To Dither or Not to Dither?

[TheElement]

This has probably been discussed before. Is dithering necessary? I'm guessing its used more for making mp3's.

What do you guys do? Do you dither?

Thanks.

[cassmcentee]

Gavin, I know I spent a day 2 years ago searching for the same answer.
I do dither my MP3's out of WaveLab as part of the mastering process
but not on my MP3's (general mix) out of Cubase
Why?
I can't remember, just that I read something 2 years ago...

...And now for a voice of wisdom to help us know why...

[TheElement]

Yeah Robert I saw a video recently about it and the guy exported a wav and imported it back into a blan session where he added dithering and then exported an mp3. I tried that today. Don't know if it makes sense if you are uploading to soundcloud. I just either upload a 320 mp3 or a wav and then of course SC does something to the file. Don't know how Taxi works or the others.

[Len911]

The short answer is yes! The only exception being if you stay in the same bit resolution. Since most daws and signal processors use 32-bit floating, anything you do would change it to 32-bit floating. Because most players tend to be 16 bit if you don't dither you get a truncated signal going from 32 to 16 bit. Analog doesn't use bits, only digital, remember the one's and zero's of digital? They have to be rounded off to fit the word length, or bit length, also called quantization, or "quantization errors". The idea of dither is to make those errors and their harmonics not so much recognizeable by turning them to noise or noise into a less noticeable frequency range, or a noise below the noise floor.

The idea is to apply it as the last slot in the chain before it is converted to a lower bit. It's sort of like you wouldn't want to down sample a 192khz sample to 44.1 khz and then back up to 192khz. Not the same thing but it makes the point I wish to make,lol!!

Here's a couple of interesting articles on the subject:
http://en.wikipedia.org/wiki/Quantizati ... cessing%29

Scroll down to dither and noise shaping.
http://www.sonnoxplugins.com/pub/plugin ... Detail.htm

In practice, if I decided to use the Elysia Alpha Compressor as the final limiter, I still put the Sonnox Limiter after it and used it for dithering. Sometimes I think I used whatever Cubase had. And there's probably times I've forgotten,lol! The point is, is that the Sonnox always has a dither, even if you don't choose, and I'm not sure all limiter's like the Elysia have it.

[Len911]

"Quantization also forms the core of essentially all lossy compression algorithms."
So it's essentially built in for mp3's. It's part of the algorithm.

I just either upload a 320 mp3 or a wav and then of course SC does something to the file.

Try dithering into a 16 bit wav file first before rendering your mp3, and dithering your wav before uploading to SC.

I suppose if you wanted to get a little more in-depth on your mp3's. for ~$55 you could purchase the Sonnox
Codec Toolbox. But if 320 bits is no problem, the only other thing it might be useful for is monitoring if your output needs to be turned down prior to rendering.
http://www.sonnoxplugins.com/pub/plugin ... olbox.html

[Kolstad]

As I understand it, dither is a way to hide artifacts that comes from downsampling.
So, I apply dither when I downsample, fx if I record and mix in 48k/24bit (which I always do), and downsample to 44,1k/16bit (CD format) when I export the mix out from my daw.

I think dithering only works if you do it once in the conversion process, so you shouldn't dither a file that already have been dithered, that would add unwanted noise.

Izotope has a comprehensive free guide to dithering.. http://downloads.izotope.com/guides/izo ... -ozone.pdf
And a basic need to know video https://www.youtube.com/watch?v=vVNzylf9sGo

[cassmcentee]

Thank You gents for the info,
We need to remember (in mastering or final stages) to dither anytime we are dropping a wave down in bits!!!

[guitargurumike]

same here, I researched it long ago and forgot why, but I always dither using my L2 limiter at the final mastering stage, it has a "dithering" button thingy and you can change bits or whatever. That too technical?

[andygabrys]

same here, I researched it long ago and forgot why, but I always dither using my L2 limiter at the final mastering stage, it has a "dithering" button thingy and you can change bits or whatever. That too technical?

and as Len911 noted above....

basically yes. you do it one time at the end of mixing if you are creating a master that is 16 bit depth.

If you are not mastering, or if you are preparing hi-res stems that are 24 bit, there is no reason to dither. As the session format is going to be at best 24 bit.

if you have a DAW that allows 32 bit depth, check to see how its doing it - as there are very few AD convertors on the market right now that capture at 32 bit depth. You might just be making the session files 25% bigger (over 24 bit) for absolutely no gain. (no pun intended...get it.....gain...anyways).

and yes like was noted above - you dither once.

can most people hear it under normal circumstances?...............

but its what we do cause the golden eared people have figured it out.

[eeoo]

I don't do it cuz I don't understand it and I can't hear the difference.

eo