What’s “dithering”? And why is it used on CDs?
In: Technology
This picture shows what dithering is with images:
[https://upload.wikimedia.org/wikipedia/commons/1/18/Dithered_bgw.png](https://upload.wikimedia.org/wikipedia/commons/1/18/Dithered_bgw.png)
Basically if you want to smoothly transition from black to white but you don’t have a lot of shades of gray, you use patterns of dots instead.
The same is true for audio. CDs are a digital format, that means that they use whole numbers like 1, 2, 3 to represent the audio signal.
Sometimes, especially for very quiet music, there aren’t quite enough “levels of gray” to represent the audio signal quite right. So they use dithering to approximate it.
It turns out that if you don’t dither properly, it can add some audible noise / sound artifacts that you can hear. With good dithering the artifacts are smoothed out so they’re not perceptible.
The Wikipedia article is long but it has some examples of audio dithering you can listen to.
[https://en.wikipedia.org/wiki/Dither](https://en.wikipedia.org/wiki/Dither)
You might not be able to hear the difference unless you’re using high-quality headphones connected directly to a PC. If you’re using cheap speakers or bluetooth headphones then you won’t hear the difference because the difference is too small for those to reproduce.
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