Contents
Introduction to Weighted Filters
Weighted filters are designed to emphasize or attenuate specific frequency ranges and are primarily used to reflect human auditory characteristics. These filters are based on the fact that human auditory responses are not uniform across all frequencies.
Types of Weighted Filters
Various types of weighted filters exist, each tailored for specific situations or loudness levels.
- A-weighted Filter (dBA): This filter is most commonly used to measure human auditory response at low loudness levels. It is frequently applied in situations like traffic noise measurement or office noise level monitoring.
- C-weighted Filter (dBC): This filter reflects human auditory response at high loudness levels, generally above 100dB. It is primarily used in industrial settings involving heavy machinery, or in concert halls.
Less Commonly Used Filters
While B-weighted and D-weighted filters were used in the past, they are seldom applied today. The B-weighted filter was designed for measuring medium loudness levels, and the D-weighted filter had specialized applications, such as in the measurement of aircraft noise.
Common Usage
In most cases, the A-weighted filter is employed when measuring human perceived loudness. This is because the A-weighted filter is particularly effective at capturing the sensitivity of human hearing at lower decibel levels.