A few weeks ago my laptop crashed. At first, I wasn't too concerned. I have been using computers for 30 years, and I have learned a few tricks and tweaks to get a machine up and running again. It was only when my tricks and tweaks didn't work that I became concerned. The hardware it turned out was fine. Everything else, not so much. After reinstalling the operating system, I was left with a blank canvas on which to create a new system.
Audacity is an open source, multi-track sound recorder and editor available on Windows, Mac and Linux platforms. I had started using Audacity prior to my laptop's demise and resurrection, so it was one of the first applications I reinstalled once my machine was off life support. Ironically, one of few things I lost in the ordeal was the original version of this article. So without further discussion, let's look at the guts of the thing.
Audacity's user interface can be broken down into three basic areas: toolbars, menus and tracks. Each area has some unique functionality and some functionality which overlaps other areas. There are also keyboard shortcuts available for many functions, but a discussion of these is outside the scope of this article.
Audacity has eight available toolbars:
The Control Toolbar contains the six transport buttons used to control recording and playback: Pause, Play, Stop, Skip to Start, Skip to End and Record. The buttons are large and use standard symbols to indicate function. If any user is unsure of what the symbols mean, holding the cursor over the button will bring up a balloon with the function spelled out. Balloon help is available for all the buttons on the user interface.
The Device Toolbar allows the user set the input and output devices.
The Edit Toolbar provides the usual Cut, Copy and Paste functions. It also has buttongs for Trim which eliminates everything outside the current selection, and Silence which replaces the current selection with silence. The Edit Toolbar has buttons for Undo and Redo. It also has Zoom In, Zoom Out, Fit Selection on Screen and Fit Project on Screen.
The Meter toolbar provides metering for the stereo inputs and outputs. Meters can be horizontal or vertical. The display can be set to either linear or dB. The user can set how frequently the meters are updated to prevent any adverse effects on sound quality on slower machines.
The Mixer toolbar allows the user to set the levels for input and output
The Selection toolbar provides several functions. It displays/sets the current position in the audio file. It displays/sets the start and end points of the current selection. Optionally it can display the length of the selection instead of the end point. Position, start, end and length can be displayed in variety of formats including hours:minutes:second, samples, film frames, NTSC frames, PAL frames, CDDA frames and combinations of the above. The Selection toolbar also displays/sets the sample rate for the project as a whole irrespective of the sample rate of individual tracks.
The Tools toolbar provides the following functions:
The Selection tool allows the user to select a portion of audio track using the mouse.
The Envelope tool allows the user to draw an envelope to control the volume of a track.
The Draw tool allows the user to redraw the audio down to the individual sample.
The Zoom tool allows the user to use the mouse to zoom in on specific areas of audio.
The Time Shift tool allows the user to shift the selected track forward or backward within the project.
The Multi-tool combines the selection, envelope and zoom functions.
The Transcription toolbar allows the user to speed up or slow down playback to ease the transcription of difficult passages. The toolbar uses a slider to control the playback speed. This slider is not terribly accurate, however double-clicking on the toolbar brings up a window where the user can enter a precise factor to increase or decrease speed.
One of the cooler aspects of Audacity is its track display. In addition to audio tracks, Audacity supports label tracks, time tracks and MIDI tracks.
Label tracks allow the user to document a project. Selections can be named and saved. The labeled areas can be used to recall selections at a later time. There are other functions which use Label tracks which will be described in the Menu section.
Time tracks control playback speed. While the Transcription toolbar can be used to playback the entire project faster or slower, it is not saved with the project. The Time track is saved as a part of the project. It also allows the user to specify different tempos for various parts of the piece, and to transition smoothly from one tempo to another.
MIDI tracks exist in Audacity, but they have limited usefulness. They can be imported into the project and displayed in a piano roll format. They can't be played back and they can't be edited. The only real use I can see is they can be used to coordinate audio with MIDI events.
As you would expect, Audio tracks have a few more bells and whistles than the others. First of all, they can be either mono or stereo. The display defaults to showing the standard waveform showing the amplitude of the waveform over time. The track view has several other display options as well. It can show the waveform using logarithmic units instead of linear. It can show the frequency spectrum with either linear or logarithmic units and it can attempt to display pitch. The display can zoom in and out both horizontally and vertically. Tracks can be shifted forward and back in time as well.
The user can split a stereo track into two mono tracks or combine two mono tracks into a stereo track. Mute, Solo, Level, and Pan Position are displayed and can be set directly from the display. The display shows Stereo/Mono. Sample Rate and Sample Format. A drop-down menu allows the user to change the Sample Rate and Sample Format. Sample Rate can be set to any standard rate from 8000 to 96000 Hz. The Sample Rate can also be set to an arbitrary value between 1 and 100,000 Hz. The Sample Format can be set to 16-bit PCM, 24-bit PCM or 32-bit Float.
The Audacity's menus are well laid out with all the functions you would expect and perhaps a few you wouldn't. Rather than go into detail on the standard functions, I will try to hit some of the highlights of the other features Audacity provides.
Under the File menu, there are some interesting export functions. Import and Export under Audacity support a wide variety of file types and variations. Of course the popular file types are supported: WAV, AIFF, MP3, FLAC and Ogg Vorbis. In addition, less common types can be supported by specifying header type and encoding scheme. Headers include AU, AVR, CAF, MAT4, MAT5, VOC, etc. Encoding includes PCM, DPCM, ADPCM, 32-bit float, 64-bit float, U-Law, A-Law and more. If you can understand those last two sentences, more power to you. I can deal with WAV and MP3 and rest is for someone with requirements far beyond my own.
