For many of the mobile apps we're developing at ReignDesign, we need to record MP3 audio files. Audacity is a great cross-platform tool for recording and editing sound files, but it can take some tweaking to make clear audio files. Here's seven steps to get you started.
1. Install Audacity
Download the appropriate installer for Windows, Mac or Linux from the Audacity site and install it on your computer.
2. Get the LAME mp3 plugin
For legal reasons, Audacity doesn't ship with a MP3 encoder. You need to download a separate file to enable exporting to MP3. Follow the instructions on the Audacity site to download the library. For example, on Windows, you'll download a file called lame_enc.dll. Audacity will prompt you to locate this file the first time you export as MP3.
3. Start Audacity
Make sure your headphones and microphone are plugged in, then run the Audacity program (in Windows, from your Start Menu). The main Audacity window will appear. Take some time to explore the menus and toolbars.
4. Record your audio
To record audio, just press the red record button. As you speak, you can see a waveform representing your speech appear on the screen.
If the recorded audio is too quiet, the waveform will be small like this. You can increase the microphone level by dragging the microphone slider.
If the recorded audio is too loud, the waveform will be clipped at the top and bottom, and you should reduce the microphone level.
It's easiest to record all your sound clips in one 'take', pausing a few seconds before each item. If you make a mistake, just repeat the clip (it's easy to remove errors in Audacity later)
Here are some more recording tips:
- Record in a quiet room.
- Make sure the microphone is not too close to your mouth.
- If you find that you hear a 'popping' noise when you say hard consonant sounds like 'P', you can try placing a piece of cloth like a scarf between your mouth and the microphone.
5. Check amplitude levels
Once you've finished recording, check the volume levels are not too loud or too quiet. Drag to select the whole audio file, then choose Effect > Amplify. By default, Audacity will choose the greatest amplification possible without clipping.
6. Remove background noise
Inevitably there will be some humming or background noise in your recordings. Luckily, Audacity provides a powerful tool for removing background noise. First, select a portion of the audio recording where you are not speaking
7. Export each clip as an MP3
Now you should have several clips separated by a few seconds of silence. Select a clip, and press space to preview. If you're happy, then go to File > Export as MP3... If this is your first MP3 export, you'll be prompted for the location of the file you downloaded in Step 2. Once this is set up, you can choose a filename for your exported MP3, and optionally set ID3 metadata, like title and genre.
And that's it! You can now include your MP3 files in your programming projects.