Audacity is a free audio editor that's available for Windows, Mac OS and Linux. It lets you record sound - from a microphone, say, but you can also use it to record and convert old tapes or LPs to MP3 or other digital formats.
Naturally, Audacity also lets you edit existing MP3, WAV, AIFF and Ogg Vorbis files: you can cut sections, amplify, remove noise and apply effects, such as fade-ins and fade-outs.
That makes it ideal for editing podcasts (it even supports auto-duck) and if you have the right hardware, it can even record multiple channels at once.
Here we'll show you how to get to grips with Audacity, including downloading extra codecs so you can save your edited audio files in MP3 format.
First, download Audacity and install it. We're using Windows here, but it's the same on macOS or Linux.
How can I edit audio with Audacity?
Start by opening an existing audio file. The easiest thing to do is to go to your Music folder and open an MP3 file. You'll see the blue waveform (two waveforms if it's a stereo track), a time scale along the top and playback controls.
Let's fade in this track because we don't want it to start loudly. The selection tool (the same icon as used in Microsoft Office) is on by default. Click and drag a selection from around the five second mark back to the start of the track. From the Effect menu, choose Fade In.
How can I save as MP3 in Audacity?
To save your edited track, click File then Export… Choose Export as MP3. You'll then see a message saying Audacity can't locate lame_enc.dll. Click the Download button and your browser should open with instructions on how to download and install the MP3 encoder for your operating system.
Once you've installed Lame return to Audacity, click the Ok button from the dialogue box which popped up to tell you that lame_enc.dll was missing. Now repeat the save process, this time entering or editing the metadata when prompted (but note that you do not have to fill this out).
This time, when you click save, the file will save as MP3 because Audacity will find the encoder this time.
How can I record audio in Audacity?
If you have a microphone, you can record live audio. First, make sure your microphone is selected using the drop-down menu (you can change whether to record in stereo or mono using the other drop-down to the right). Click File, then New and click the round red record button.
How to make an audio file louder
If your recorded audio is too quiet, you'll see this as a narrow waveform which doesn't reach the top and bottom of the scale. You can amplify it by pressing Ctrl-A to select the whole track. Now choose Amplify from the Effect menu. The slider will be set to the maximum value possible without clipping, but you can override this using the checkbox.
How to remove hiss from an audio file
Most audio recorded on a microphone will have some background hiss. To remove noise, first select a silent portion of your recording a few seconds long. It's easier if you first zoom in: click the magnifier and select a section. This will then fill the screen.
Switch back to the selection tool and highlight a couple of seconds of 'silence'. Now choose Noise Reducation from the Effect menu. In the window that appears, click Get Noise Profile. Launch the Noise Reduction tool again and click Preview to listen to the result. You can use the sliders to tweak the filtering.
You might want to change some default settings, so click Edit and then Preferences. Under devices you can choose which playback and recording devices to use. Click Quality and you can choose the default sample rate for recordings.
To set the default quality when exporting MP3 files, click File > Export > Export as MP3. At the bottom you can set the bitrate and whether it's constant or variable.