solderdude
Grand Contributor
It's not just the smoother analog filter that it allows, it's a whole different conception of sampling. In other words, If a Delta sigma ADC with a 5 or so bit Delta representation was only sampling at 44.1K. It could never reproduce 22kHz.
The vast majority of commercial recordings in studios are made at 96kHz or 192kHz. Some even higher. DS or different ADC is immaterial though.
After the recording is completed it is down-sampled to various formats. A very common one being 44.1/16.
This is always done with a sharp digital filter cutting off everything above 20kHz or 21kHz or so.
Dither can be used to effectively increase dynamic range of 16 bit files.
Then there is a product that is sold.
It is this product that has to be reproduced. When one wants > 20kHz there is often a high-res option 96/24 or 192/24 or higher for people that think they need it.
Then there is MQA as well.
This is the only format where a 44.1/16 container also has >20kHz content after decoding at the cost of bit depth. Note that some recordings still can sound very good even with 10 bits, only having a bit more noise when playing really loud.
Upsampling is only beneficial when the hardware it is played on performs technically much better when higher bitrates are used (signal fidelity).
This can even be the case when a physical DAC designer decides to use a DS DAC chip and only uses one of the poorer (not adhering to the sampling theorem) reconstruction filters. In this case it is done on purpose for people that believe this is the way to go.
Weirdly enough upsampling improves technical performance but at the same time 'removes' exactly that aspect that DAC is actually sold for as one still will be listening to upsampled/sharp filtered 44.1 files with no content above 21kHz and including the dreaded 'pre- and post-ringing'.