Have you ever tried to set up your sound system around how a CD sounds? Setting the system overall EQ this way is fine. But, if you put in a CD (or iPod if you’re under 30), then turn up the faders til the meters hit zero; now turn up the amp so that the music fills up the room until it’s just a little too loud (you’ll want to have a little bit of headroom), then wait for the band to start playing… the band seems so much quieter! Why?

Recorded music, well digital recorded music has a maximum volume limit before it distorts. Analog has a limit too, but analog distortion sounds good. Just ask your local youth group guitar player. Chances are his guitar amp distorts when he plays too loud. And chances are he likes it. If you like it or not is not part of this discussion.

Digital music is all 1′s and 0′s. Since CDs are 16 bit, you have a volume between 0000000000000000 (16 zeros which is silence) and 1111111111111111 (16 ones which is the max volume). CDs are also sampled at 44.1khz.  All that means is that 44,100 times every second, your CD player spits out a volume value, and your speaker reproduces that. Since you hear a different volume 44,100 times a second, it sounds continuous, or like music, much like a movie is made up of 29 images a second, but it looks like motion to your eyes.

Have you ever compared the volume of your favorite Beatles song to today’s top 40 hits? Notice the huge difference in perceived volume? Since the invention of the CD, the industry has tried to make them louder and louder within the digital limits. This is part of the Mastering process. Part music, part science, a compressor/ limiter is used to get the music as loud as possible.

Try playing recorded modern music (not classical music or bluegrass or anything) through your system, and watch the meters. Notice how there is very little movement? It is constantly spitting out values that are as close to the maximum value. Now, at your soundcheck with the band, you’ll see the meters bounce up and down a lot more. There is much more dynamic range with the band.

When I would tour with Christian bands and have to use a church sound system, often the sound guy would put on some Christian rock band’s CD and ‘show me’ how their system was way more than loud enough. It was a fight trying to explain that comparing a CD to a live band was an apple to oranges comparison. I would constantly fight to get enough volume for a rock show. In 8 years, I found only 3 churches that had an adequate concert system. Hopefully this helps sheds some light on why your system needs more headroom for the band than it does for your recorded music.