Dithering Audio [How it Works. Explained]
Audio Basis - articles about audio
Dithering audio is a suppression method of non-linear audio distortions when bit depth is decreased. It is adding specially generated very weak noise to a digital signal. The dithering algorithm of AuI ConverteR 48x44 (alphaD) observes the signal behavior. It allows for minimizing noise influence on hearing and open minute details of a music.
We will not tell you about dithering mathematics. You can read it at another place. We'll just show what you get. Keep reading...
Case #1: without dithering
You have 24-bit or 32-bit (integer or float point) source. You need 16-bit source.
Pure modeled sine signal 24-bit or 32-bit (float point also)
Now we make 24-bit to 16-bit conversion without dithering. When 24-bit signal truncated to 16-bit one, rounding to thr nearest integer is doing.
Pure sine after 24-bit to 16-bit truncation. Appear non-linear distortions
We see in this picture non-linear distortions ("wood of blue sticks"). Middle level of peaks of the "sticks" is about -135 dB.
Levels of these distortions increase and decrease together with the useful signal. In ther words, the distortions correlate with the useful signal.
No signal = No these distortions
The "digital sounding" is consequence of these "sticks" and their correlation with useful signal. And it is not "not very pleasant".
Case #2: with dithering audio
Now we will see 24-bit to 16-bit conversion with Audiophile Inventory's dithering audio alphaD.
In settings of AuI ConverteR 48x44 we set minimal value (Light) of Dithering mask depth... slider
Dithering audio settings of AuI ConverteR 48x44 - Light value (recommended)
That is result of 24 to 16 bit conversion
Conversion 24 to 16 bit with AuI's dithering audio alphaD
Now we see 2 things:
1. Mid level of peaks of noise about -145 dB.
2. The noise does not depend on the behavior of the signal. Now we loss "digital sounding".
If necessary we can add dithering intensivity for mask non-linear distortions by moving of Dithering mask depth... slider to right.
Attention!!! Non-traditional case!
Let's look to generated without dithering source 16-bit sine.
Source 16-bit sine generated without dithering
"Wood of sticks" again :)
Below we will see how does slider Dithering mask depth... position to signal spectrum. How it mask the non-linear distortions.
We can mask source non-linear distortions with changing Dithering mask depth... slider position.
AuI ConverteR's alphaD dithering
Audio file converter AuI ConverteR provides own dithering technology alphaD. The method smooth "16-bit artefects" and keep low noise.
It supported in all version of the program.
In configurable Modula-R edition, dithering is provided by "Base (core)" module.
Conclusions
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Dithering allows getting more "transparent" sounding without "16-bit digital artefacts".
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However, the dithering increases average noise level due to the artefact's enetrgy is distributed over frequency band of signal.
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In common case recommended use Light position of slider Dithering mask depth... in Settings windows of AuI ConverteR 48x44.
- We can mask non-linear distortions of 16-bit sources with moving slider Dithering mask depth... to 3 or 4 position (from left).
Frequently Asked Questions
What is dithering used for?
The audio dithering is used to smooth non-linear distortions in 16-bit resolution.
See more...
Read about audio
- What is Jitter in Audio. Sound Quality Issues >
- 64-bit audio processing. Necessity or redundancy >
- What is Audio Converter >
- How to Choose the Best Audio Converter Software >
- What Is Ringing Audio >
- Bit-Depth Audio and Harmonic Distortions >
- Audio as Optics >
- What is optimization audio for DAC >
- Where is the Limit of Audio Quality? >
- Power Conditioner for Audio. It's real advantage? >
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December 2, 2022 updated | since March 3, 2014
