Dithering in specific
- Thread starter ScottBrio
- Start date
Samplecraze
Zukan
Are you exporting at a different bit rate to the project file?
D
Dillin Quent
Guest
Dithering is a way for samples of a higher rate (24 bit or 32 float) to be converted in a lower bit, 16bit and keep the loss of info, ie 8 -16 bits of info to a minimum and sopund quality as high as possible.
That being said, you should wait to dither at the end of a mix down, not to specific tracks with in a mix.
Think about this, if you open a 16bit wave file into Wavelab, which is a 32 bit float station, and adjust any of the dynamics, gain, pan, pretty much anything, you now have a 32 bit wave file. You then render it to 16bit...ok time to dither.
this also applies to tracks in your sequencer. Dither after a mix down sicne if you do it before, most likey you are going to change something, and those changes are stored often times in those extra bits associated with you 16bit file ---in the other 8bits or 16bits depending on the program.
That being said, you should wait to dither at the end of a mix down, not to specific tracks with in a mix.
Think about this, if you open a 16bit wave file into Wavelab, which is a 32 bit float station, and adjust any of the dynamics, gain, pan, pretty much anything, you now have a 32 bit wave file. You then render it to 16bit...ok time to dither.
this also applies to tracks in your sequencer. Dither after a mix down sicne if you do it before, most likey you are going to change something, and those changes are stored often times in those extra bits associated with you 16bit file ---in the other 8bits or 16bits depending on the program.
Lord Thathidge
Spectral Disco Pimp
Dither is used when converting from a larger bit depth (say 24 bit) to a lower bit depth (say 16bit) to avoid distortion in the resultant converted file.
If we just convert from 24 to 16 bit without dithering, certain values are lost which can lead to distorted playback in the converted file.Dithering adds random noise to the sound which helps to prevent this distortion from occuring.
Why is noise any better or different to distortion, i hear you ask, well the noise can be filtered and / or shaped so that it is less audible than distorion would be.
If you have been working with a bit depth higher thatn 16 bit and wish to burn your final song / track to a cd to play in cd players then you will need to convert the bit depth of your file to 16 bit as you cannot burn audio cds above 16 bit. If you need to convert your file to 16 bit, that's when you'll need to consider dither although most bit depth converters have dither options built in.
If you have no intention at this stage of burning your song into audio cd format, i wouldn't worry about dither at the moment.
If we just convert from 24 to 16 bit without dithering, certain values are lost which can lead to distorted playback in the converted file.Dithering adds random noise to the sound which helps to prevent this distortion from occuring.
Why is noise any better or different to distortion, i hear you ask, well the noise can be filtered and / or shaped so that it is less audible than distorion would be.
If you have been working with a bit depth higher thatn 16 bit and wish to burn your final song / track to a cd to play in cd players then you will need to convert the bit depth of your file to 16 bit as you cannot burn audio cds above 16 bit. If you need to convert your file to 16 bit, that's when you'll need to consider dither although most bit depth converters have dither options built in.
If you have no intention at this stage of burning your song into audio cd format, i wouldn't worry about dither at the moment.
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dedo nervoso
New member
is that so? I mean, pretty much every daw processes the audio at a bit depth way higher than 24 bit, which will lead to quantization errors when exporting either to 16 or 24 bits. maybe dithering would be useless for 32 bit floating point formats but I honestly dont know this much.
I am curious however about when it should be used in the mixing process for optimum results, i.e. only on the final cut or used on more than one step.
I tend to think that any track should be dithered when bouncing, because adding dither to a quantization-distorted sample doesnt't sound like it would somehow rescue it.
I don't really use dithering at all until exporting the mix but if there's a better way I would like to know, rather than just take a guess and add a bunch of noise everywhere.
I am curious however about when it should be used in the mixing process for optimum results, i.e. only on the final cut or used on more than one step.
I tend to think that any track should be dithered when bouncing, because adding dither to a quantization-distorted sample doesnt't sound like it would somehow rescue it.
