Dither - My Ears can't hear it

[mattkw80]

I've thrown Dither plug-ins on many a Master Bus, because a book told I me I should.

But, my ears don't hear a difference.

Just to make sure I'm doing it right.....

1. I throw a Dither plug-in on the master bus.

2. Select "16-bit"

3. Leave all the "Dither Type 1, Type 2, etc." alone

4. RENDER my track



I really don't hear what this does, during - or after. With it, or without.

What am I listening for ?

[SouthSIDE Glen]

First off, I'd recommend playing around with the dither settings instead of leaving them alone. Each one represents a different type of dithering algorithm, each with it's own effect depending upon content. Sometimes you might like one over the other, or one may simply sound more apparent than another on any given source.

As far as what to listen for, don't expect any earthshaking differences. Try different dithers and during playback of each just close your eyes and lean back in your chair and let the mixes hit you as they hit you. Which one just feels better for some reason you can't quite put your finger on? Pick that one.

G.

[mattkw80]

I'll give it another go.... but I really hear no difference.

Will the EQ change, or the dynamics ?

[rayc]

I used the built in ditherer in Cakewalk pro audio 9.3 last week, (to change down from 24 to 16) and found, with a fairly hot mix, that there were quite a few bits of click/pop sort of artifacts. I assume the algorithm doesn't like hot mixes or that there was conflict with a plug.
I've yet to try a plug in ditherer. Are there any recommendations?

[pezking]

I do not know of a single DAW that does not do the dithering for you.

Apart from specialized applications, I can't really see a need for you to do it yourself.

You shouldn't notice the effects of dither until you have a very low level signal - one that crosses only a couple of quantizing levels. Even then it'll just sound like white noise.

[masteringhouse]

The differences in types of dither are usually very subtle. You can hear the differences mostly in the higher frequencies, particularly with different types of noise shaped dithering. In general the difference between dithering and not is that truncation lends itself to a granier, less "organic" sound than audio that is dithered properly.

[mattkw80]

Originally Posted by pezking

I do not know of a single DAW that does not do the dithering for you.

Apart from specialized applications, I can't really see a need for you to do it yourself.

You shouldn't notice the effects of dither until you have a very low level signal - one that crosses only a couple of quantizing levels. Even then it'll just sound like white noise.

Pezking -

So.... when I 'render' there is a certain amount of Dithering going on anyway ?

[masteringhouse]

Originally Posted by mattkw80

Pezking -

So.... when I 'render' there is a certain amount of Dithering going on anyway ?

If you're going from 24 bit to 16 bit I wouldn't assume it. Pro Tools systems for example will not. And since you want the option to choose the type of dither I wouldn't expect this to happen automagically nor would I want it to. Or at the least have an option to change it after the program defaulted to what it though was "best".

[SouthSIDE Glen]

Originally Posted by mattkw80

I'll give it another go.... but I really hear no difference.

Will the EQ change, or the dynamics ?

When it does matter, it will, in most cases, "feel" slightly different. Sometimes if you look too hard for it, you'll miss it. It's kind of like one of those 3D images where if you look at it in detail you see nothing, but if you just relax and let it hit you, it pops out.

There is a very good chance you won't hear a difference. It could be becase of the content itself that it just doesn't matter, it could be that your ears just are not there yet, it could be because your dithering algorithms just are not suited well for your content, etc. If you don't, I wouldn't worry about it.

G.

[NL5]

I can tell right away if my tracks are dithered or not. I'll put up some files later today with different dithering, and no dithering and see if anyone can tell which is which.

[mattkw80]

Originally Posted by NL5

I can tell right away if my tracks are dithered or not. I'll put up some files later today with different dithering, and no dithering and see if anyone can tell which is which.

Excellent NL5 - that could help.


Until I develop my ears more - how evil would it be to skip dithering all together ?

[NYMorningstar]

Originally Posted by mattkw80

Excellent NL5 - that could help.


Until I develop my ears more - how evil would it be to skip dithering all together ?

Well dither me timbres. Not dithering would be like waxing your car without buffing it.

[Ethan Winer]

Originally Posted by mattkw80

I've thrown Dither plug-ins on many a Master Bus ... my ears don't hear a difference.

