acoustic equivalent volume

7.02  acoustic equivalent volume. Alternate method of stating acoustic compliance. Acoustic equivalent volume V_a may be expressed as:

     V_a =  γ p_o C_a =  ρ_o c² C_a

where γ is the ratio of specific heat at constant pressure for air to the specific heat at constant volume, 1.400 at sea level; p_o is ambient pressure in pascals, which, on a standard day at sea level, is 101,325 Pa; C_a is acoustic compliance in m³/Pa; ρ_o is density of air, 1.225 kg/m³ on a standard day at sea level; and c is speed of sound, 340 m/s on a standard day in air with a temperature of 15° C. Unit, cubic meter (m³).

Annotation         Measurement of equivalent volume may involve both adiabatic and isothermal processes. For an isothermal process the ratio of specific heats is unity.