Cursor to Track End', which will select the portion of audio in the currently-selected track between the transport and the end of the track. There are many other options for selecting audio available in that menu.
  4. On your keyboard, press 'Delete'.

Repeating an Already-Recorded Segment (audacity-5)

While you like the beginning of the sound, the end doesn't seem "busy" enough. You decide to repeat a portion of the second track, to make it seem as though it "just won't leave."

  1. Use the cursor to select the last second of the second track from the top, then select 'Edit > Copy' from the menu.
  2. Place the transport arbitrarily, later in the track, and choose 'Edit > Paste' from the menu. Repeat this, so there are two copies.
  3. Select the 'Time Shift tool' from the toolbar, and adjust the time of the two copied segments as desired.
  4. You might also wish to adjust the volume of a segment, depending on whether it sounds too loud for you.

Add a Silly Effect: Using the Phaser (audacity-6)

!! make it more clear that this is supposed to show the various effects and plug-ins available; consider explaining what the Phaser settings do !!

!! maybe link to a page which explains what the most popular effects/plug-ins do !!

The third track has a significant portion of audio after the end of every other track. You decide to experiment with a tool called "Phaser", so that you can make it more interesting.

  1. Select the portion of the third track which begins after the last occurence of the second track, and goes to the end. There are a few different ways to do this.
  2. From the menu choose 'Effect > Phaser', and experiment with the settings. Use the 'Preview' button to sample the outcome of your currently-selected settings.
  3. You can use whatever settings seem appropriate. The tutorial file uses these settings: 
    Stages: 2
Dry/Wet: 128
LFO Frequency: 0.4
LFO Start Phase: 0
Depth: 128
Feedback: 90

Further Comments

If you followed along with the Audacity working-file, the chances are that your result is different from the completed model available above. There are a few reasons for this:

  • The tutorial's instructions are intentionally vague. This allows you to easily see how they apply to different uses.
  • The tutorial's instructions allow room for creative experimentation. This allows you to create a different result from the same starting material, by harnessing your own creative power.
  • While the model completion was being created, some extra steps were used to modify the sound. While the result was reached with all of the same tools and techniques described in the tutorial, they were used many more times than the tutorial explains. In particular, the tracks were time-shifted between most steps.

Saving and Exporting

When you save a file in Audacity with the "Save" or "Save As" commands, it is saved in an Audacity-only format. This is good, because it allows Audacity to save extra information about the audio, which is impossible to store in conventional formats like OGG, FLAC, or even AIFF and WAV.

If you want to share your audio work, or use it with another application, you will need to "export" it. This means that all of your tracks will be reduced to one track, and all of your channels will be reduced to stereo audio (with two channels). When you export, Audacity may warn you that your audio is being mixed into two channels. This will only affect the exported audio file, not the Audacity-format file.

Exporting Part of a File

  1. Use any means to select a portion of audio. You can click-and-drag with the cursor, or place the transport and use the 'Edit > Select' menu, or use another means.
  2. From the menu, select 'File > Export Selection'
  3. Use the "Export File" window to choose the format of your exported audio, and to configure advanced options of the format. Not all formats have advanced options.
  4. After clicking 'Save' in the "Export File" window, some formats will provide a window where you can configure "metadata" about the file. Metadata is information about information - in this case, it describes qualities about the audio in the exported file, like Artist, Title, Genre, and so on. You can leave the fields blank, or complete as many as you prefer.

Exporting a Whole File

  1. From the menu, select 'File > Export'
  2. Use the "Export File" window to choose the format of your exported audio, and to configure advanced options of the format. Not all formats have advanced options.
  3. After clicking 'Save' in the "Export File" window, some formats will provide a window where you can configure "metadata" about the file. Metadata is information about information - in this case, it describes qualities about the audio in the exported file, like Artist, Title, Genre, and so on. You can leave the fields blank, or complete as many as you prefer.
Retrieved from "https://fedoraproject.org/w/index.php?title=User:Crantila/FSC/Recording/Audacity&oldid=186739"