Every sound you hear in real life that doesn't come out of a speaker is analog. Analog audio is, simply put, an analogous record of sound, and an LP's groove is a literal imprint of the music's soundwaves. Analog magnetic tape is just as analog, but the waveform is recorded to the orientations of the iron oxide particles bonded to the tape. Tape or LP, analog recordings store audio signals as a continuous wave in or on the media and therefore have theoretically infinite resolution.
Digital audio recording converts the original sound into a sequence of numbers; sampled to convert the analog signal to a digital representation. Sampling is the division of the signal into discrete intervals (CD's sample rate is 44.1 thousands of samples per second). CDs have a 16-bit resolution and DVD-Audio discs can be encoded with a maximum of 24-bit resolution. DVD-A's have greater bit depth results in finer gradations of sound compared with CDs and MP3s, and is subjectively on par with analog recordings. Analog-to-digital processing is performed by a converter in the recording studio; and must be converted from digital-to-analog to be listened to.
If I lost you with all that talk about sampling and conversions, let's just say the prime difference between analog and digital is that analog recordings are continuous in time, and digital is sampled at distinct intervals. What happens between samples? Not much. Analog is always "on," digital is either on or off. Analog recording's theoretically infinite resolution refers to its continuity, compared with digital's on/off sampled nature.
If digital audio sounds a lot more complicated than analog, that's because it is. But digital recording offers very significant advantages over analog recording; it has inherently lower noise, perfect duplication capabilities, and superior speed accuracy (lower wow and flutter).
Most of the digital audio advances since the early days in the 1970s come from today's superior A/D and D/A converters. Digital audio has never sounded better than it does now.
The same can be said about analog: the best LPs, played back on a good turntable sound more like real, live music played by human beings than digital recordings ever do. That's my subjective opinion. On a more objective basis I'd say digital eliminates, or lowers analog-type distortions (noise, speed variations, and so on), but it suffers from far from perfect analog-to-digital and digital-to-analog conversion processes. To many, but not all, audiophiles and recording engineers, the best digital still sounds sterile, cold, and lacks natural warmth.
At this point, I feel duty bound to concede digital wins on mass popularity; most new music is digitally recorded and listened to over digital devices. The reasons for digital's "victory" have little to do with sound quality; digital is cheaper (or free), and it's more convenient to use than analog.
But the LP's resurgence grows stronger every year. Here in New York City where retailers pay sky-high rents, I see more and more vinyl on display. They aren't stocking vinyl because it's groovy, they're devoting more and more shelf space to LPs because they sell.
Analog and digital audio formats are both imperfect; the best of both types still fall short in creating truly life-like sound. So for the time being we should enjoy analog and digital for what they do well.
As always I'd love to hear what you think, but please, if you haven't recently heard a Geoff Morrison's terrific article on digital audio in Home Entertainment magazine.don't bash analog. To learn more about digital audio, read
Coming soon: The aesthetic of digital audio, and why the perfect sound forever CD may not sound better than the imperfect LP.