According to Dictionary.com, “A decibel is a unit used to express the intensity of a sound wave.” Basically, it’s number we use to describe how loud something is. Over the past 19 years of making music my ears have been improving, always getting better able to recognize subtle changes in db levels. Take a look at the following chart to see some common dB levels:
A good piece of gear I recommend people buying is a digital SPL (Sound Pressure Level) meter. If your in the USA just head over to any Radio Shack. They have a decent unit called “Digital-Display Sound-Level Meter”, Model: 33-2055 for $49.99. It runs on a 9V battery. Of course the Shack isn’t the only company that makes them, click here to see Amazon.com’s selection. All SPL meters have a built-in mic and display decibel levels.
If your building a recording studio having a SPL meter is important as you can measure how much sound your neighbors or the outside world is pushing towards you. You can also calculate how much sound proofing you will need to keep your own noise private. Auralex has a nice area on their website called “Bothering Your Neighbors” that shows how much dB you can reduce with each layer of additional building materials: click here
Want to make some money? Bring your SPL meter to any concert, record the dB numbers on video and then go sue the band or venue for hearing damage. There have been numerous law suits exactly like that. I’ve even heard of singers suing venues for hearing damage because of excessive volume levels.
Of course, dB levels also play an important role in audio production. For example when you add some eq to a sound your adding actual volume or decibels. This is important to wrap your head around. If you add 6db of EQ at 2khz your adding 6db of volume to the Master. Working in the digital world, ITB (in the box) you want to keep your individual channel faders low and have them all sum toward the Master. I keep my channel faders at -12db to start and I always keep the Master at 0db. So if you have a vocal on a channel and you add 6db of EQ watch the Master fader level as you are adding 6db to the overall sum of your mix!