January 7, 2015
Here are a few important tips for achieving the best results with dithering:
Check our guides
Ozone's Mastering and Dithering guides contain useful information on the science and application of dithering.
Work in a high-fidelity format
When mixing a project, applying effects, and mastering, it's always advantageous to work at the highest sample rates and bit-depths possible on your system - this allows for greater resolution in all mixing and effects DSP, and results in fewer roundoff errors and artifacts.
Suppose, for example, that you wished to create a 44 kHz / 16-bit CD mix from various 44 kHz / 16-bit and 48 kHz / 24-bit samples. Rather than converting your 24-bit samples down to 16-bits, and mixing the whole project at CD quality, you would ideally convert your 16-bit samples up to 48 kHz / 24-bit (or higher), and mix everything together at this high-fidelity format.
Choose an appropriate dithering signal
Aside from avoiding the pitfall of converting down too early, you can also improve your mix by choosing an appropriate dithering signal. Returning to the above example, you might end up with a final mix at 24-bit or even 32-bit depth. Now, when converting this final 32 or 24-bit master to CD format, you might prefer not to use your hostapp's internal dithering (if it has any), but to use Ozone's MBIT+ dithering instead.
To use Ozone for dithering, you must first manually disable any internal dithering applied by the hostapp. This prevents the two dithering signals from adding together and conflicting.
Then, because we don't want to process our file after dithering (we'll go over this next), we need to downsample to 44.1 kHz *before* we handle our dithering and bit-depth. So convert your mix down to 44.1 kHz, but leave the bit-depth at 32 or 24-bit.
Finally, load this final 44.1 kHz / 32 or 24-bit master in your host, load Ozone as an effect, and select the desired dithering settings in Ozone's "Loudness Maximizer" module. Then perform your final bounce and output to a 16-bit file.
For dithering to work, it must be the absolute last edit performed on an audio file, except for the final conversion to 16-bit depth. This means that any effect applied after dithering, even a slight gain adjustment, or a sample-rate conversion, can undermine the positive effects of your dithering.
For this reason, it's important to make sure that no changes are made to your mix between dithering and the conversion to 16-bit CD format, and that nothing changes this file afterwards - it needs to be written to CD exactly as it is, with no added gain adjustments or fades. Some hosts may reserve a special slot for dithering plug-ins to reside in, and are designed so that no fades, mixes, or gain changes can occur after the dithering plug-in is applied.
Don't Process After Dithering
Taking all of these tips into consideration, here's an example work order to take you through the last stages of mastering and dithering:
Using your hostapp, produce a high-quality mixdown of your song in a high-fidelity format, such as 48 kHz / 24-bit or 96 kHz / 24-bit.
Use Ozone and any other plug-ins to perform mastering and add mastering effects, and mixdown again to your high-fidelity format.
Be sure any dithering features in your host app are disabled. Now use your host to convert your mix down to 44.1 kHz, but leave your bit depth alone for now - i.e. it should remain at 32 or 24-bit.
Make sure no other plug-ins are being used in your host, and that all gain sliders are set at neutral - we don't want any changes to be applied after dithering.
Now open your 44.1 kHz mix in your host, and load Ozone as an effect. If your host offers a special plug-in slot for dithering, use this.
Enable Ozone's Loudness Maximizer module, and choose the dithering settings for your mix.
Apply Ozone to your mix, and immediately output the final product as a 44.1 kHz, 16-bit audio file.