What is dithering, and how does it help?

[crispycutz]

Hey HR,
Just anoher term that sparked my inquistive nature. What does "dithering" mean? Is it essential in a mix, or is it selectivly useful like compression?
Thanks in advance, any feedback or links would be great.

 

[Teacher]

dither is essential whenever going from a higher bit depth to a lower bit depth. Dither is essentially low level noise which hides the artifacts of reducing bit depth and is also supposed to help preserve the sonic intergrity of the Track that the high bit depth had when going to a lower bit depth I.E going from 24 to 16 bits

hope that helps?

 

[pronoise]

Dithering is bringing your mixes bitrate and resolution down to the consumer use level (ie CD level 16/44.1) from superior bitrate and resolution. You do it not to improve your sound, but you need to do it, so that your material will be playable in CD players. Your goal is not to lose too much of the quality of your recording. Better dithering algorhtyms like pow-r 3 cause fewer artifacts.

www.pronoise.com

 

[LRosario]

but you need to do it, so that your material will be playable in CD players.
www.pronoise.com

Not totally accurate, dithering is just the addition of a low tone to maintain the sonic quality of a recording when converting bitrates. It cancels out low level noise produced by that conversion.

You would apply dithering to your master fader. One of the last items in the signal flow chain. For example, you would set your dithering options to 16-bit if you choose to go for the standard CD-audio

You could choose not to apply dithering and still have playback. It sorta falls under the mastering category, but common for both mixing and mastering engineers.

 

[Buck62]

How about a more simple explanation?

Let's say you have a picture of landscape and you need to fit it in a scrapbook-space that is smaller than the picture itself.

You can either:

A: Get out the scissors and trim off the edges to make it fit.

(OR)

B: Shrink down the picture so that it will fit in that space, keeping all of the scenery intact.


That's basically what dithering is... shrinking down the recorded sound and putting it in a smaller space without losing anything sonically.

If you don't have a CD-R that dithers, then you will truncate (or "lop-off") bits, which is just like cutting off the edges of your picture. Most of the stuff will still be there, but you'll be missing the true "full picture" of the original recording.

Truncating bits isn't always bad, but it's certainly not the ideal way to get the most out of your recordings. It takes away some of the clarity and detail when you truncate a 24-bit recording down to 16 bits.

Commercial CD recorders (..the kind you get at Best Buy and Circuit City) don't have the ability to dither... they will truncate your recordings. Pro-quality CD recorders like the Tascam CDR-700 (or the newer model CDR-750) automatically dither a 24-bit recording down to 16-bits and are a worthwhile investment if you are serious about recording music.

 

[crankz1]

Based around Izotope's Ozone plugin, but their Dithering Guide has some helpful information on the subject.

 

[masteringhouse]

dither is essential whenever going from a higher bit depth to a lower bit depth. Dither is essentially low level noise which hides the artifacts of reducing bit depth and is also supposed to help preserve the sonic intergrity of the Track that the high bit depth had when going to a lower bit depth I.E going from 24 to 16 bits

hope that helps?

Best and most concise explanation on this thread.

Additionally dither is used to help reduce quantization distortion which is essentially what teacher is saying. When reducing the bit depth you are converting from a larger scale to a smaller scale which involves calculations and rounding errors on the last bit. In order to kind of sweep these errors "under the rug" low level noise is used to randomize the last bit.