Thoughts on the future of HiFi

[theaudiohobby]

This clarifications help, thanks.

Is dithering always used? Or is it used mainly for downsampling? Or maybe I should ask for a general definition of "quantisation noise".

Quantization noise, also known as Quantization error is a rounding error which represents the difference between the Analog Input and Quantized sample, As the quantized sample is alway bandlimited, i.e. bandwith is not infinite, there is always a quantisation error, consequently the size of the quantization error is very much dependent on the sample rate and wordlength. As the sampling rate and the wordlength increase, the quantization error decreases. It's called Quantization noise when the error is modelled as noise. The big issue with quantization noise is that it is not totally decorrelated from the signal and that's where dither comes in, dither is random noise that when added to the signal in a deterministic fashion, decorrelates the quantization error from the signal. This process improves the output of the digitization process. And yes in most modern ADCs, dither is employed, due to it's beneficial impact on the quality of the digitized signal. As an aside, tape noise is a form of natural dither, it's random nature effectively decorrelates quantization noise from the signal during the digitization process.

Sorry for the late response, I have been a bit busy over the last few days.