Comfort Equations Overview

Comfort equations integrate elementary psychoacoustic indicators into a global indicator of annoyance or unpleasantness. The included psychoacoustic indicators are:

• Level in dB(G)
• ISO532-1 Loudness (phon)
• N5 (sone)
• Sharpness (acum)
• DIN45692 Sharpness (acum)
• Roughness (asper)
• Fluctuation Strength (vacil)
• Psychoacoustics annoyance (Zwicker)
• Polynomial comfort equation

The first comfort equation is Widmann's Psychoacoustics Annoyance (PA), and cited in Zwicker and Fastl, 1990:

PA = N.(1+(w_s² +w_fr²)^1/2)

w_s = max(s-1.75,0.0).0.25.log₁₀(N+10)

w_fr = 2.18 / N^0.4 . (0.4 . F + 0.6 . R)

Where S is the sharpness in acum, N is the loudness in sone, F is the fluctuation strength in vacil, and R is the roughness in asper.

The second comfort equation is a customizable polynomial relationship between acoustic comfort and psychoacoustic indicators:

Comfort indicator = a.N^b + c.S^d + e.R^f +g.F^h + i.G^j

Where S is the sharpness in acum, N is the loudness in sone, F is the fluctuation strength in vacil, R is the roughness in asper and G is the level in dB(G). The constants a, b, c, d, e, f, i and j are set up by the user in the computation profile editing window.