Export can operate on the entire project or only on a specific selection. There is also an option to export the labels to a text file. It saves the text of the label with the start and end points. There is also an Export Multiple function. This allows the user to export a project as a series of files. The series of files can be the individual tracks or the audio defined by the labels on the Label tracks. The former would be useful to move a project to another multi-track audio program. The latter would be useful for exporting individual hits from a drum loop for use in a drum machine program.
Audacity doesn't have a full macro capability. It does have what it calls Chains. A Chain is a list of functions that can be applied to the current selection. When setting up a Chain, certain parameters can be specified for most functions. So if have a long list of files where you want to normalize a piece of audio, remove any silence at the beginning and end of the file and then run it through a compression algorithm, setting up a Chain can be effective way to simplify that process. The Chain functions are also on the File menu
Under the Edit menu in addition to Cut, Copy, and Paste functions, there are a series of Split functions. Split functions separate the current selection into a separate piece of audio before performing the selected operation. What this means in practical terms is, say, the Cut function places the selection on the clipboard, removes the selected portion of audio and closes the hole. Split cut leaves the hole filled with silence. Split New removes the selection and creates a new track with the selection aligned with its original position in the project.
Also on the Edit menu are a series of functions which can be performed on the regions defined on the Label track. These include functions like Cut, Split Cut, Copy, Delete, Split, etc. Labeled regions can be saved and restored. Also playback can be locked to a given region. All these functions are useful when dealing with subsections of a larger audio file.
Under the View menu is a history function. It shows a list of commands that have been executed on the current project. It can be used to undo or redo multiple functions at a time. It would have been very useful if it were possible to copy these commands to create a Chain, but unfortunately that functionality isn't there yet.
The Tracks menu is were the user can create new tracks, remove tracks, align tracks, and sort tracks. In addition, there are other useful functions like converting stereo to mono and mixing down the tracks to a single track. This menu also has functions to create a Label for the current selection or at the current audio position.
The Generate menu has all the functions for creating sound. Included are functions like Chirp, Noise, DTMF (telephone touch tones), Click Track, Silence and others. Other generate algorithms can be added through plug-ins. Plug-ins will be discussed in a minute.
For me the most useful functions are found on the Effect menu. These functions include EQ, Noise Removal, Compression, Fade In, Fade Out, Change Pitch, Change Speed among many more. As with the Generate menu, additional functions can be added through plug-ins. In general the effects are well executed. For example, our esteemed leader at Muse's Muse, Jodi Krangle uses the noise reduction to good effect on her voice-over recording.
The Analyze menu has functions which can greatly improve the quality of a recording. Beat Finder and Silence Finder have obvious uses when dividing out pieces of an audio recording. Find Clipping will alert you when sound is being distorted. Potentially the most useful function is the Plot Spectrum. It provides frequency analysis with a number of different options. I would lying if I told you I understand everything this function provides, but I can read it well enough to understand where each track sits in the frequency spectrum and how that will affect the EQ and Level choices I make. In the right hands, I suspect a whole lot more could be done with it.
There is a Help menu, but the help files need to be installed separately. In all honesty, I never actually figured out how to do that. I use the manual which I keep on my machine, and that works well enough for my purposes. If you are set on having the help files, I am sure there is information on the Audacity web site which can help you.
As promised above, it is time to discuss plug-ins. As you probably know by now, plug-ins extend the functionality of an application. In Audacity, plug-ins can add new Generate algorithms and new Effects. Audacity supports three kinds of plug-ins: LADSPA, Nyquist, and VST.
LADSPA plug-ins were originally developed for Linux, but they work fine on Windows and Mac. On the Audacity web site there is a download with 90+ LADSPA plug-ins. It includes a lot of nice filters and other effects, but I have to admit I don't have any idea what some of them do.
Nyquist plug-ins are text based so no special software is necessary to create these, plus they work equally well on all platforms. Several are included with Audacity. For the more ambitious among you, there are tutorials available on line that describe how to write them.
If there is one area where Audacity disappointed me, it is in its support for VST. I am big fan of VST plug-ins and I have quite a collection. Since this is an audio editor, I wasn't expecting the VST instruments to work, but I had high hopes for the VST effects. Effects are supported, but only to a limited degree. The big disappointment is the effect's user interface is not displayed. What is displayed is a screen with sliders for any parameters that are exposed to host program, in this case Audacity. There is a list of VST plug-ins on the Audacity web site which have been tested and work well. Many of these are free and available on the Internet at sites like KVR Audio and Hitsquad.
I have been using this program for a couple of months now and as I have indicated above, there is very little to complain about. It is easy to use. Everything is well laid out. Functions are where I expect them to be. My learning curve was minimal. I am using the Beta version (1.3.5) which has more functions than the stable version (1.2.6), still I have yet to run into any defects or problems. If you use the Beta version, I recommend saving your work at regular intervals, but you should really be doing that anyway. Right?
Audacity isn't going to make high-end products like Soundforge obsolete. It simply doesn't have the depth of functionality or the flexibility of the more expensive products. Audacity is open source so it has been created and maintained by a group of people who work on a volunteer, ad-hoc basis. Documentation is adequate but not exceptional or even very robust. All this aside, if you need an audio editor and finances are an issue, download and install a copy, then give it a test drive. Unless your needs are quite demanding, Audacity should give you all the functionality you need.
Audacity's web site can be found at: http://audacity.sourceforge.net/