Nor should you hear a difference. The importance of dither is one of the Big Lies among many lies in audio. There are two different recent threads about this - one at Gearslutz in the Mastering section, and another at Lynn Fuston's 3dB forum (main section). In both cases I proved - to my satisfaction! - that dither is inaudible in all cases, no matter what source material you have. And this makes perfect sense once you think about it.

The effect of dither is down at the noise floor of 16 bit material, meaning it's 90+ dB below the music and also masked by the music. Most recordings have a noise floor at least 20 dB higher than that due to room tone, guitar amp hiss, and so forth, combined from all the tracks in the mix.

I summarize the main issues in this article:

www.ethanwiner.com/dither.html

You can download a file where I turned dither on and off several times during the course of a mix, including right in the middle of a soft clean guitar part. Anyone who thinks they can hear dither is welcome to listen to that file and tell me where the dither is and where it's not. I have $100 that says you're wrong.

--Ethan

[masteringhouse]

From BK:

http://www.digido.com/bob-katz/dither-2.html

[Ethan Winer]

Originally Posted by masteringhouse

From BK:

http://www.digido.com/bob-katz/dither-2.html

Yes, the science behind what dither does is well known, and its effect can be measured. But it's not audible. And nobody, not even BK, could pick it out in a blind test. This is the real point. Hence my $100 offer to anyone who can state which parts of my test file are dithered and which are not.

--Ethan

[Robert D]

Originally Posted by Ethan Winer

Nor should you hear a difference. The importance of dither is one of the Big Lies among many lies in audio. Anyone who thinks they can hear dither is welcome to listen to that file and tell me where the dither is and where it's not. I have $100 that says you're wrong.

--Ethan

Ethan....Gasp...you can't see the kings new clothes? BTW, isn't that even odds on a coin toss, assuming there's no audible difference?

The way to listen to dither is to take the very tail end of a fade, down where you can't even hear it any more at normal listening level, and copy that part. Paste it into a new project, VIP, whatever..... and then crank the volume way, way up. I don't recommend just looping over the tail in the whole file just in case something goes wrong and you end up shredding your cones.

[pezking]

It all depends on what you are listening to. If you listen to something with a long reverb decay (at the point where the signal is +/- 1 LSB) you can clearly hear quantization distortion in the absence of dither - the worst example would be a sinusoid because it'd become square like. With the dither you don't hear it anymore - it just sounds random, like noise, however this noise is amplitude modulated about the wanted signal (music, whatever) and so you can still hear the programme material but slightly noisy.

However, given the correct programme material the effects of dither, and possibly dither itself are definitely audible.

Yes, the science behind what dither does is well known, and its effect can be measured. But it's not audible.

If its effects are inaudible, then what's the point in doing it?

[masteringhouse]

I won't speak for Bob (though from various articles and reviews he seems to be able to tell the difference between even various type of POW-R) this being one example:

http://www.proaudioreview.com/pages/s.0029/t.3293.html

Here is another site where various types of dither were compared:

http://www.24-96.net/dither/results.htm

I dunno Ethan, seems that some can hear at least a difference ...

Originally Posted by Robert D

The way to listen to dither is to take the very tail end of a fade, down where you can't even hear it any more at normal listening level, and copy that part. Paste it into a new project, VIP, whatever..... and then crank the volume way, way up.

Yeah but who would ever do that to a song? If that's what it takes to hear the dithering algorithm, then who really cares?

I won't say that no one can hear it, but I will say that a lot of people can hear anything if they listen for it...

[Ethan Winer]

Originally Posted by Robert D

then crank the volume way, way up.

Exactly. The only time dither can be detected is if you turn up the volume unnaturally during a fadeout, or a reverb tail that's mostly decayed, such that playing the rest of the track will blow out your speakers and your ears. To my way of thinking this is not "audible" because you can hear it only in a contrived test.

Originally Posted by pezking

If you listen to something with a long reverb decay (at the point where the signal is +/- 1 LSB) you can clearly hear quantization distortion in the absence of dither

Not at normal listening levels! And that's my whole point.

If its effects are inaudible, then what's the point in doing it?

This too is my point. It's not worth doing! I don't argue too strongly against the use of dither because it costs nothing. Maybe an extra half second when rendering a 3 minute tune. As opposed to 24 bits and/or high sample rates that waste a lot of disk space and CPU for no gain.

Originally Posted by masteringhouse

I dunno Ethan, seems that some can hear at least a difference ...

