Do I need to dither when converting to mp3?

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Is it necessary to use dither when converting a 24 bit song to 16bits before mp3 conversion? The short answer is no. I’m not going to go through the math to explain because the numbers are sound. I’m just going to explain it with simple logic and some audio clips.

The reason for saying no is simple, any benefits gained from bit reduction would be negligible due to the lossy encoding of MP3. Any distortion caused by truncation at the 16th bit, would probably not be noticible for two reasons:

1. The distortion would mostly likely be masked by the degradation caused through the MP3 encoding process.
2. Either way the effect of the dither will be un-noticeable except in extreme circumstances of bit reduction or in certain listening situations.

In addition here are some other factors to think about:

• Do you really think the end listener will really care about the sound quality of the song like you do? Will they be listening in the most optimal environment where they can hear and discern every single sonic nuance in the song? Most likely not.
• When was the last time you heard someone say, ” Man this album is awesome but they should have used Pow-r type 2 dither instead of UV-HR22. The poor dither choice has clearly ruined my listening experience.”
• Think about how many low encoded MP3s or streaming music you have heard online and how it has effected your overall listening experience.

Here are  audio clips I made of a few random apple loops in Logic and exported them out of Logic and used the POW-R type 2 dither on the files that were dithered. Then I converted the files to a 320KBPS MP3 using Compressor. Can you hear the difference between them?

1. 24 bit audio file converted to straight to MP3  

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2. 24 bit audio file dithered to 16bit then converted to mp3

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3. 24 bit audio truncated to 16 bits then converted to mp3

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In conclusion I have to say that it doesn’t matter if you dither before converting to MP3 or not. If you  it makes you feel better to do it then go ahead other wise don’t worry about it and go make some music.

For further reading on this, check out Steve Massey’s (Massey Plugins) blog post for April 2008 about dither.

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Tagged as: 16bit, 24bit, dither, MP3, POW-R