Meeting Topic: Electroacoustic reverberation
Moderator Name: Per SJösten
Speaker Name: Lars Olson of Gothenberg Opera House. Mikael Collin and Mattias Winther of Audile Electroacoustics. Ingemar Ohlsson of ADL (also Swedish section treasurer)
Other business or activities at the meeting: Next meeting announced. June 9th - collaboration with Swedish Radio - seminar on Audio over IP and the impact of AES67
Meeting Location: Gothenberg
The Swedish section had the pleasure of meeting in the Gothenburg Opera's rehearsal room.
The shoebox shaped room is used by symphony orchestras, choirs as well as smaller ensembles for rehearsals before performances in the main hall.
Lars Olson who has previously worked as the stage manager talked about the problems associated with the room before the final solution was arrived. The main complaint was that the room was too loud. Even though the reverberation time was relatively short the early reflected energy from the hard surfaces meant that levels became uncomfortable and forced several members of the orchestra to wear hearing protection.
Investigations were made into how the acoustical levels could be reduced yet also retain communication between the various sections of the orchestra as well as a satisfactory musical reverberation.
The proposed solution was to introduce a large quantity of broadband absorption, tuned low frequency absorption as well as diffusion and then complement the relatively dead space with an electroacoustic reverberation system.
A test setup was erected using heavy wool drapes and loudspeakers mounted in trussing. This provided impetus and confidence to go ahead with the plan.
Whilst initially resistant, the orchestra now, after a year of use and fine adjustment, actually enjoy rehearsing in the new environment.
The electroacoustic system is comprised of a large number of distributed, wide dispersion loudspeakers, several cardioid microphones suspended from the ceiling, Yamaha AFC3 matrix and processing and Yamaha multichannel amplification. The processing and amplification occupy only a 28U rack space which is great improvement in power density over similar systems.
Several presets have been created for the various users as well as a 'cathedral' setting which is used to dramatic effect for demonstrations.
A lively and engaged audience posed questions and discussion points throughout the evening. One of the student members stepped up and volunteered to play the Steinway piano which resides in the hall providing us with a valubale musical evaluation of the new acoustics.
Written By: Steven Liddle