Various Technical Topics on the development of ASEP 10 July 2018 P R E S E N T A T I O N O F INTERNATIONAL ORGANIZATION OF MOTOR VEHICLE MANUFACTURERS Various Technical Topics on the development of ASEP

Acoustic Memory on Perceived Sound and Annoyance Aspects Perception of Sound Acoustic Memory on Perceived Sound and Annoyance Aspects

Acoustic Memory Humans have no memory for sound pressure or the subjective perceived sound volume. (http://www.computational-acoustics.de/html/akustisches_gedachtnis.html#Gedaechtnis) Experiment: When two sounds which differ by 3 dB are presented with a time delay, it is difficult to decide which sound is louder. Reference sound Comparative sound Which sound is louder? 1000 Hz 1000 Hz Only without a break one can "hear" which of the two sounds (by 3 dB) is quieter.

… it not only a question of sound level SOUND or NOISE ? 30 dB 100 dB 60..100 dB 30 dB … what we accept or reject … … it not only a question of sound level 50..95 dB 100 dB

Acoustic Memory SOUND Person individual influence factors Humans analyse permanent incoming sound for information. Decision of Receiver Signal Analysis (Cocktailparty Effect) Pleasure SOUND Person individual influence factors Acceptance Annoyance Thus it is difficult to say, weather the perceived information or the sound level of the signal is rated as annoyance or not.

Acoustic Memory Humans have no memory for sound pressure or the subjective perceived sound volume. (http://www.computational-acoustics.de/html/akustisches_gedachtnis.html#Gedaechtnis) When can humans hear a change in sound level? Reference Comparative Comparative Comparative Sound Sound #1 Sound #2 Sound #3 1000 Hz 1000 Hz 1000 Hz 1000 Hz A difference of 6 dB is audible and will be recognized by everybody. The capability to hear differences is frequency and sound level dependent. But… … is 6 dB a difference or a significant difference?