This project was the acoustic renovation of a multi-functional lecture hall in a university. The large stepped space had long reverberation time, especially prominent mid-low frequency echo, resulting in poor speech intelligibility. Students in the back row often could not hear the lecturer clearly, and the multimedia audio effect was also poor, which could not meet the daily teaching and academic report needs.

The design team adopted a combined scheme of grooved acoustic panels and perforated acoustic panels for the side walls and back wall treatment. Based on the Helmholtz resonance principle, the two panels are matched according to the space volume and acoustic indicators, targeting the 250Hz–1000Hz mid-low frequency noise that is common in large classrooms and difficult to solve by ordinary materials. With the rear air cavity and mineral wool backing, the overall NRC reaches 0.90, realizing full-band sound absorption and optimizing the sound field uniformity of the whole venue.

The wood veneer panels have a simple and atmospheric appearance, which fits the solemn and pragmatic style of university teaching buildings. After the transformation, the acoustic test shows that the reverberation time is reduced to the optimal range for teaching speech, the language clarity is significantly improved, and the sound pressure level difference between the front and rear rows is controlled within 3dB. It can well meet the needs of daily teaching, academic lectures and small-scale reports, and effectively improve the classroom teaching effect.