Dither

[jpoloyannis]

Hi All,

 

This is probably not strictly a Logic question, and probably applies to all DAW's. I am curious as to how anyone knows (apart from I can hear the difference) an Audio file has had dither applied...is there an indicator in logic,. etc?

 

Cheers JP

[marcperi]

As far as I know dithering is a numerical elaboration to avoid digital “noises” when you make a de-resolution from for example 24bit to 16. If you want to think about it visually, is something similar (only visually) to the windows defragmentation. There are not metadata about the dithering, and I don’t think you will be able to recognize which dither algorithm has been applied.

[jpoloyannis]

Thanks Marco

[David Nahmani]

Indeed, dithering is basically adding low level noise to the digital audio file, and I don't believe there's a way to tell if a file was dithered or not.

[jpoloyannis]

Thanks David,

[David Nahmani]

You're welcome!

[Holger Lagerfeldt]

Hi All,

 

This is probably not strictly a Logic question, and probably applies to all DAW's. I am curious as to how anyone knows (apart from I can hear the difference) an Audio file has had dither applied...is there an indicator in logic,. etc?

 

Cheers JP

I don't think you can spot it (easily) in Logic Pro X, unless you have two files and compare them.

 

If you find a tail or very low level signal and boost it significantly, you might be able to recognize quantization noise in an undithered signal, without even having access to the original file.

 

First make some tests with truncation and dithering/noise-shaping, then boost and compare the signals. This will make it easy for you to spot how quantization noise and dither sound like.

 

With a spectral analyzer. such as Izotope Advanced RX. you can (depending on the file) identify dithering, including a good guess at what algorithm was used, especially if the file has some empty parts and auto-blanking wasn't activated.