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Audacity: RecordingASound

Recording a sound

Software name : Audacity
Software version : 2.2.1

Recording sound with Audacity is very straightforward: you just need to have a computer that has a sound card with at least a microphone (mic) or line input.

Getting started

Before making a recording you need to make sure that the device you want to record from is connected to the audio input of your computer's sound card.  To do this you can use your computer's sound control panel or the custom mixer application for your specific soundcard, selecting the input device you want to use and verifying that you are getting sound into the computer from that device.  Note that you can also use Audacity's own Recording meter to test whether your desired recording device is inputting properly, and at appropriate levels.  However, and especially if this is your first attempt to record, it is preferable to first use your OS control panel or sound card's mixer application to verify audio input connectivity.  Then you can launch Audacity.

MacOSX Recording Configuration

[editor with Mac: please confirm whether these Mac-specific steps are still necessary.  The current Audacity documention suggests to me that this is not the case, and Mac users can configure in the same way as other OS users.  But I don't have Mac access to test this] 

OS X has a unique way to configure the audio hardware, which is not shared by other operating systems (Windows, and Linux). So if you use OSX you will need to make sure that it is set up appropriately. To do this first open the "Preferences" window by clicking on "Preferences" under "Audacity" in the Menu Bar :


The Preferences window open and look something like this:


Click on "Audio I/O". The use of "I/O" means "Input or Output", so "Audio I/O" means "Audio Input or Output". The Audio I/O preferences page is where you can choose the sound source  (audio input) and how you play back the sounds so you can hear them (the output settings). This can turn into a jungle of terms but essentially these things are the same:

  • input
  • sound source
  • audio input
  • input device
  • recording device

and these are the same :

  • output
  • playback device
  • output device
  • sound output

The way you configure the input effects how you will record sounds. The configuration of the output effects how you will play back sounds so you can hear them.

Lets start with the output settings, these are refered to within the "Playback" section. In the "Playback" section use the "Device:" dropdown menu to select the audio output you wish to use. Unless you have another sound card installed "Built-in Audio" will be the only option available.  


The input settings are chosen from the "Recording" section. In the "Recording" section use the "Device:" dropdown menu to select the audio input device you wish to use. Unless you have another sound card installed "Built-in Audio" will be the only option available. 


In the "Recording" section use the "Channels" dropdown menu to select the number of channels you wish to use. A "Channel" (also known as a "track") refers to the number of audio signals you wish to use to record or playback. A mono recording uses one audio signal (1 channel), and a stereo recording records two audio signals (2 channels).

Audacity defaults to "1 (mono)" so you can leave it at this if you are recording from a mono audio input. Most microphones are only capable of producing a mono signal.  Select "2 (stereo)" if you are recording from a stereo audio input such as a cassette or mini disc player (or a stereo microphone). It is possible to select up to 16 channels but do not select more than 2 unless you have something other than a 'normal' sound card.

Below the "Playback" and "Recording" sections are three check boxes.


The first check box is not important for this exercise because we are only recording one channel. If you want to listen to the sound as you are recording it you will need to have either "Hardware Playthough" or "Software Playthrough" ticked. "Hardware Playthrough" lets you hear the sound directly from the input source while "Software Playthrough" lets you hear the sound as it will be when the recording is played back.

Now click on "Quality" to bring up this page of preferences:


For this exercise you only need to worry about the first two settings; Default Sample Rate and Default Sample Format. Unless you really know what you are doing, use the dropdown menus to set Default Sample Rate to "44100 Hz" and Default Sample Format to "16-bit". This will give you CD quality recording.

Those are the only preferences you need to adjust before beginning to record so click "OK" to save the changes and close the Preferences Window. Audacity remembers these preferences so the next time you go to make a recording you will not have to repeat the steps above unless you wish to make changes.


Windows and Linux Recording Configuration

Windows and Linux use the same controls, and these can be accessed entirely from the Audacity GIU. First you need to choose the input device. As we saw in the Toolbars chapter, the Device Toolbar is where you select your desired Recording Device (second dropdown), as well as desired Audio Host (first dropdown: for Windows the options will be MME, Windows DirectSound and Windows WASAPI-- see Device Toolbar for more detail on these options).  Here you can also select whether you want Mono or Stereo recording (second dropdown):


Testing Audio Levels

Now that you have everything set up and ready to go you can begin the recording process. 

