Dither

[Gizmo]

What application does dither play in master? Any tips on how to use it correctly?

[Rodney Gene]

http://theprojectstudiohandbook.com/directory.htm

http://www.pcrecording.com/dither.htm

[tINY]

Dither is used to spread out quanitzation errors. It takes "artifacts" and turns them into "noise". Usually dither is applied at the converters, not at mastering.



-tINY

[Darius van H]

interesting fact: Dither was discovered/invented by the Germans in WWII.....they noticed that their air-borne gunners were more accurate then land-based ones....eventually they realized that the vibrations of the plane were talking up the slack in the the gun mechanism, resulting in more accurate shooting.

I read it on the internet so it must be true!

[max cooper]

Good point, but maybe it was harder to become an air based gunner?

[cdog]

Dither is used to preserve the dynamic range of a 24 bit recording when its truncated down to 16 bits.

Its actually almost inaudible noise which pushes the lowest level audible content of the program material into the more audible region, making the recording seem to have greater than CD quality dynamic range.

I like POWr #3 for most program material.

Contrary to what Tiny said, dither is almost always applied during the mastering stage, although some A/D converters allow you to dither in real time while recording this is usually never done, as you want to preserve as much of the original signal as possible. Dither is only apllied once, almost always at the mastering stage on full program material.

But, I'm not a professionaly mastering engineer, more of a recording specialist.

[joeq]

Originally Posted by Darius van H

interesting fact: Dither was discovered/invented by the Germans in WWII.....they noticed that their air-borne gunners were more accurate then land-based ones....eventually they realized that the vibrations of the plane were talking up the slack in the the gun mechanism, resulting in more accurate shooting.

I read it on the internet so it must be true!

or maybe if you are a ground based gunner and you missed you just missed, but if you are an airborne gunner and you missed the fighters shot you down.

I heard a VERY similar story about WWII airplanes providing a metaphor for dither but in the version I heard, instead of a gun, it was a mechanical inertial guidance system, basically a clockworks thing that performed better in the air than on the ground due to the plane's vibration loosening up the gears. Also, it was British planes in the story I heard.

I also read it on the internet!

[tINY]

Originally Posted by cdog

Contrary to what Tiny said, dither is almost always applied during the mastering stage, although some A/D converters allow you to dither in real time while recording this is usually never done, as you want to preserve as much of the original signal as possible. Dither is only apllied once, almost always at the mastering stage on full program material.

Good to know. Last I looked at it was 10+ years ago when 16bit A/D needed an edge for critical recording.

I would have thought that shifting up the signal so that the highest peak was 0dB and truncating the 8 LSb's would give better results than adding pseudo-random noise at -96dB.


-tINY

[Gizmo]

Thanks. I encountered dither in the waves L2 ultramaximizer. It also has three noise shapping options. I think they have something to do with frequency roll offs of the noise. Does anyone know the proper application for them?

[tINY]

You got it, it describes the shape of the noise that is added to the signal.... unless things have changed in the last several years



-tINY