The goal of mastering is to polish your mix to a professional-sounding level that sounds great on all systems. Mastering involves a lot of technical processes, but we're going to focus on one aspect of it that comes right at the end: dithering.
You do not use dither before mastering. Rather, dithering takes place in the final stage of audio mastering. It’s used to improve the quality of the final product and can be applied in different ways depending on whether you’re working with vinyl or digital formats. In this article, we’ll explore dithering and how it can improve your mastering work, as well as some tips for avoiding potential issues when using dithering in your projects.
While many listeners won't consciously notice the effects of dithering, it can have a significant impact on the quality of your final master. Different playback devices and environments require different amounts of dithering. Making mistakes in this regard can result in a final master that does not sound as good as it should when listened to on other systems.
If you're not sure how to master a song, it's worth checking out a more general guide on mastering first. Adding dither comes right at the end of the process, so you'll need a firm grip on how to analyse your mix, how to EQ and how to use a music compressor as well as the concept of limiting first.
What Is Dithering In Audio?
Put simply, dithering in audio mastering is the process of adding noise to a digital audio signal in order to remove distortion. The distortion occurs when compressing audio files into smaller formats. Dithering stops this by adding a consistent noise to mask the distortion and volume changes.
Adding noise in itself is also actually adding distortion to the track. However, noise is a much more consistent, spread-out form of distortion than the alternative: quantisation distortion.
While quantisation distortion can completely ruin a track, a small amount of noise to even out distortion is unnoticeable to most human ears and also much preferable to the harsh distortion that can come from compressing audio.
Dithering can save you a lot here. But, it's not a magic wand you can wave at anything and hope it will remove artefacts. The importance of good quality audio recordings and file structure are much more important – dithering just helps to preserve the quality of audio when compressing it.
When To Use Dithering
You apply dither at the end of the mastering process when you’re exporting your final master track. You only need to apply to dither when you’re bouncing a file at a lower bit-depth than it was recorded e.g. from a 24-bit or 32-bit session down to 16-bits.
Some limiters apply dithering by default, so it's important to check your plugin chain before applying dithering in the exporting stage.
For instance, Waves L3 (the best mastering limiter) adds dithering to the limiter by default. This can cause issues when you have limiters set up in series to bear the load and create a more transparent master. Always check this before exporting (it matters)!
You'll also want to check in your DAW settings for dithering, because it's often left on.
Sometimes you don't want to dithering.
A prime example of this is in the recording stage – you want to keep the highest quality audio in your recordings as possible and are not exporting them in a smaller file format. Therefore, you do not want to apply dithering.
You only need to add dither if you’re mastering your music yourself. If you’re sending your track to a mastering engineer, and you can export 32-bit float files, don’t dither at all. The mastering engineer will take care of this for you.
What Does Dithering Do?
Dithering reduces quantisation distortion and improves the overall sound quality of your project when exporting files to a lower quality. I.E. 32-bit to 16-bit.
Quantisation distortion occurs when you're reducing the bit depth. Reducing the bit depth always prompts rounding errors, since computers are only able to store numbers in limited precision (0s and 1s). In the limited amount of error, there's bound to be some error – this is where dithering comes in.
Dithering uses noise shaping to improve this rounding error by adding random noise around the edges of each sample so that it doesn't appear as such a harsh transition point in your audio file.
If you don't apply dithering when exporting, you could find yourself listening to a more quantised, square-looking wave – which sounds about as weird as you’d expect.
As you can see, when you reduce the bit-depth of an audio signal (without dithering), it adds quantisation distortion, which looks exactly like you'd expect – squared-out waves. When you add dithering, it reduces this by adding noise.
The Different Types of Dithering & When To Use Them
Most DAWs (and plugins) will have a selection of dithering options to choose from. These change the noise style that is injected into your audio to even out quantisation distortion. Depending on the style of track, there are different styles of dithering.
For example, if you're exporting a quiet violin recording, it's going to need a different dithering setting to your loud, compressed EDM bass.
There are 5 common dithering options and they're as follows:
- Rectangular (even but with more quantization distortion)
- Triangular (set by default by Ableton and the safest mode to choose)
- POW-r 1 (special for quiet recordings, like acoustic guitars, ambient or vocals)
- POW-r 2 (for even audio files)
- POW-r 3 (great for loud mixes like EDM, hard rock, or any strongly limited genre)
Bouncing Audio – Why You Need To Bounce Tracks
If you're at the mastering stage, you should have already bounced your project once so that it exists as a stereo track in a lossless format such as a WAV or AIFF file. Once you're finished mastering your track, you'll need to bounce it again.
