NTi Audio XL2 Sound Level Meter - Manual (Page 231)

231
Appendix
10h 00min 06sec Leq5” = Leq of the time win-
dow from 10h 00min 01sec to
10h 00min 06sec
10h 00min 07sec Leq5” = Leq of the time win-
dow from 10h 00min 02sec to
10h 00min 07sec
Application example:
Display the moving Leq over 5 seconds in accor- •
dance with DIN15905
Measure the moving Leq over 60 minutes in ac-
•
cordance with SLV2007
Fast Time Weighting
Time constant t = 125 ms; the time weighting is
an exponential function of time, which defines
how changes of the instantaneous sound pressure
level are averaged for useful sound pressure level
results. The measurement results are shown accu-
rately for sound sources with a minimum length of
0.5 seconds. Fast time weighting is typically used
for common sound level measurements.
Holding Maximum Level
For tracing of feedback frequencies in the RTA page.
The hold time can be set to 3, 5 or 10 seconds.
Impulse Time Weighting
Time constant increase t = 35 ms; time constant
decrease t = 1500 ms; the time weighting is an
exponential function of time, which defines how
changes of the instantaneous sound pressure
level are averaged for useful sound pressure level
results. The measurement results are shown ac-
curately for sound sources with a minimum length
of 0.1 seconds. Impulse time weighting is used for
impulsive sound sources.
Correction Value k1
Applies to RMS based values (LAF, LAeq, ...). The
correction value k1 is measured or manually set in
the page K
SET of the sound level meter function.
Correction Value k2
Applies to time-weighting setting PK ( = peak). The
correction value k2 is measured or manually set in
the page K
SET of the sound level meter function.