“But how can those old DACs possibly perform better than the best of today? They’re only 20/48. We have 32/768.”
Going from 16/44 to 20/44 actually makes more difference than anything else, when it comes to digital. Why? Although the Nyquist theorem says you can perfectly reconstruct a waveform from digital with 2X the sample rate, it assumes an infinite-bit ADC with no quantization error. The more levels, the less the quantization error. 16 bit = 65536 levels, 20 bit = 1048576 levels. 24 bits is 16 million+ levels, but nobody has ever achieved 24 bit linearity, period. The best DACs are about 19.5-20 bits, even after 20 years of “progress.” (Hence, “the lost decades.”) Higher sample rates are nice for analog filtering, but limit the amount of horsepower a digital filter can bring to bear…and it takes up more storage space. So that’s a tradeoff. And “32 bit?” LOLOLROFLCOPTER. There will never be any 32 bit music. Because physics.