Ceilings were established by boxes in staff finalized by the acousticians. The rooms were optimized for the acoustic experience together with sound engineers, architects and acousticians. Other users include audio equipment designers and architectural acousticians. The concert hall was designed in part by renowned acousticians Kirkegaard and Associates. Cathrine Sadolin has continued the voice research together with physicians and acousticians. People that work in the field of structural acoustics are known as structural acousticians. This unknown sound was popularly known by navy acousticians as the "Jezebel Monster". Rayleigh's textbook "The Theory of Sound" (1877) is still used today by acousticians and engineers. It also includes acousticians, audiologists, academics, and those in other disciplines related to audio. JASCO employs acousticians, bioacousticians, physicists, marine mammal scientists, engineers, and project managers. Acousticians study the production, processing and perception of speech. Acousticians are also involved in researching and understanding sound scientifically.