I’ve had a fair amount of experience with recording media from an actual WWII vintage wire recorder to a rim drive analog tape recorder (my first tape machine) through the high definition PCM digital equipment that I use today. Each of these formats has a rather stringent set of specifications or attributes associated with it. One of the attributes is resolution.
For example, vinyl LPs and analog tape (and I suppose the vintage wire recorder) have “infinite” resolution according to supporters of analog formats because they store musical information as a continuously variable model of the original acoustic waveforms.
Digital recordings are by their very nature discrete representations of a waveform sliced into a multitude of samples. The number of samples varies greatly and gets tied in with the frequency response as defined by the Nyquist Theorem for PCM. The DSD crowd likes to say that a sample rate of 2.8224 kHz (or higher multiples of that number) actually approximates the “infinite” attributes of analog recording, but in reality anything that’s digital is discrete and can never be analog. All you have to do is look more closely at a very high sample rate.
I think it’s pretty obvious that “infinite” doesn’t fully capture the sense of fidelity that a format is capable of storing and reproducing. Is there something inherent in the analog storage and playback of music that guarantees superior quality? Of course not! So why do so many supporters of analog formats retreat to the simple-minded argument that if something is analog, it must be better than all other formats? As always, this has nothing to do with one’s personal sonic preferences! Everyone has the freedom to like what he or she likes.
Wouldn’t it make more sense to evaluate the entire process from recording through playback against various metrics? Even analog advocates acknowledge that there’s more to fidelity than just the “infinite” nature of the signal model being stored. Designers of analog recording system have had to contend with mechanical and electrical issues since the first machines were built many decades ago.
The accuracy of the mechanical systems can never be completely perfected so there’s bound to be shortcomings in the speed of the transport (wow & flutter), the intimacy of the tape to head contact due to dirt, grease, oxide shedding or edge damage or the scraping of a stylus or magnetic head across the recording media (a vinyl LP or analog tape).
Electrical signals are also subject to imperfections and distortion along the way. There’s harmonic distortion, self-erasure degradation, crosstalk, print through and clipping just to name a few. Even the finest circuits and components can’t completely remove these problems with an “infinite” resolution format.
And yes, the world of digital has it’s own set of issues…but they are different issues. We’ll talk about that in more detail soon.
But the bottom line is that the output of a digital to analog converter (especially the good ones that are used by audiophiles) is an analog signal has just as much “infinite” resolution as the output from a turntable spinning a vinyl LP! The process and storage of a selection of music in PCM or DSD digital isn’t reproduced as a discrete series of voltage steps that drive your amplifier and ultimately your speakers. The output signal is a completely smooth rendering (or should I say re-rendering) of the original analog signal that was converted to digital by the analog to digital converter at the other end of the process.
When someone says that analog formats have “infinite” resolution vs. the discrete “stepped” resolution of digital, it doesn’t mean anything. The output of either format is a smooth, periodically changing electrical signal.