Blog 5: A Tempest in a Teapot-- What is "Dynamic Content" and Why Did I Invent a New Definition?

Earlier in this Blog series, I wrote an article about compression. I put forth the idea that compression's use should essentially be limited to one purpose--creating a sense of "increased gravity" (I called this use of compression "gravitization") in a piece of music or a voice narration. I was quick to point out that there are other tools that simply do a better job than compression for which it IMHO is too often misused. Some of those misapplied purposes as I stated were excessive dynamic range, clipping, and overly-aggressive transients.

A fellow audio engineer may have happened to comment: "Kevin, you're wrong. Take a drummer hitting a snare drum with a stick. We don't only want to get the sound of the snare drum, we want to get the sound of the stick hitting the drum. Since that sound is so much softer than the drum itself, we have a dynamic range problem. We need to use compresson to bring up the softer sound of the stick so it can be heard, and that means we need to use compression."

Well, I think it's wrong that I'm wrong. I struggled with this concept when I was a newbie audio mixer, but I came to realize that there is a difference bewteen the range of the loudest note and the softest note in a track and the difference between the decibel levels of each of the sounds inside the track to each other. The concept of music whose loudest notes are too loud compared to its softest notes is called a problem of dynamic range. Unfortunately, I can find no term for the problem in music when certain sounds inside the track itself are too loud compared to sorfter sounds inside the track. So I came up with a term to distinguish this concept from dynamic range: dynamic content. They are different notions. If the dynamic range of a snare's loud thump and the softest sounds the track are, say, 18 decibels--that's pretty dynamic range--the dynamic content between the snare's thump when it's hit and then starts to fade versus the sound of the drummer's stick will be less than that. If the drummer is using a brush to create an even softer "brush work" sound, the dynamic content between the thump and the brush sound will be a second different dynamic content value. And the sound between the thump and the cymbal in the background will be a different one still.

But, as the title to this blog suggests, I think all these competing sounds inside of a single snare track may indeed be a "tempest in a teacup". Here's the point: The overall average dynamic range is automatically taken care of when a compressor is used to emulate increasing the gravitational force upon a song to make it sound "tighter" or "more coherent". Hence, avarage dynamic range as a concept is something an engineer need not worry about. The second type of dynamic range--that caused by single instances of say, a singer momentarily too close to a mic, or a guitarist who loses his mind and crashes a chord so loud it makes the track clip--is better addressed by other techniques such as clip gaining or automation (discussed in the article).

Dynamic content, however, is another notion entirely. And it is addressed far better by a dynamic EQ than a compressor. We'll save the a deep dive into the topic of dynamic EQ for another day, but the critical difference bewteen the two is that while compression reduces the difference between dynamic content equally across the frequency spectrum, dynamic EQ only reduces it surgically at the precise frequencies that the softer sound needs to be augmented. For example, the click of the drummer's stick is typically coming in around 3 to 5 kHz. A compressor, even a multi-band compressor, willl apply its downward compression over a broad swath of the frequency spectrum. It's like doing surgery to extract a specimen with a saw instead of tweezers. In the world of audio, that may bring up unnatrual, unwanted sounds along with the sound of the stick. And that makes the dynamic EQ the better tool of choice --Kevin