Sound power level measures a source independent of surrounding acoustic context
Evidence
The sound power level is a measure of the total power radiated in all directions by a source of sound, and it is often given the abbreviation SWL, or sometimes PWL. The sound power level is also expressed as the logarithm of a ratio in decibels and can be calculated from the ratio of the actual power level to a reference level of 1 picowatt (10-12 W) as follows: where wactual = the actual sound power level (in watts) and wref = the reference sound power level (10−12 W) The sound power level is useful for comparing the total acoustic power radiated by objects, for example ones that generate unwanted noises. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 185
Categorization
- DEFINE: Establishes the precise definition of SWL/PWL and its reference level of 1 picowatt.
- corroborated: 4 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 185
- XREF: connects to: Strength G measures how room scale dilutes sound energy independent of T60; Sound power and intensity levels are unaffected by source correlation, unlike pressure level; Sound power level can be derived by dividing intensity by radiating area (+2 more)
Broader Connections
- Sound power and intensity levels are unaffected by source correlation, unlike pressure level
#expands(0.85) - Sound power level can be derived by dividing intensity by radiating area
#expands(0.80) - Room boundaries alter a sound source’s radiated power, not just its perceived sound
#complicates(0.80) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2134 - Reverberation multiplies perceived speech loudness well beyond measured level gains
#complicates(0.72) — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 2058