Authentic Audio—Part 1

I have been a music-listening freak ever since, as an 8-year-old kid, I discovered what it was like to listen to 78 RPM records on my aunt's post-World War II Victrola. (I realize that many younger people today may not fathom a few terms in that sentence, so here's an abbreviated glossary. 78 RPM: the turntable rotational speed of primeval record players. Victrola: a generic term for some of those ancient machines. Post-World War II: the late 1940s and early 50s. Okay; we're on same page now?)

I discovered at this tender age the magic of listening to recorded music: I could play it over and over again—until I either knew the song by heart, or the record became too worn-out for me to tolerate the noise of its scratches and pops and clicks. Today's younger generation knows little about how analog records deteriorate with age or careless handling, as they can play a CD or other digital audio file endlessly and never wear it out.

So the experience of listening to modern digital music recordings is far superior to the old records, right? Well, that's not the case in some people's minds. There are many people in the last few years who have come to believe that the venerable 12-inch LP vinyl record represents the peak of music listening. In their minds it beats the digital CD, hands down. And speaking of digital sound reproduction, those MP3 formats pale in comparison to a good quality CD, don't they? There seems to be a backlash brewing, wherein some people prefer an LP to a CD, and many feel the MP3 is the pits.

What's going on here? What, after all, is the best format for music listening among these candidates? I have been skeptical of people who express these recent (retro) preferences, so I did some research to check into the validity of them. As a former acoustic engineer and ongoing music enthusiast, I wanted to delve into the matter and see what the truth is—if possible. I feel that some of the popularity of LPs, as well as the belittling of MP3s is a misunderstanding of the physics of music reproduction, and I sought to learn more.

Let me begin with what I found out about MP3s. This recording format was developed a few decades ago, as a means of reducing the size of the digital file required to store a song (either on a CD or any another digital format). It is based upon a rigorous analysis of the science of psychoacoustics—which tells us that the human ear cannot detect all of the content of a pure, live acoustic event, such as music. We are destined to remain ignorant of some of the information, due to the limitations of our ear and the brain's processing of the electrical signals received from the ear. So those working on developing the MP3 asked: if a CD can essentially reproduce all of the original signal, why record those parts of it that the ear cannot detect? Why waste storage space that is not needed? So recording engineers set out to reduce the size of the music file.

Their task was to measure what part of the original signal we can hear and delete the rest. Why not save just the important parts and throw away the part we can't hear? After many laboratory experiments, the MP3 format was settled upon. It discards nearly 90% of the digitized signal, thereby reducing the required kilobits of storage by a factor of 10! That huge savings is particularly important when you're streaming music over the internet. But what about the information that is lost? Does discarding so much of the original signal cheapen the experience?

More on MP3s and other audio topics next time...