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Name: Scott S.
Status: Student
Age: 30s
Location: N/A
Country: N/A
Date: 2001


Question:
If I have 3 sound sources located adjacent to each other each with a maximum signal level of 65 dBA, is the cumulative sound level additive?

Do I end up with a cumulative sound pressure level of 195 dBA near these sources?



Replies:
Hi, Scott !!

The sound pressure in this case is NOT cumulative. To be cumulative, the air of a sound box should receive the energy of the second sound box after the first one, and the same for the third. Surely there will be an interference between the pressure waves that tends to cumulate the pressure, but NOT in a linear fashion due to several factors like air viscosity, open or closed room, temperature of the air, etc.

A person talking measures about 50 decibels (dB). A vacuum cleaner measures 70 dB, etc. 10 people talking are NOT ten times louder than only one talking, although the way our ears and brain pick up the sound may indicate the contrary.

Regards

Vince Calder



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