As these posts about the physical nature of the ear have shown, the question whether an information system is fundamentally analog or digital throws up some surprising and counter-intuitive answers.
If you drill down far enough into the physical nature of an information system, you’ll always reach a point at which things are both quantized (lumpy) and linear (continuous). This is because, according to quantum mechanics, all matter exhibits both wave and particle behaviour.
But doesn’t common sense tell us that the behaviour of a vinyl LP is linear, because the material of the grooves has a smooth, continuous shape? Well yes, but as usual common sense is wrong. The lumpy nature of the polymers that make up vinyl combined with the elliptical form of a stylus means that there’s only a certain number of possible interactions between the stylus and the groove surface. And if you zoom in far enough, those interactions can be adequately expressed in quantized (i.e. digital) form.
Now the degree of resolution you need to express vinyl in quantized form isn’t actually that great. In fact it’s rather less than the available resolution of the red book CD specification. In other words, CD is actually more analog than vinyl.
There’s an easy way to show that digital is able to represent vinyl with complete accuracy. If you record the output of your phono stage on a good enough digital sound card and then play the resulting wav file, then assuming your electronics are transparent it’ll sound identical to the original phono output.
And as Dave will confirm, the better your vinyl replay system, i.e. the greater its resolution, the more like digital audio it’ll sound.
The reason vinyl sounds “smoother” than digital is that it adds noise and distortion that we find pleasing. By contrast, digital lacks this distortion and can sound unpleasantly “dry”. As T. S. Eliot put it in the Four Quartets, “humankind cannot bear very much reality”.
If you think this is nonsense and that no discriminating audiophile could believe such stuff, do have a read of Jim Lesurf’s excellent Information and Measurement, especially chapter 12 (“Analog or digital?”).
:read:
Matt