Ten times as many identical sound sources are needed to double perceived loudness

Evidence

In order to double the loudness, we need an increase in SPL of 10 dB. Since 10 log(10) = 10, 10 times the number of sources will raise the SPL by 10 dB. Therefore we must increase the number of violinists in the string section by a factor of 10 in order to double their volume. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 658

Categorization

• corroborated: 2 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 658