User:Lindseykoehn/Weighting filter

I noticed that Frequency weighting redirects to this page. Is there another page with more information on frequency weighting? I also think it could be beneficial to go into more detail beyond just A-weighted. Lindseykoehn (talk) 02:34, 24 September 2020 (UTC) I have been looking for new citations to add some more information and credibility to this page. Let me know your thoughts on the following links. https://www.explainthatstuff.com/soundlevelmeters.html, http://hyperphysics.phy-astr.gsu.edu/hbase/Sound/acont.html, http://www.acoustic-glossary.co.uk/frequency-weighting.htm. Lindseykoehn (talk) 20:20, 12 October 2020 (UTC) (on the talk page)

B-curves: B curves filter out more medium loudness levels when compared to an A curves. This curve is rarely ever used in the assessment or monitoring of noise levels anymore.

C-curves: C curves differ from both A and B in the fact that they filter less of the lower and higher frequencies. The filter is a much flatter shape and is used in sound measurement in especially loud and noisy environments. A weighted curves follow a 40 phon curve while C weighted follows a 100 phon curve.

The three curves differ not in their measurement of exposure levels, but in the frequencies measured. A weighted curves allow more frequencies equal to or less than 500Hz through, which is most representative of the human ear.

Measuring Sound with Weighting:

There are a variety of reasons for measuring sound. This includes following regulations to protect worker's hearing, following noise ordinances, in telecommunications, and many more. At the basis of sound measurement is the idea of breaking down an incoming signal based on its different properties. Every incoming sinusoidal wave of sound has a frequency and amplitude. Using this information, a sound level can be deduced from the root-sums-of-squares of the amplitudes of all the incoming auditory information. Whether using a sound level meter or a noise dosimeter, the processing is somewhat similar. With a calibrated sound level meter, the incoming sounds are going to be picked up by the microphone and then measured by the internal electronic circuits. The sound measurement that the device outputs can be filtered through an A, B, or C weighting curve. The curve used will have slight effects on the resulting decibel level.

Sound:

Sound has three basic components, the wavelength, frequency, and speed. In sound measurement, we measure the loudness of the sound in decibels (dB). Decibels are logarithmic with 0dB as the reference. There are also a range of frequencies that sounds can have. Frequency is the number of times a sine wave repeats itself in a second. Normal auditory systems can usually hear between 20 and 20,000 Hz. When we measure sound, the measurement instrument takes the incoming auditory signal and analyzes it for these different features. Weighting filters in these instruments then filter out certain frequencies and decibel levels depending on the filter. A weighted filters are most similar to natural human hearing. This allows the sound level meter to determine what decibel level the incoming sound would likely be for a normal hearing human's auditory system.