Before making the recording it is important to preview the loudest section of the source audio so that you do not end up with a distorted recording.

For this you will use the Recording Toolbar and Mixer Toolbar, as detailed in the Toolbars chapter:

The recording meter here will automatically be activated when you begin an actual recording; but since in this case you want a preview, simply click anywhere on the meter to activate monitoring.  Now play the loudest passage of the audio you want to record and, while doing so, look at the recording meter:

At the loudest point in the audio, the green bar should ideally stretch all the way to around -9 dB (decibals); it's tip wil turn yellow between -9 dB and -6 dB, which is a warning margin, and will turn red just before -3 dB (which indicates that your input is is too loud or 'hot', and may be clipped by Audacity).  Adjust the input/record slider of the Mixer Toolbar downward (toward the minus) if you see any red or much yellow; adjust the slider upward if your maximum input or 'peak' is far short of -12 dB.  

While an ideal input level peak is between -12 dB and -9 dB, if you have difficulty hitting this target zone with input slider adjustments, it is better to err on the side of too little recording input (not green all the way to -12) as opposed to too much (a red tip).  The output volume of a quieter recording can always be boosted in a subsequent editing stage; but a too-loud recording will be 'clipped' by Audacity, meaning it is too loud for Audacity to process and the top and bottom of the wave-form will be chopped off, thus losing some of the recorded wave information. 



Now that you've tested your input device and recording levels, you are ready to make your proper recording.

Click the "Record" button on the Transport toolbar:

then play the audio you wish to record. Once the sound source has finished click the "Stop" button:

Your recording is now complete. It should appear in the Audacity GUI as a single audio track, showing either a single channel (if you've chosen mono recording) or dual L/R channels (if you've chosen stereo).  Here I have made a stereo recording of a simple chord riff on accoustic guitar, from my built-in computer mic:

Note that the "Project Rate (Hz)" dropdown on the bottom left indicates that I have made my recording at a sample rate of 44100 Hz (44 KHz).  This sample rate is compatible with traditional music-CD sound quality, and is the defaut for Audacity's recording mode.  However, in the dropdown I could set the rate to as low as 8 KHz or as high as 384 KHz (which would produce a very high-fidelity but very large sound file).


Now listening to your recording with the Play button on the Transport toolbar:

If you are not satisfied with the recording, you can delete it from the project using the X in the upper left corner of the track bar (or by going to Edit > Delete in the main menu).  However, before discarding a recording completely, you will want to consider whether it can be edited or otherwise modified, using Audacity's multitude of tools, to bring it closer to what you had in mind.  Only experimentation and practice will help you decide whether to aim for perfection in the recording itself, or edit it after the fact.

If you decide to save the recording, do so by selecting "Save Project As" from the "File" menu (this will save the wave form as is, including all separate tracks in the project, allowing you to come back later for editing and export).  As this is a new project, you will be prompted for a Project name as well as the location to save the Project file:


That's it! Your recording is completed and saved. If you want to access this project again for editing and/or export to a common audio file format such as MP3, use File > Open (not Import, which will not work with Aup files) and browse to the location of your saved Audacity project.


Troubleshooting - Linux

Linux :: Host Error?

If you are a Linux user and you see a message similar to this  "Error Initializing Audio: There was an error initializing the audio i/o layer. You will not be able to play or record audio. Error: Host error." then you may have to try one of the following :

Kill esd 

It maybe that the esd sound server is running which is not permitting Audacity to access the sound card. You can try running this in a terminal:

ps ax | grep esd

If you see an output similar to this :

5164 ?        Ss     0:00 /usr/bin/esd -terminate -nobeeps -as 1 -spawnfd 18
10352 pts/1    R+     0:00 grep esd

Then you can see from the first line that esd is running ("/usr/bin/esd"). To kill the esd sound server you need to type this in a terminal (you need to have the permissions to run the sudo command) :

sudo killall esd

You will then be prompted for a password, enter your password not the superuser password (also known as the "root" or "admin" password). Then try and start Audacity again, hopefully you won't get this error.

Start with aRts

You could also try running Audacity through the aRts sound server ("analog Real time synthesizer").  To do this quit Audacity if you already have it opened and restart it with this command in a terminal:

artsdsp audacity


Kill aRts

Lastly, you may wish to try starting Audacity after killing the aRts sound server.  You can try this:

sudo killall artsd

Then try starting Audacity again.

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