Independent partitions sum dB attenuations but real ones underperform this

Evidence

The solution is to have two or more partitions that are independent of each other. If the two partitions are truly independent, the total attenuation, or effective sound isolation, is the product of the attenuations of individual partitions, that is, the dB attenuation is the sum of the dB attenuations of the individual partitions. In practice, the partitions are not independent, although the isolation is improved dramatically, but not as much as would be predicted by simply summing the dB attenuations. Coincidence resonances also reduce the effectiveness of a partition, and it is important to ensure that the two partitions have different resonances. This is most easily assured by having them made with either a different thickness or a different material. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2119 (#corroborates, via linked claim)

Categorization

• XREF: connects to: Independent partitions sum their attenuation in decibels — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2119; Averaging across dB versus intensity units changes the computed mean; Uncorrelated source totals ignore the relative phases of signals. (+3 more)

Broader Connections

• Independent partitions sum their attenuation in decibels #corroborates (1.00) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2119
• Adding equal sound intensities yields a 3 dB total increment #exemplifies (0.82)
• Uncorrelated source totals ignore the relative phases of signals. #expands (0.80)
• Averaging across dB versus intensity units changes the computed mean #complicates (0.78)
• Model predicts a minimum in cancellation level via phase-aware vector sums #expands (0.75)