dithering

I have a question about the dithering option under the audio menu. I have always left the defaults to triangular. What is this used for and what effect would it have if I changed the pattern? Is this just for exporting to 2 channel wave files? I read Scott's book which is a great read on how to use Sonar effectivly, but I didn't see any detailed explination of this dithering option.

If you get the chance, have a look at Bob Katz's book "Mastering Audio, the art and the science". He does an excellent job of explaining what it's all about without getting too technical. Well worth a read.

According to the Sonar help file...

Dithering--whenever an audio signal is converted from a higher-bit resolution to a lower resolution, it is necessary to apply dither to avoid introducing undesirable quantization noise or harmonic distortion into the signal. The purpose of dither is to reduce the resulting distortion by adding low-level random noise or "dither" to the audio signal. Different mathematical calculations are used to generate dither, each method has advantages and disadvantages depending on the particular operation. SONAR features the Pow-r dithering process, short for Psycho-acoustically Optimized Wordlength Reduction, which can produce lower-bit files that sound indistinguishable from higher-bit source files. When this option is turned on, SONAR uses dithering when you export a higher-bit file at a lower resolution, or lower the bit depth of a project's audio files by using the Tools-Change Audio Format command, or when you "render" audio (bounce, freeze, or apply effects).

Triangular dithering is less cpu intensive than Pow-r dithering because it offers no noise shaping. It is considered superior to Rectangular dithering because it does not suffer from modulation noise effects. It is preferable to noise shaped dithering(pow-r) when successive dithering occurs such as bouncing and freezing. Its disadvantages over the pow-r dithering is higher perceived loudness.

I think triangular is the default because it is a good compromise between quality and processing time. I use it for test mixes etc. but change to the Pow-r algorithms when I'm exporting a final cd master.

Simple two step guide to dithering:

- If the exported file will have any processing whatsoever, if you want to be on the safe side or if you have any doubts, use triangular (TPDF) dither.
- If you are exporting the final 16 bit master and you are sure there will be no more processing to the exported file, you can use one of the noise shaped dither like POW-R. Let your ears be the judge and use the one that sounds best for the material.

UnderTow