I don't really use dithering at all until exporting the mix but if there's a better way I would like to know, rather than just take a guess and add a bunch of noise everywhere.
audiotecnicality
New member
I'm going to assume you're in a 24-bit mixing environment. If you are mastering your own work, you should add dither as your *very last* plugin in your chain before outputting to file or DAT.dedo nervoso said:
If you are having someone else master your work, you should *not* add any dither anywhere in the project. You're only going to be adding unnecessary noise. (The exception is that if you want to test your mixes on an audio CD, you should add dither at the end of the main output chain).
Dither applies whenever a bitdepth change happens. 32-bit plugins dither their outputs to the project's bitdepth.
dedo nervoso
New member
thank you so much, man. your post just put it all together for me. nice!
I'm glad someone brought up this topic! I was just saying to myself the other day I should really figure out what dithering is! so here's another question. I'm I'm working in ProTools and my session is 24bit 48Khz, obviously I have to bounce it to 16bit 44100 to burn it to a CD. If I use a plug in like the L1 Ultimax or the L2, they appear to have a dither built in. Should I click it to 16bits or should I just let Protools convert to 16 bit when it bounces? What is the advantage of using a dither as the last plug in on the master fader before bouncing?
dedo nervoso
New member
You should add dither because there's a change in bit depth between the project and the output file. that's the rule covered in this thread.fertig said:
The advantage is that the dither noise will help eliminate some quantization distortion on the lower end of the dynamic range, given the source signal is deeper than the destination.
This wikipedia article on dithering is pretty helpful to grasp the concepts of quantization errors and how dither works. have a read at it. dither
audiotecnicality
New member
This is kind of a sidenote, but it's best to use multiples of your destination sample rate. For example, CD is 44.1kHz, DVD is 48kHz. If you want to use a higher sample rate for production stages, use 88.2kHz or 96kHz, respectively.fertig said:
I say this because downsampling is a delicate thing. When trying to downconvert 48kHz or 96kHz to 44.1, the algorithm has to estimate and throw away data irregularly. You get differing results based on the quality of your convertor because it's not an even division. 48/44.1 = 1.088435374... The quality of this kind of conversion depends on how many digits of this fraction the algorithm pays attention to - the more the better, but no algorithm will ever perfectly divide this, resulting in quantization error (as you'll read on that Wikipedia article posted by our friend above).
Whereas, with a perfect multiple (88.2/44.1 = 2.000000...), your downconvertor will (evenly) throw away every other sample, or average 2 adjacent samples - this is easier to process (since it calls for a far simpler algorithm), and is *much* cleaner in the end than the guesswork involved in 48->44.1, for example.
The setting on the L1 or L2 refers to the bitlevel of dither you want applied. Protools will not select this for you; it knows (based on your bounce-to-disk settings) what bitdepth to convert to, but Protools itself does not handle dither. It only takes a 24bit output (which you want the L2 to have dithered already!) and converts to 16bit.fertig said:
So let me rephrase for clarity. The *output* of whatever plugin adds your dither will actually be a 24bit stream, but will have the noise floor raised by dither to a 16bit level. Then Protools handles the actual conversion from 24bit to 16bit, your audio already having been prepped for conversion. Make sense?
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Yes, thanks, this is very enlightening. I found the wikipedia article still confusing, but there was a link on there to an article that explained it in a way I now understand it much better. If I can't go 96k because of hard drive space limits, is it worth doing my session 24 bit, 48khz if I eventually have to reduce it to 16 bit, 44100 or should I just work in 16 bit, 44100 the whole time? Thanks again for posting on this topic!
audiotecnicality
New member
My point was that if you're mixing for CD, which is 44.1kHz, it is probably *not* worth it to record in 48kHz. The extra samples aren't worth it because of the trashy down-conversion.fertig said:
If your target medium is CD, I recommend either 44.1kHz or 88.2kHz; don't bother with 48kHz or 96kHz unless your target is DVD. 24bit is a given. Keep your bit depth and sample rate as high as possible as long as possible. Send your mixes to a mastering engineer at 88.2kHz/24bit if you can. If the doubled samples are dragging your hardware capabilities, 44.1kHz/24bit will certainly suffice. It's not the best, but it'll work.
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