Instruction Manual

Sound Level Meter Types 2245 – Instruction Manual Page 29 of 110
Sound Pressure Level (SPL)
The sound pressure level, L
xy
(SPL)(T
n
) , is defined as the greatest time-weighted sound
level, L
xy
(t) , within a time interval starting at t = T
n
and ending at t = T
n
+ Δ t where:
 x is A for A-weighted, B for B-weighted, C for C-weighted or Z for Z-weighted
 y is F for Fast-weighted, S for Slow-weighted or I for Impulse-weighted
 T
n
= t
0
+ n ·Δ t
 t
0
is some starting time
 n is an incrementing integer
 Δ t is the display update interval, equal to 1 second
The sound pressure level is, in other words, updated every 1 second and is expressed
in decibels (dB).
The symbols used by the sound level meter for sound pressure levels are (for A, B, C
and Z frequency weighting and F, S and I time weighting):
L
AF
(SPL) , L
AS
(SPL) , L
AI
(SPL) , L
BF
(SPL) , L
BS
(SPL) , L
BI
(SPL) , L
CF
(SPL) , L
CS
(SPL) , L
CI
(SPL) , L
ZF
(SPL) ,
L
ZS
(SPL) , L
ZI
(SPL)
Taktmaximalpegel
The Taktmaximalpegel, L
AF
T(T
n
) , is defined as the greatest time-weighted sound level,
L
AF
(t) , within a time interval starting at t = T
n
and ending at t = T
n
+ Δ t where:
 T
n
= t
0
+ n ·Δ t
 t
0
is some starting time
 n is an incrementing integer
 Δ t is the update interval (Taktzeit), equal to 5 seconds
The Taktmaximalpegel is, in other words, updated every 5 seconds and is expressed in
decibels (dB).
The Taktmaximalpegel is not displayed by the sound level meter. It is only used for the
calculation of Taktmaximal- Mittelungspegel.
2.14.2 Timed Broadband Measurements
These measurements are only executed when Start is activated and are paused
when is activated again or when Stop has been activated or when Preset
time has expired, whichever occurs first. The time interval between start and pause/stop
is the Elapsed time indicated as Elapsed . During the measurement time interval,
intermediate results are displayed as if the measurements were paused at the time of
display. When the measurements are paused/stopped, the set of results, including
Latched overload (colour: magenta) are automatically stored and this is held on the
display until either Stop is activated again, or a new measurement is started.