In Reply to: RE: To Dither or Not to Dither? J. River/PonoMusic World posted by Ugly on April 20, 2016 at 20:20:01:
These ADCs output 24 bits as a result of signal processing. The DSP creates low order bits, and generally quality of DSP will suffer if there isn't at least 48 bits of resolution in the signal processing. In addition, most recordings go through additional DSP in post production. The same situation happens during playback if a digital volume control is used in playback, whether done in the computer or in the DAC.
If dither is not used when bit depth is reduced (e.g. 48 down to 24) the result is signal dependent distortion. This is true even if the original analog signal is noisy. For example, if the ADC is only "good" to 22 bits, it might have noise at the 22 bit level added into the output. Or, there might even be distortion generated by the analog equipment when handling high level signals resulting in even greater errors. However, none of these errors will necessarily hide the errors involved when dither is omitted.
If you look at signal numbers that are applied to manufacturers' spec sheets and not how the mechanisms actually work you will not get a complete picture. The limitation in one dimension (noise or analog distortion) does not justify a limitation in another dimension. Each type of distortion can and will be perceived separately by critical listeners. In the case of 24 bit dither, most people would consider the benefit small and might not be willing to pay a large amount to eliminate what is a low level distortion. However, the cost of doing things correctly is essentially zero, being just a few instructions added to software.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
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Follow Ups
- RE: To Dither or Not to Dither? J. River/PonoMusic World - Tony Lauck 04/21/1608:42:09 04/21/16 (5)
- After 15 edits and deletes, maybe this is finally close to what I mean. - Ugly 11:56:41 04/23/16 (4)
- RE: After 15 edits and deletes, maybe this is finally close to what I mean. - Tony Lauck 14:44:37 04/23/16 (3)
- Crookwood says 20-30dB into the noise is possible. - Ugly 15:09:29 04/25/16 (2)
- RE: Crookwood says 20-30dB into the noise is possible. - Tony Lauck 12:10:22 04/26/16 (1)
- RE: Crookwood says 20-30dB into the noise is possible. - Ugly 21:09:25 04/26/16 (0)