Sound Levels
You have probably seen these series of lines on some audio products sometime in your life, but I bet that you cannot tell me what the different colors mean.
This picture is showing the sound levels of each frequency. The individual lines are measurements of decibels (db), which is a measurement of these sound levels. This is called the meter bridge. The meter bridge is 0’ed off at the level at which the amplifier, or any listening device, can handle.
A meter bridge in a recording software.
When a Sound Engineer is faced with a problem with the audio being too feint or being too distorted, he refers to this chart on his equipment.
0 db to -2 db is on the top and highlighted from red to orange. If the audio is shown hitting this point for a substantial period of time, the audio will clip. Clipping is when the sound will become too powerful for whatever is projecting it. This will cause the audio to have unwanted distortion.
Between -2 db and -4 db is where the audio is the best. The audio is running as loud and full as it can without it being distorted.
Anything below -4 db Is either too quiet or inaudible to the human ear.
Audio Engineers sometimes fix problems with levels by adding compression. Compression either decreases or increases the threshold of the audio. This allows the audio to get in the “sweet spot”.
Sound Engineering 