What is “dBA”
When we say “dBA” we are referring to “A” weighted reading as read from a sound level meter.
A sound level meter measures sound pressure. The meter has a “weighting” switch such that the dB level shown on the meter can be switched to “A” weighted or “C” weighted.
“A” weighted readings are adjusted by the meter for the frequency (pitch) of the sound. “C” weighted readings are not adjusted.
The reason ”A” weighted readings are adjusted lies to the fact that the human ear does not perceive the same sound pressure level at different frequencies as the same loudness. Specifically, a sound pressure level at low frequency is not perceived as loud as the same sound pressure level at higher frequencies. We might say that “dBA” is a measure of loudness.
- Meter should be set to “A” scale
- 100 ft. from the sound source or race car
- Testing should be done with one car on the track at a time. Multiple cars on the track will raise dB reading.
- If there were 2 cars on the track at the same time in the same location, the readings would be 3 dB higher
- Walls and bleachers may create a sound bounce thus giving an inaccurate reading.
- Race day readings will be higher because of multiple cars on the track at the same time.
- Some Track owners track dB levels at the property line
For track owners needing advice and help on developing a sound reducing program or racers and engine builders wanting to better understand how using the right kind mufflers won't hurt your performance please contact us.