Table 2: Three models of AAC technology I, II, and III.

AAC technology I model AAC technology II model AAC technology III model (1) Usage of apparatus Mobile reflective plate apparatus Tunable perforated plate apparatus Both mobile reflective plate and tunable plate apparatuses (2) Mainly controllable acoustic impedance part of liner Reactance part of acoustic impedance of liner Resistance part of acoustic impedance of liner Both reactance and resistance parts of acoustic impedance of liner