Modern DACs and ADCs (sigma-delta) get around this entirely by oversampling/upsampling then low pass filtering in the digital domain with a minimal if any analo

Modern DACs and ADCs (sigma-delta) get around this entirely by oversampling/upsampling then low pass filtering in the digital domain with a minimal if any analog LPF. This avoids all the issues you describe and with noise shaping the added noise is inaudible (unless you want to claim you can hear -100dBFS which would be pretty amazing) >So they are mentioning alternative (b). The problem is that oversampling does not solve all problems. Oversampling implies that the filtering is done on the digital domain and there are several choices of filtering you could use, for example FIR (Finite Impulse Response), IIR (infinite impulse response), etc. And each one of these choices have side effects... Citation needed here, oversampling solves virtually all the problems + with modern DSP the FIR filters can be made extremely good. the induced noise of modern adc/dac's is seriously tiny, and swamped by the recording noise of your audio.