Audacity 3 (https://www.audacityteam.org)
Feel free to pick and choose from the general tips on editing mp3 files for a podcast below:
For sound engineering, I encourage you to record and post-edit your recording using the latest version of Audacity.
Post-editing a recording enables you to tidy things up. Cutting gaps, reducing the 'emms and ahhs', remove filler speech, background noises and any generally unnecessary audio. Audacity also lets you to record directly to the project if needed for voice over and bookend statements.
You can also post-process the recording to try to improve its quality; applying effects such as normalize (e.g. default values, typical -2.5dB) and compressor (default values), noise reduction, to fade in / fade out edits and eventually, and then ultimately, export the finished project to a new mp3 file.
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| A screen shot of an Audacity project |
The screenshot above illustrates what waveform levels might look like for your recording. Above all else trust your ears to judge the quality of a recording when you listen back to it.
Editing Audio for Podcasting with Audacity
Save Save Save - the Project file and folder
Everything lives in .aup3.
You are strongly advised NOT to save your active project to an external USB stick/disk, networked storage or cloud storage as it is unlikely to be fast enough for satisfactory recording and editing.
To avoid data loss save the project frequently. Make a local disk copy for project editing as Audacity generates very large sets of project edit/state files (online cloud drive services may not unpack or stage quickly enough to support Audacity's project edit/save cycle).
To share an Audacity project with others you will need to share the project aup3 file.
To share an Audacity project with others you will need to share the project aup3 file.
n.b. older versions of Audacity stored data in a project _data folder. If you move to Audacity 3 there will no longer be a _data folder for each project (yay).
Importing audio
Create a new project and save to disk.
File > Save Project > Save Project (cmd S)
Import previously recorded audio (an mp3 or wav file).
File > Import > Audio
Save
cmd S
Your Audacity project with at least one audio track will resemble the screen shot above.
You can play, pause and even record new audio to the current track.
The playhead is the vertical line displayed over the waveform. All tracks will play through the audio device unless muted or one is soloed. The keyboard space bar toggles the play/pause function from the current playhead.
Quick select, cut and paste
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| The Audacity toolbars, click and drag to rearrange or float |
Choose the Selection Tool (F1) to edit your audio track directly. Click-drag to highlight parts of the audio waveform. Use the cursor to select the waveform to copy (cmd C), paste (cmd V), duplicate (cmd D) cut (cmd X) or delete (del, backspace or cmd K) along the timeline. The edit commands are also accessed via the menu.
Edit > etc.
Using Tracks
Import a second audio file (for example, our intro/outro music).
Save the project (you should save frequently).
You will see at least two tracks in the current Audacity window.
Toggle the Sync-Lock Tracks setting if you want multiple tracks to overlay each other. This is useful if for example you want to overlap and slowly fade out an intro jingle.
Tracks > Sync-Lock Tracks (on/off)
You can organise the structure of a recording by using new tracks for sections of audio (to organise the large scale edit).
Large scale edit
Your listeners want a well edited informative podcast so remember, less is more. You will have to listen (and re-listen) to your material and decide what to keep or delete. Think about the length and structure of the recording. You can change the order. You will delete stuff so do it. Concentrate on large chunks, the structure of the talk. Don’t worry about breathing, coughs and minor noises just yet.
Small scale edit
After the large scale edit more or less done, spend time on the small scale edit. This involves zooming in and fine-grained cut and pasting. But think before acting, is it really necessary to remove every single intake of breath?
For example: cut long gaps, background noises and any generally unnecessary audio. You might also cut some of the egregious 'emms and ahhs' and nervous filler speech we all use. A caution though, the small scale edit can become a journey without an end, or at least a very long journey.
Note: "Sometimes you will not want to close the gap and yet still remove the noise, for instance if somebody breathes loudly. For such occasions copy a section of audio during which nobody is speaking (e.g. at the start of the recording) and paste it over the unwanted noise. This will preserve the natural pacing of speech." (source: Cook & Holdis, CEU Podcast Library - link)
Fade-in Fade-out
Apply fade-in and fade-out when you want the speech to start or end smoothly.
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| A useful Audacity EQ setting |
Post-processing - Graphic EQ (equalization)
Base boost plust treble boost
Post-processing - normalize
Apply default (-3dB) - the waveform will push over 0.5 but keep away from 1.0
Post-processing - compressor
Choose a threshold between default -12dB down to as low as -30dB
Select noise floor, around -50dB
Ratio, between 2:1 - 3:1 - 5:1
Drop attack time (0.2s) and release time (2.0s) to maximise compression applied
These settings end up boosting the volume (visually the waveform moves closer to 1.0) making it too loud and noisy so you'll need to normalize (or amplify) again...
Post-processing - normalize again
Apply default (-3dB) or you can apply Amplify -3dB, for the same result.
The desired result being for the waveform peaks to re-balance back to around the 0.5 level.
Post-processing - noise reduction (if needed)
Post-processing - low pass / high pass and other ways to reduce echo?
Export the mp3
Quality checks:
- Is the intro/outro music at a suitable level?
- Does the intro/outro transition smoothly to/from the spoken audio?
- Is the spoken audio at a suitable level? (i.e. no clipping, waveform amplitude averages around 0.5 on linear scale)
- Is the speed of speech natural?
- Large scale edit - remove fumbled speech, removed confidential disclosures, cut out a duplicate or passages that were off topic, etc.
- Small scale edit - remove ticks, emms, ahhs, sighs, distracting background, etc.
Useful links
An Audacity tutorial on mixing a narration with background music
https://manual.audacityteam.org/man/tutorial_mixing_a_narration_with_background_music.html
https://manual.audacityteam.org/man/tutorial_mixing_a_narration_with_background_music.html
Refer to the Audacity manual online (e.g. the track panel description/explanation is at manual.audacityteam.org)
An Audacity user's simple tutorial and workflow activities:
Using the Compressor in Audacity
Using Noise Removal in Audacity
On including music from other artists (for atmosphere, decoratively, for intros/outros & transitions)
In the first instance, if you know the artist ask for their permission to use their material. You may be pleasantly surprised by the positive cycle of recognition and community surrounding artist works. Make sure you acknowledge them in your show notes.
We recommend releasing under the “Attribution-NonCommercial-ShareAlike version 4.0 creative commons license (aka CC BY-NC-SA 4.0). You can choose from a number or variations of the CC license; CC BY, CC BY-NC, CC SA etc.
These licenses can be viewed at https://creativecommons.org/licenses/by-nc-sa/4.0
Always check the royalty free claims of audio samples found online. If you want to find audio from online sources, search for CC BY titles on Soundcloud or on YouTube
The link to the YouTube channel "Of Musicians" below is a collection of a selection of royalty free original music.
Record the following information in your show notes to establish the provenance and bona fides of 3rd party music, artwork and creative content that you decide to use:
Music (CC BY-NC-SA license)
Title: “a title”Artist: “a name”Source: “a link to the original”License: “CC BY-NC-SA”
Cover Art (CC BY-NC-SA license)
Title: “a title”Artist: “a name”Source: “a link to the original”License: “CC BY-NC-SA”
