Hi there,,
every representation of analog is connected to the instance that the signal is at one or more points in the chain:
A magnetic field.
Examples: Microphones, tubes, transformers, tape heads, pickup-cartridges, loudspeakers.
When we listen to analog recordings, we could have the insight, that the better the recording, the more often the signal passed through as a field.
I you compare f.e. the Eagles records, you get a very good feeling for the decline of audio quality that has happened over the years.
The record Eagles from '72 sounds wonderful.
Desperado '73 very very good.
On the border '74 very good.
One of these nights '75, still good, but now it starts becoming flat.
Hotel California '76, well many think it sounds good, actually not far as good as the old ones.
The Long Run '79 has lost all of the original Eagles quality sound.
I have all those records and can clearly hear the decline in quality that I point down to the fact, that tube-equipment was replaced in favor of transistor equipment.
The effect is that many parts in the whole recording chain, where the signal originally passed as a magnetic field, now it just passes as electric current through silicon transistors.
Although as measurements suggest that devices operating on a field create distortion and transistors are much more accurate, we know that without those fields, we cannot enjoy music at all.
Look at todays desperate attempts to get that kind of magnetic field sound with digital means.
You can indeed say, that the resolution of a field is indeed infinite or at least: it cannot be captured with bits and sample-rates.
But this is not necessary, as the purpose of playback equipment is to reintroduce those subtle harmonic structures.
The problem of digital playback is just ONE:
Square Waves.
All that we try to capture are sinewaves, and all our converters put out are square waves.
As you all know, squares consist of odd harmonics alltogether, so the main job of digital reproduction is filtering out those high-order odd stuff.
You can imagine that the larger the squares, the more difficult it is to filter them into a round wave-form.
Now can you reduce the size of the squares by going from 16 to 20 or 24 bits ? Indeed not.
If you want to have smaller squares, you need to increase sampling rate.
Charles