SP395 SoundPro Audio Integrator Form7492 Operation Manual
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the U.S. military, causes the reported Dose to double for every 4 dB increase in the time-
weighted average sound energy. The OSHA (and MSHA) 5 dB standard causes the
reported Dose to double for every 5 dB increase in the time-weighted average sound
energy.
5. Speed – Averaging Speed. Slow (1000 mS time constant) and Fast (125 mS time
constant) averaging speeds are available. Highlight the field and press the control knob to
select the desired averaging speed.
6. Time - Criterion Time. Sets the Criterion Time from 0.1 hour to 24.0 hours, in 0.1 hour
steps. Highlight the field and press the control knob. Rotate the knob to select the desired
time.
7. Weighting– Standard A-weighted, and C-weighted filters are available. Highlight the
field and press the control knob to select the desired filter.
Display Fields -
As the test is running, the elapsed time is shown on the screen. The fields displayed are:
8. SPL – Current Sound Pressure Level, using selected weighting and averaging speed.
9. Leq – Equal-weighted average SPL from start of test. Also referred to as the time-
averaged sound pressure level.
10. Max – Maximum SPL since beginning of test, using selected weighting and averaging
speed.
11. Dose – Noise Dose accumulated since start of test. For example, running at the Criterion
Level for 1/2 of the Test Length would equal a 50% dose.
12. Proj – Projected Dose. This is defined as the dose that would be reported at the end of
the Criterion Time Length, if no more sound above the Threshold was measured.
13. TWA – Time-Weighted-Average. The average sound level for the measured time
period, spread out over the selected workday period (Time), which is normally set to 8
hours.
14. Pause/Resume – Permits test to be paused and then to be resumed.
15. Elapsed Time – Time that has lapsed since the start of the test period.
16. Start/Reset – Starts or resets the test.
Dosimeter Operation
1. Set the Criterion Level. This is the level that will result in a 100% dose reading if
maintained for the entire test. The criterion level is normally 90dB, but may be overridden
if desired.
2. Set the Threshold Level. Any sound below this level does not contribute to the measured
dose. Normally, this is set to 80dB. You can override this setting if desired. It may not be
set higher than the Criterion Level.
3. Set the Averaging Speed. Normally, Slow (1 second time constant) is used, but may be
changed to Fast if desired.
4. Set the Criterion Time. This time is normally set to 8 hours to match the typical work
day. Dosimeter standards are all written around 8 hour work days. All Dose calculations
are referenced to this time.
5. Set the Exchange Rate. This is defined as the number of dB equaling a doubling (or
halving) of the Dose. For example, if a 90 dB dose for 8 hours equals 100%, with a 5dB
exchange rate, an 85 dB dose for 8 hours would equal a 50% dose. 95dB for 8 hours
would equal a 200% dose. This field also displays OHSA, DOD (US Department of
Defense), and ISO, when the Exchange Rate specified by those agencies is selected.
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