Authentic Audio—Part 2

A few years ago MP3s were quite acceptable to most listeners—largely because of their convenience—but recently their status has plunged. MP3s use what is termed as a "lossy compression algorithm" (because they throw away 90% of the information). That word "lossy" has been jumped upon as indicating that the listener is being deprived of some crucial information when listening to an MP3. Isn't some of that discarded 90% important? Well, yes, it is a loss of data, but the vast majority of what is discarded, your ear would never detect anyway. Under only the most exacting listening environments would you be able to perceive the difference. However, for most of us, for most of the music we listen to, for most of the equipment we employ, we'd never miss the lost information. So an MP3 really is very close in quality to a CD, despite the current popular belief.

There are a few other relevant factors, however, that rarely get considered, when comparing MP3s to CDs. For one, the quality of the original recording process is of top priority; such as the excellence of the recording equipment, the placement of the recording microphones, the competency of the engineer doing the sound mixing, etc. If any of these are not handled with care, even a top quality CD will provide a pedestrian experience—and it happens quite frequently for recording companies whose top priority is to crank out and sell as many CDs as possible. Not all of them pay attention to these details—especially those aiming for MTV exposure. And then, there's the final criterion: Are you really listening to that music? Many people are so busy multitasking or otherwise not paying attention to their music, that they'd be hard-pressed to tell the difference between an excellent CD and a mediocre one—let alone an MP3.

There is a similar belief that has arisen recently, for those who aspire to being audiophiles: why listen to a digital CD, when you can get the more "authentic" experience from an LP? This thinking comes from the fact that an analog recording gives the listener "everything," while a CD is a digital sample of the music. This reasoning is based on the following consideration: The CD recording process takes 44,000 samples per second, but is still not a continuous offering of the original music like analog is, so the CD (like the MP3) loses something, right? Well, true, for those who are able to hear sounds above 20 kHz—while most of us adults peter out by about 12 to 13 kHz. So, no, there's virtually nothing missing on a CD that your ear could ever discern. In fact, the best thing that is missing on a CD recording, when compared to an LP, is noise: those unpleasant artifacts introduced by the recording equipment or your playback system (such as pops and clicks due to dirt and imperfections on the LP surface or a worn needle).

But the digital CD recording is still sort of artificial, isn't it? After all, it's just a digital sample, not the whole analog signal. Some people declare that it lacks the "warmth" of a good LP. As I wrote above, there really is nothing missing that the human ear can discern. In fact, some experts say that it's likely what they are responding to is not a better sound, but the old familiar analog LP sound that has added things to it: low-frequency turntable "rumble" or other surface noise due to the stylus riding over imperfections on the record's surface.

I think that many people are susceptible to elitist audiophile suggestions. Our desire to acquire the latest and finest "improved" product, so we can stay a step or two ahead of the Acoustic Joneses, makes us vulnerable to the siren song of the marketplace. A high-quality music listening experience comes from far more than purchasing the latest audio fad and then convincing oneself that is the best yet (even when it's LP retro!). This attitude gives short shrift to simply developing good musical taste and attentively listening to what the artists intended to provide.

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...