A popular search term in audio is “db meter”. Sometimes people search for terms that they think go together or they have seen or heard it used somewhere. Sometimes there is a combination of words into a phrase that tries to illustrate an audio point or concept. Lets examine each word within the search term “db meter” and see if it the right word or group of words to use in this situation.
Db stands for decibels and is a unit of measure that those in the audio world use to describe intervals or amounts of energy within in a given environment. It is only that: a unit of measure. It does not have any value of its own other than to say it is a unit of measure that is calculated and formed to correspond to the human ear hearing range. A large db number can cause inner ear damage. A smaller db number may be too low to hear the difference in gain jumps. A db is part of a scientifically calculated scale or ratio for human hearing comparisons and even regulations.
What does the db unit mean when it is attached to a number? A db meter measures sound pressure levels.The sound pressure level can be assigned many different units of measurement. Therefore, using a ratio is better for human sense of hearing comparisons. A db unit is a ratio of acoustic power levels expressed in decibels that “comply” within our human hearing range. These are decibels that express a power ratio made for human hearing measurements. For example, a Saturn rocket has a sound pressure (Pa) of around 100,000 Its sound pressure level measured in db is 194. Normal conversational speech has a sound pressure of .02 while the sound level is 60.
Searching for a db meter may be confusing for the clerk at the store, sine we are really measuring sound pressure levels expressed in decibels in our room. Although, if you go to Radio Shack and ask for a sound pressure meter, they will search their product data base and will find no entries in it for “sound pressure meter” If you change your request for a db meter, they will have one for you quickly. It is funny how things work.