Before you export your final mix, make sure you're definitely happy with the tone, dynamics, loudness and compression in the master. The only way to tell if your mix is good is to listen to it carefully and critically.
Once you’re happy with your final mix, it’s time to bounce your music and finally use the dither effect. It’s crucial that you select all the right settings when exporting your master, you don’t want to mess up your track and undo all the good work you’ve just done. Below are 4 things to look out for:
- Resolution – Make sure that your final bounced file has enough resolution to avoid aliasing artefacts when it's processed further downstream. A good rule of thumb is to never export your track to a lower resolution than you’re using in your project. Try to keep it the same. Alternatively, if you have the option, you can export to 32-bit floating-point.
- Dither – This is the only time that you should have your dither setting turned on, when your tracks are leaving your DAW.
- Normalise – Opt to ‘not normalise’ your export files. You don’t need to ‘normalise’ the track if you’ve already been through your own mastering process.
- Channel Width – Select ‘interleaved’ when preparing to bounce.
- Offline Or Realtime Bounce – When exporting your track you’ll get the option to do an offline bounce or a real-time bounce. This comes down to personal preference. An offline bounce is when you export an entire project into one large file without any changes made to any of its tracks or settings. This can sometimes create problems if you need to access individual tracks later on because they are all combined into one large file with no separation between them. A real-time bounce is when you export individual tracks at once while still keeping them separate. A real-time bounce is much slower but it’s also the option that will give you more flexibility further down the line.
Bouncing Audio in Logic
In the below example, we look at bouncing in Logic which is generally considered an industry-standard DAW. However, the process is almost identical when looking at how to bounce tracks in Pro Tools or how to bounce in FL studio. Never think that you have to use one DAW or the other, it’s totally down to personal preference.
1. Select your export range
First, select the export range. You can do this by selecting the relevant regions, turning cycle mode on and typing Start and End values in the relevant spaces.
2. Click File > Bounce > Project
Then, in Logic, click on File > Bounce > Project. Alternatively, use the keyboard shortcut ⌘B on Mac.
3. Select your bounce settings
Choose whether you’d like to bounce in real-time or offline mode. Check that you’ve got your optimal settings in place for mastering. The main ones to look out for are Resolution, Normalise, Channel Width and of course, dither.
4. Click bounce and begin your export!
How To Identify Problems In A Mix
Now you've got your master track, you need to test it before letting it out into the world. One studio monitor test in a pro recording studio is not sufficient. You want to test your audio mix on a number of different playback systems.
It’s a very common mistake to rely too heavily on one particular playback device. For example, many people will mix their tracks in headphones and only reference their tracks on headphones. This is a bad idea because it's like having tunnel vision.
You make better decisions when you listen to your tracks on multiple devices and compare them to the same reference track. When doing this, you want to listen to the mix as a whole, then compare it to your reference track – what are the differences on each system between yours and your reference?
Keep checking on multiple systems, heading back to your DAW with notes and making changes until you get the mix translating correctly across all systems.
If you can get your mix sounding good on a sh*tty laptop speaker, it will sound good on most systems. However, if you don't have a good room that accurately represents all frequencies, you could be missing some problematic frequencies that can't be heard on that system.
In the same way, your mix might distort on a laptop speaker, or phone speaker – even your bass might be completely unhearable. The point is… you wouldn't know about these issues unless you listened on multiple systems.
There are also various plugins on the market that you can use to check your mix in a virtual studio, such as CLA NX (which we personally use all the time to quickly check masters). However, we'd always recommend trusting your ears in a treated room, above AI technology.
Hopefully, that's audio dithering explained. A good final way to check that your track is well and truly complete is to listen to your project pre-export alongside your bounced track. Can you hear the difference between the 16-bit and 24-bit files? If you can, that's normally an issue with the master, rather than caused by the change in bit depth, unless you've got supersonic hearing.
If it sounds really off, go back and check your dither settings, you'd be surprised at what a difference it can make.
With over 8 years of hands-on experience in the music industry, Harry has run successful raves, played alongside industry heavyweights such as Max Chapman, DJ EZ, DJ Zinc and more (pictured below), had music played on national radio, DJ'd on live radio, produced until he hated every song, mixed until his ears bled, created sample packs from scratch using just a Zoom H1n and some sound design skills… and pretty much anything related to music production – he's done it, tested it, tried it.