All About Dithering

moses

hardliner
That's a really good one. Very accurate (which is quite rare).

An important point about all this is that the topic has been horribly raped by marketing. Dithering is important to keep in mind when truncating an audio signal, but which one you use (i.e. which kind of shaping and other voodoo) is TOTALLY overrated.

The main reason for this is that nearly all real world signals already contain WAY MORE noise than a dither would add. This makes the dither obsolete.

The second reason is that we're talking about events happening at the very last end of human perception and several dBs below the typical noise of 99.9% of the analogue gear out there (which is roughly around -70dB SNR, but 16bit dithering has a level around -90dB ) - in this case, we're neither able to measure any kind of effect nor will most people on most playback systems hear the effects of dithering at all.

There's way too much esoteric hype around dithering IMO. Fact is, most listeners won't care at all. Don't waste too much time with it. Dithering gets really important in low precision applications (below 16 bit), but is nearly useless at higher precisions (again, because we're working with signal that already contains noise far above the least significant bit).





BTW, one of the best introduction I've heard is:
…one of the earliest [applications] of dither came in World War II. Airplane bombers used mechanical computers to perform navigation and bomb trajectory calculations. Curiously, these computers (boxes filled with hundreds of gears and cogs) performed more accurately when flying on board the aircraft, and less well on ground. Engineers realized that the vibration from the aircraft reduced the error from sticky moving parts. Instead of moving in short jerks, they moved more continuously. Small vibrating motors were built into the computers, and their vibration was called dither from the Middle English verb "didderen," meaning "to tremble." Today, when you tap a mechanical meter to increase its accuracy, you are applying dither, and modern dictionaries define dither as a highly nervous, confused, or agitated state. In minute quantities, dither successfully makes a digitization system a little more analog in the good sense of the word.
—Ken Pohlmann, Principles of Digital Audio[1]
 
Last edited:

WeissSound

Engineer
Moses, I totally agree. The difference between dithering and straight truncating is almost imperceptible on all but the best sound systems. What type of dither algorithm? Who cares?
 
Last edited:

DCC Productions

New member
i notice a pretty big difference in how my kicks sound coming out of reason if I check the dither box.....i just mix it down and leave it unchecked now
 

astroidmist

New member
I tried to see how dither sounds so i ran some tests in CoolEdit 2000 using different types of dither on a faded-out sinewave. Most of the time it seemed like the noise-shaped dither made it sound worse and with a kind of buzzing that i think could be audible maybe sometimes. So I stopped believing in noise shaping around then. Then later on I realised that I had been forgetting to dither some of my 24 and 32-bit bit tunes that CDburnerXP was burning to disc. I don't think CDburnerXP does any auto dithering so the tunes were just being truncated. Of course, I couldn't hear any difference. The tunes sound just fine, even the ones with precise fade-out tails. So I stopped believing in dither back then. And fundamentally, I don't like the idea of adding noise to my tunes which are supposed to sound clean... even if I can't hear the noise, I just don't like the idea. Like Moses said, there's already a lot of low-level noise in the source audio by the time it gets into multitracks and is processed.
 

apineda

New member
Nice nice. Dithering has always been a mystery to me, and a burden in not knowing anything of it. My fault.
 

sleepy

Moderator
There came a point when I stopped dithering. There were times when there was some difference but not enough for me to see it as a crucial step that I had to use.
 

DJ Spinn

Spinn
I just finished pre-mastering a song that I most recently produced. I pre-master it without the vocals, so my artist can get an idea of what the finished product is going to sound like once her vocals are recorded and mixed onto the track, and quite honestly, after I dithered that file, the actual 16-bit file sounded a whole lot better that just simple truncation. Then from there, I MP3'd the file and emailed it to her for rehearsal. Even in a situation like that, I will always prefer to dither as opposed to truncating. The sound is not being degraded (so-to-speak) like it does when going from 96Khz to 44.1Khz.
 

Bryst

New member
OK, so maybe a silly question, but I've always wondered this. Why don't they just make Audio CD's 24 bit?? I record at 24 bit 48k on my system, and when I test the mix in my car, I'll export at 24 bit 48k and burn a CD.

Does the process of burning the CD automatically truncate it down to 16bit 44.1??? I have no idea, honestly...

If not, and you can make 24bit 48k CD's, why don't they??
 

DJ Spinn

Spinn
Yes it does automatically truncate it and converts the sample rate. If you broke down that CD by bits & numbers you'd be able to see for yourself it was truncated and converted. I did the same exact thing myself a few years ago and asked myself the same question. That's why I always prepare the song before burning. This way what get's burned is exactly what I created, and bit's & frequencies won't be lost. Every once in a while I will record at 48kHz too, but before that CD get's burned, as I dither, I will convert the sample rate to 44.1kHz.
 

TEKONE BEATS

New member
thank you for posting this.... good informative read !!!! i will not be dithering anymore when drums and bass are present.. check out my beats!! link in the sig.. how many posts before the widget appears?
 
Top