"r" . . . . "http://en.wikipedia.org/wiki/Dissipation_factor"^^ . "belongs to SOQ-ISO" . "Reflectance"@en . . "\\(r= \\frac{P_r}{P_i}\\), where \\(P_r\\) is the reflected sound power, and \\(P_i\\) is the incident sound power."^^ . "Reflectance, or reflection factor for sound power, is the ratio of reflected sound power to incident sound power." . .