Sound absorption of microperforated duct systems

Microperforated sound absorbers have been successfully implemented in suspended ceilings, transparent panel absorbers or other applications. That principle of microperforation has been introduced to further engineering areas such as duct systems where the air flows through the micorperforation. So along with the ventilation aspects, the sound absorption effects need to be taken into account. In that aim, the theory of a microperforated absorber was extended by the effects due to airflow through the microperforation.