Measuring Reverberation Times in Active Acoustic MIMO Systems

Tag / Zeit: 18.08.2021, 09:20-09:40
Raum: Strauss 2/3
Typ: Regulärer Vortrag
Session: Raumakustik 2
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Zusammenfassung: A modern way of implementing variable acoustics into multi-purpose venues are active acoustic systems. With spatially distributed loudspeakers and microphones the recorded, then delayed and processed sound is played back to influence the room characteristics. In most cases all microphones are connected to all speakers which results in a MIMO system. To verify whether the system is running properly the reverberation times are measured in different system tunings. These measurements can be conducted system internally, which implies the measurement not being ISO 3382-1 conform. To empirically examine if the results of measuring ISO conform correspond to measuring internally, two venues with existing active acoustics have been analyzed.Measurement signals were played from all speakers serially and all microphones recorded simultaneously (serial MISO measurement). Due to the large amount of measurements, the averaged octave means of the reverberation times match the ISO conform measurements from 500Hz to 2kHz. The main difference to the ISO measurements is a larger variance. Measurements conducted over relatively short and long paths vary more than mean signal length measurements. Therefore, a subset of microphone and loudspeaker pairs can be chosen to provide equally valid results. Further time shortening can be achieved by using overlapping sweeps.