3M SE-401 - Threshold; Upper Limit (UL); B-3: Fast Response to a Tone Burst

Appendix B
Sound Examiner SE-400 Series
37
Figure B-3: Fast response to a tone burst
SPL/L
AS
Sound pressure level. A ratio of one sound pressure to a reference pressure. Because of the enormous dynamic
range of the human ear, the ratio is calculated logarithmically by the formula below, where L
r
is the reference
pressure.
Threshold
An SPL value that defines a lower level of acceptable values. Only SPL samples that exceed the threshold are used
in some calculations.
Upper Limit (UL)
The total time during a study that the SPL exceeds the Upper Limit meter setting.
SPL 20lo g
L
L
r
-----
 
 
dB=
Relative response (dB)
Burst duration, t (milliseconds)