Recent experiences with vibration of stage and audience floors in concert halls

Abstract

Vibration of (wood) surfaces plays a significant role in concert hall acoustics, as confirmed by musicians and music lovers. Many acoustic engineers, on the other hand, tend to have strong reservations against vibrating surfaces, and usually try to minimise surface vibration in order to maximise RT and airborne Strength (G) at bass frequencies. This has lead to a generally accepted preference for massive and stiff surface constructions in new halls. Problems have been known to occur when this general guideline was also applied to the design of wooden floors, in particular stage floors. Despite some good scientific research in this field, a big gap still remains between the vibro-acoustic behaviour of wooden floors and subjective preferences of musicians and audiences. This paper further explores the role of vibrations in concert hall design, and the need for balancing surface reflectivity versus vibration transmission. Recent experiences, including the new Konserthus in Stavanger and the renovation of the Bolshoi Hall of the Moscow Conservatory, will be described as well as vibration measurements carried out on a number of existing stage floors. Some implications for the design of wooden floor constructions will be discussed.