Defence of doctoral thesis in the field of Media Technology, Henna Tahvanainen

New insights into the effect of the seating area on concert hall acoustics 

The title of the thesis is “Analysis and perception of the seat-dip effect concert halls”. In the thesis, room acoustical measurements in concert halls, scale model, and listening tests on the auralised concert halls were conducted to understand the effect of seating on the acoustics of concert halls.

The seat-dip effect is formed when the direct sound from the stage passes between the seats. The results of this thesis show that the seat type, floor raking, and the geometric shape of the concert hall influence the seat-dip effect. The seat-dip effect is essentially low-frequency attenuation and it has been previously thought to be detrimental to the acoustics of concert halls. Many complicated seating structures have been proposed for the amelioration of the effect. However, the listening tests conducted in this thesis show that the low-frequency attenuation caused by the seat-dip effect is mostly inaudible when the concert hall has ample reflected sound energy. Ultimately, the geometric shape of the hall influences the perceived bass response of the concert hall.

The results of this thesis can be applied in concert hall design. It is recommended that for a good low-frequency response the shape of the concert hall should provide many reflections. Furthermore, the seats should have underpasses and the floor should be flat or slightly raking without blocking the underpasses.

Opponent is Dr. Eckhard Kahle, Kahle Acoustics, Belgium

Custos: Professor Tapio Lokki, Aalto University School of Electrical Engineering, Department of Signal Processing and Acoustics

Contact details of the doctoral student: [email protected]

The public defence will be organised via Zoom and on Campus.

The dissertation is publicly displayed 10 days before the defence in the publication archive Aaltodoc of Aalto University. 

Electronic thesis