WAVs and MP3s and AACs, Oh My! What Audio File Format Should I Use For My Podcast?
Have you ever been confused by the different audio file formats? Why is there such a variety of formats and why in the world do you have to choose?
Wouldn’t you rather just know which one to use, and be done with it?
Well I wish I could tell you that you only need one but the truth is that they exist for different reasons and it’s best if you simply know the difference. There are good reasons to use different formats at different times.
However, don’t despair, Ill explain a few here and help you to know the difference! you don’t have to be confused or frustrated any longer!
Some of the most common audio file formats:
Lossless Audio File Formats
- Apple Lossless or ALAC
- MOV (I include this because it’s what ECAMM Call Recorder creates)
Lossy Audio File Formats
- MP3 (or M-PEG. (Common format and plays in all players, Mac or PC)
- AAC (Common in iTunes)
- WMA (PC only. Not Mac friendly)
- OGG (I have only run into this on my phone)
The first group of file formats are called lossless formats, and are equivalent to being CD quality. The WAV format (or Waveform Audio File Format) was created for audio on PCs. It is the same as an actual music CD (Compact Disc), 16 bit 44.1KHz. And a WAV file can be considered the highest quality format for creating your podcast.
Many audio apps use WAV file formats now for the audio while you working inside the app (However It used to be that each app required its own proprietary format).
You can in fact create WAV files that are even higher quality than CD. When I record into Protools for example I will usually start by creating a session with settings of 24bit 48KHz and work at that resolution until it’s time to mix down my podcast. This is a habit I have formed from creating music and probably higher resolution than I really need for my podcast edits.
I will start out recording with a larger WAV file in my audio app and then at mixdown convert it to a smaller MP3 for uploading to my podcast host, Libsyn.
The last lossless file format to mention is the MOV file. ECAMM This is what Quicktime uses on a Mac, and is also what ECAMM Call Recorder creates when you record your Skype call. So you may run into this if you are conducting interviews on Skype. This file format is not really an audio format but is video with audio included.
When you record with ECAMM to MOV you will then need to use the Movie Tools afterwards to get your recording converted into individual tracks to import into your editing app. If you choose AIFF you will keep the resolution lossless as you convert. If you choose MP3 you will be converting the file down to a smaller compressed size and lose a little quality.
My feeling is that the loss converting to MP3 with the Movie Tool is so minimal that you don’t need to worry about it too much. The key is that if you convert to MP3 using any other app don't select setting lower than 128kbps to avoid any audible audio quality loss along they way.
Record as a WAV file and edit your podcast till it’s time to mix down and export
Then export as an MP3 and upload to the internet for publication and sharing
In fact if you only ever considered two file formats from here on out, WAV and MP3, you would have enough understanding to create your podcast and never look back.
But if you want to understand some of the other formats then read on read on…
The AIFF file or Audio Interchange File Format was created for the Mac and is also a lossless format. So if you have a file as a WAV or an AIFF then you can rest assured that you have a high quality file. If your audio app will work with an AIFF then go ahead and use that or convert it to WAV. Two other lossless formats you may run into are FLAC and Apple Lossless or ALAC. Both of those offer lossless compression for audio files that promise smaller file size at CD quality resolution.
A great tool for converting audio files on a Mac is the app Switch which you can download from the Softonic site (Safe according to Norton)
The next category are the Lossy file formats. These have been created to offer compressed versions of audio that result in much smaller file sizes to their CD quality counterparts. An MP3 for example creates an audio file that is slightly lower in sound quality to the original sourced WAV file. You can take a WAV file and compress it into an MP3 using a variety of apps to make the final file size much smaller. iTunes has this capability built right in (so do Protools, Logic, Studio One, and Audition) or you can download a separate app to convert the files.
Apps like Switch for Mac will also allow you also batch convert a group of files which can be a time saver when you want to start the process and go have a coffee break while you wait.
When you convert to an MP3 or even export your mix you will have the option to choose the compression settings for the MP3.
I find that setting it to 44.1Khz and 128kbps gives me an MP3 that sounds great when I listen back from the internet. This is the format I choose for my podcast.
(Bear in mind that these setting are great for exporting a podcast, but I would choose a higher setting for exporting music.)
When you export your podcast to MP3 or convert a WAV to MP3 you can feel confident choosing 44.1 and 128kbps.
If you don’t need to choose stereo to accommodate the music in your podcast then you can choose mono when you export your mix to make your file size half as big as stereo. All the voices should probably be mono anyway. Mono means centered in your speakers and not panned to the left or right.
Choosing mono can also make your podcast louder though so watch that your levels don’t get too high and distort the final result. If they do simply back down the output of the master fader when you mixdown your podcast from your audio editing app.
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