Casella CEL CEL-440 - Manual (Page 64)

Criteria 3 ensures that even when the meter is unable to reach a
steady L eq , it will have measured for long enough to have as good an L eq
as the source permits, without measuring for extremely lengthy periods.
Using a typical pink noise source, autoscans take around 20
seconds for all octaves installed, and about 60 seconds for all third
octaves installed. Scanning times can be shortened by restricting the
number of bands to be measured.
A settling time for each band plus a minimum time to obtain an
adequate reading in the band are factory set in the meter and are listed
below. The maximum measurement time per band for Criterion 3 is
always fixed at 4 times the minimum measurement time.
Table 2: Octave Band Settling and Minimum Measurement Times
(Maximum Measurement Time is Four Times Minimum)
Frequency Settling Time Minimum
Measurement
Time
Broadband 1 640 mS 500 mS
Broadband 2 640 mS 500 mS
32 Hz 3500 mS 2 S
64 Hz 2500 mS 2 S
125 Hz 1300 mS 1 S
250 Hz 750 mS 1 S
500 Hz 400 mS 1 S
1 kHz 250 mS 500 mS
2 kHz 250 mS 500 mS
4 kHz 250 mS 250 mS
8 kHz 250 mS 250 mS
Table 3: Third-Octave Band Settling and Minimum Measurement Times
(Maximum Measurement Time is Four Times Minimum)
Frequency Settling Time Minimum
Measurement
Time
Broadband 1 640 mS 500 mS
Broadband 2 640 mS 500 mS
25 Hz 3500 mS 2 S
Page 64 - CEL-440/480 Operators Handbook
Specification