Good Dither is a very good dither that’s very easy to work with. Set it on “Optimal,” and it will optimize the dither and noise shaping for any combination of bit depth and sample rate.
Every time you reduce the audio bit depth you should dither to prevent distortion and quantization error. 24 bit → 16 bit, 32 bit → 24 bit — any time you reduce the word length.
To be honest, there are a lot of very bad dither algorithms in use: ones with nasty, overly aggressive noise shaping curves that can do more harm than good.
Good Dither’s noise shaping increases resolution while staying smooth & natural-sounding and avoiding extreme high-frequency peaks.
Dither adds noise to audio signals in order to prevent distortion that otherwise would occur. The noise shaping of the dither affects the frequency spectrum of that noise. Generally, the goal of a noise shaping algorithm is to move noise energy away from areas that the human ear is very sensitive to and to push it to places that we’re not as sensitive (very high or very low frequencies). The tradeoff is that aggressive noise shaping adds higher peaks in the dither signal, so the best dithers strike a good balance between noise reduction and avoiding excessive peaks.
The following chart shows the perceived noise reduction (more reduction = better) and the highest peaks relative to flat dither (lower = better).
|Dither Algorithm||Noise Reduction||Highest Peak|
|Goodhertz “High”||8 dB||24 dB||!|
|POW-R #3||7 dB||27 dB|
|FabFilter Pro-L “Weighted”||7 dB||27 dB|
|Goodhertz “Optimal”||6 dB||16 dB||!|
|FabFilter Pro-L “Optimized”||6 dB||19 dB|
|iZotope “High”||6 dB||21 dB|
|Apogee UV22HR||5 dB||27 dB|
|POW-R #2||5 dB||13 dB|
|Goodhertz “Low”||4.5 dB||10 dB||!|
|iZotope “Medium”||4 dB||12 dB|
|iZotope “Moderate”||3 dB||9 dB|
|POW-R #1||4.5 dB||26 dB|
|Flat TPDF Dither||0 dB||0 dB|
Correct! This dither algorithm was originally developed for use in Audiofile’s Triumph app, so the differences between the Goodhertz Dither in Triumph 2.5+ and Good Dither are minimal.
It is! If you’d like to license Good Dither for your app, contact us.
Drastic noise shaping can cause additional distortion, create MP3 encoding issues, or even become audible or damage tweeters in certain situations. ↩
The perceived noise reduction was obtained at threshold levels using multiple trained subjects listening in headphone (Sennheiser HD 600 and HD 280) and loudspeaker (ATC SCM50ASL and K&H O300) environments. ↩