The simplest explanation of dynamic range is: “the difference between the loudest & softest sound” in any environment(recorded or otherwise). The human ear is an amazing device! It allows us to perceive an incredibly wide range of volume levels from the quietest thing we can hear(i.e. the threshold of human hearing) to the loudest sounds imaginable & translates these incredibly different sound/air pressure levels into what we perceive as a smooth increase in volume even though the loudest sound is like a zillion times the air pressure of the quietest. Now hang with me a moment… this difference in air pressure is so huge that it requires a special way to measure it: the convenient decibel or “dB scale” (a “logarithmic scale” for the math types) which spares us dealing with lots of zeroes, formulas, & all the boring stuff that made you sleep during math class & join a rock band instead.
Here’s a mind-blower that will have you scratching your head, but it’s a fact & helps illustrate the nature of the dB scale: if you have one roaring Marshall stack & you add a second, you’ll sound twice as loud, right? Wrong! You would need a total of 10 identical Marshall stacks to generate enough increase in air pressure for the owner of the average pair of human ears to perceive the volume as actually sounding twice as loud! This is because of the ear’s ability to accommodate such a huge range of volumes, or more correctly, air pressures & squeeze them down into a manageable range. So if your single stack is 100dB, adding a second will double the air pressure, but only add 3dB of perceived volume increase. In fact, doubling any identical sound source will result in a 3dB increase & tripling it will add another 3db for a total increase of 6dB. OK… enough math. Now for something completely different…
Everybody wants their cd to sound as loud as every other bands’ cd when played consecutively. This is called the “volume wars” & started, in part, because bands figured if their cd was a little louder when it came on the radio that people would notice it more & they’d stand out from the pack, get rich faster, & get more hot babes. So, naturally the next band wanted their’s louder yet & so on. The problem is, any recording medium, be it analog tape or cd, has a maximum level at which anything can be recorded on it before distortion occurs. Therefore, the only way to keep making bands’ cds sound louder is through the use of compression & limiting. Now if I get into a thorough explanation of these two processes I’ll never get you back from the near coma induced by the preceding paragraphs, so suffice it to say that compression/limiting makes all the quiet sounds in your songs louder & the loudest sounds quieter so that in the end, the whole thing sounds louder without exceeding the distortion threshold of the recording media(tape or cd).
While this does make your cd sound louder, it does so at a terrible cost: the elimination of dynamic range, the thing which made all those great, classic recordings we love from the 1970’s sound so natural, exciting, & easy to listen to over & over. Our ears were designed to perceive wide variations in volume, but when all of the soft sounds have been made louder & the loud sounds quieter & the resulting mess is turned up to the limits of the recording media, musicality is lost & ear fatigue results. It’s the equivalent of having a conversation with someone in front of you, but with neither party varying the volume of their voice throughout the discussion & merely SHOUTING AT EACH OTHER CONTINUOUSLY.
Mastering engineers, the guys who take your finished mixes & make the master which will be reproduced as cds, are between a rock & a hard place. They strive for musical results, but their clients keep insisting the end product be as loud as “Johnny So & So’s” cd so it won’t sound “underproduced” by comparison. Nowadays, many albums which could otherwise have been great are ruined by over-compression/limiting for the sake of “loudness” thus making them unlistenable, for any extended period, to most all but those younger than the start of the volume wars in the 1990’s who, sadly, have never known any other sound. My theory, & hope, is that bands will gradually come to their senses & slowly begin to sacrifice volume for musicality & listenability so that all the “volume war” albums will begin to sound dated over the course of the next ten years or so. We can only hope.
P.S. Jack White’s album Blunderbuss debuted April 2012 at Number One on the Billboard 200 chart & was Grammy-nominated for Album of the Year. It also charted with three singles, one nominated. It was mastered with NO dynamics processing! Thanks, Jack. Maybe the tide will turn sooner than anticipated.
P.S.S. Feel free to leave a comment expressing your thoughts about dynamic range & the “volume wars”!