Friday, January 30, 2015

WAV vs. MP3 Presentation

How do you explain a difficult concept to someone who doesn't have any background with that concept? Try comparing it to something they already know. This is called an analogy. In the Google Slide presentation that follows, I am trying to explain the difference between two different audio file formats, .wav and .mp3, to an imaginary 5th Grader.  Why to a 5th Grader? I want my explanation to be as simple as possible to understand.

Most people who listen to music these days probably don't even think of the difference between audio file formats–they just pop in their earbuds and start up their music on their phone.  The reason why Music Tech students need to know the difference between audio file formats is because there are different occasions when one might play a .wav file instead of an .mp3 file, or vice versa.

The two main differences between a .wav and an .mp3 file are the size and the quality of sound. When the Music Tech class exported a 38 second .wav file of their first Dance Project and imported it into iTunes, they could see the size of the file was around 6.6 MB (megabytes).  In iTunes, they converted the .wav file to an .mp3 file and the resulting size was around 768 KB (kilobytes).  In other words, the .wav file was about 8.5x larger than the .mp3 file (encoded in iTunes at high quality, 160 kbps).  So it is easy to see that a .wav file is much larger that an. mp3 file.

The audio quality is much harder to differentiate between the two file formats for one reason: most consumers of music today listen to music on either earbuds or headphones, not on large sound systems.  The audio information that was lost through compression of the .mp3 file is very hard to hear on small speakers like earbuds or even over-the-ear headphones unless you know what to listen for.

I used to think it was the bass "punch" that was lost in the compression of a .wav file to an .mp3 file, until two students stumbled across two different YouTube videos which tried to show the difference: Ryan Boelk and Kayla Holst.

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