=> approximately 1.5 db(A) shall be added to the highest value, resulting inģ. The difference between octave (4, 5) and 3 is The resulting value from octave band 4 and 5 can be added to octave band 3 => approximately 2.5 db(A) shall be added to the highest value, resulting inĢ. Adding octave band 4 and 5 ( check this link) The resulting db(A) sound pressure can be calculated by logarithmic adding (adding signals with different strengths) of the sound pressure for each octave.ġ. The decibel C filter is practically linear over several octaves and is suitable for subjective measurements at very high sound pressure levels. X = the weighted sound pressure level (dB)Īnyway - dBA (or dB(A)) is commonly used. 'the A weighted sound pressure level is x dB' Note! The abbreviation dBA or db(A) is not recognized by SI.

Measurements made with this scale are expressed as dB(A). With the dB(A) filter the sound level meter is less sensitive to very high and very low frequencies. dB(A) roughly corresponds to the inverse of the 40 dB (at 1 kHz) equal-loudness curve for the human ear. Common filters areĭownload and print Sound Pressure Level - db(A), dB(B) and dB(C) criteria chart dB(A) To compensate for the human hearing sound meters are normally fitted with filters that adapts the measured sound response to the human sense of sound. Knowledge about the human ear is important in acoustic design and sound measurement. Regarding noise - higher sound pressures are therefore more acceptable at lower and higher frequencies than in the mid range. The human ear is more sensitive to sound in the 1 to 4 kHz frequency range than to sound at very low or very high frequencies.

Decibel scale who made it