No, they only believe they can hear a difference. As soon as you test them blind all of a sudden that have no idea if the music has been dithered or not. Hence my $100 wager. Hey, you think you can tell if music is dithered or not? Go for it. Try my test file. I'll even up it to $200 just for you - the offer is good through midnight tomorrow.

--Ethan

[pezking]

Ever listened to flute that doesn't have dither? It's horrific.

The whole point of dither is that it's nicer (and less annoying) to listen to noise (i.e. dither) rather than distortion (quantizing distortion).

Ethan your argument is flawed - you can't guarantee that someone doesn't want to listen to the end of that reverb tail - in classical music, you will frequently hear sounds that go right down into the +/- 1LSB area. I recorded on location before Christmas, a performance of O Magnum Mysterium. It damn near peaks in places, and in others is right down there. It'd sound horrific without dither.

Perhaps in a pop/rock track with no range of dynamics the effects of dither are masked, but listen to something with a wide range of dynamics and you'll understand why dither is necessary.

I've just made a small demo of dither using very low level sine waves. Anyone want me to share it?

[Ethan Winer]

Originally Posted by pezking

Ever listened to flute that doesn't have dither? It's horrific.

Surely you exaggerate. Tell you what - email me a 24-bit file of a flute playing at normal levels peaking within, say, 6 dB of full scale. I'll post truncated and dithered versions for folks here to audition and guess which is which. There's a link to email me on my home page www.ethanwiner.com.

Ethan your argument is flawed - you can't guarantee that someone doesn't want to listen to the end of that reverb tail - in classical music, you will frequently hear sounds that go right down into the +/- 1LSB area.

Okay, let's analyze that scenario. If a piece of classical music is very loud it might hit 100 dB SPL on peaks. Dither is 90 dB below that, so that's equal to a noise floor of 10 dB SPL. What concert hall or living room has a noise floor anywhere near that low?

I've just made a small demo of dither using very low level sine waves. Anyone want me to share it?

I'd much prefer a recording of a flute or some classical piece so we can assess it in context at normal listening levels.

--Ethan

[masteringhouse]

Ethan -

The test file is 16 bit, so I'm not sure what it proves since from your description part was truncated, part was dithered, then the edited pieces were combined and dithered again. You basically masked out the difference with a second dither. It's an invalid test.

Here is a simple test, listen to the same file and change the type of dither. Also try taking the same file and truncate, then render again with dither. Listen back on a CD or bring it back in as 24 bit. Do you hear a difference? Many do. If not, get a better monitoring system and try again. If you feel the need to argue further speak with Dan Lavry, Nika Aldrich, Daniel Weiss, and other top DSP engineers. I truly doubt that they dither for no good reason.

[SouthSIDE Glen]

Originally Posted by Ethan Winer

As soon as you test them blind all of a sudden that have no idea if the music has been dithered or not.

That's a unfair testing parameter right up there with "listen to this and tell me what samplaing rate it was sampled at."

It's not that dithering has an identifiable "sound" or color that can be isolated and identified, any more than 44.1K has an identifiable "sound". It's not possible to listen to a recorng out of context - or even within some conetxts - and say definitively whether it has been dithered or not. But that's not the point in either case.

The question is to whether dither *changes* the sound. While on paper it's easy to demonstrate that dither should never audibly change the sound, I can tell you that I have "sensed" a difference (for lack of a better term). Not every time, mind you; I find it to be very content-dependant. Could I always hear a difference? No. When I could hear a difference, could I guarantee which one was dithered and which one wasn't? Not always, but more than 50% of the time the one that had a more comfortable, almost a more "analog feel" to it was the one that had good dithering applied to it. I couldn't necessarily pin it down to a describable effect, just that it left me feeling better.

I personally don't find it a black and white issue (I know, I'm dithering myself! Oh, the irony! ) I say try it and A/B. Pick whichever one makes you feel better. If it's the dithered one fine. If not, equally fine. If you can't really hear the difference, that's just fine too. But in my limited experience with the issue there are enough times where the effect, while very subtle, is real enough in enough to take seriously and not just dismiss as voodoo.

Just one man's anecdotal experience. YMMV.

G.

[pipelineaudio]

SouthSIDE Glen, can you have a look at this plugin?

http://www.stillwellaudio.com/?page_id=27

heres a direct download to the evaluation verion (uncrippled) http://downloads.stillwellaudio.com/...er-install.exe if you have a VST compatible host