Sound level meter - Frequently Asked Questions

1. Overview of Time-Factorized Noise Level Measurement

Time-weighted noise level (_LX calculation) is a method of expressing noise levels when, within a given measurement period, the time during which the noise level exceeds a certain level accounts for X percent of the measurement period. The LX symbol represents this level. Measuring time-weighted noise level makes it possible to evaluate environments where noise levels are irregular and fluctuate significantly.

 

■ List of measured time-weighted noise levels

By measuring the time-weighted noise level, the following values can be determined simultaneously:

 

■Restrictions during measurement/pause

During or while measuring time-weighted noise levels, some panel switches will become inoperable, as shown in the table below. Please note that turning off the power during time-weighted noise level measurement will forcibly terminate the measurement.

 

2. Measurement Procedure

For instructions on setting basic measurement conditions, please refer to the section on setting measurement conditions.

 

◆Operation

• Set the measurement conditions for noise level measurement.
  Display screen: Optional (Panel switch [LIST])
  Level range: Arbitrary (Panel switch [△・▽ LEVEL])
  Frequency Correction: Optional (Panel switch [A/C/FLAT])
  Dynamic characteristics: Arbitrary (Panel switch [F / S / IMP])
  Measurement value: Arbitrary (Panel switch [LP Leq…])
• Set the measurement time.
  Press the [MEAS TIME] panel switch to set the measurement time. Here, we've set the measurement time to (00:04:10). To set FREE, switch the setting time to 00:00:00. When FREE is set, measurement will continue for up to 100 hours (99:59:60) until you press the [PAUSE/CONT] panel switch. However, please note that you cannot set the measurement time to more than 100 hours.
• Set the sampling interval.
  Press the [Period] panel switch for Function 2 to set the sampling interval. Here, we'll show an example where the sampling interval is set to 5 seconds.
• If the sampling interval is set to 10ms, overflow may occur if the measurement time is too long. Therefore, please set the measurement time to within one hour.
• Furthermore, the overflow time when the measured value changes periodically is shown in the following table. Please refer to the following table to set an appropriate sampling interval and measurement time.

  

• Perform the measurement.
  Pressing the [START] panel switch will begin the measurement. During measurement, a measurement in progress mark will be displayed, and the measurement time setting display will switch to the elapsed measurement time.
• Read the measured value from the digital display.
  The measurement will end once the set measurement time has elapsed. The measurement progress indicator will also disappear once the measurement is complete.

 

■Temporarily suspending measurement

To pause the measurement, press the [PAUSE/CONT] panel switch. When the measurement is paused, the measurement progress indicator will change to a paused indicator.
Also, pressing the [PAUSE/CONT] panel switch again will resume the paused measurement.

 

3. Reading the measured values

The measured values can be displayed using the following procedure. Please refer to the diagram below for details. Note that the display methods for time-weighted noise level, equivalent noise level, single-event noise exposure level, maximum value, minimum value, and maximum value without leveling are also shown here.

 

■Display of measured values via panel switch

With the standard screen displayed, each time you press the panel switch [L _p / L _eq …], the measured values will switch and be displayed in the following order: instantaneous value → equivalent sound level → single-event sound exposure level → maximum value → minimum value → maximum value without level conversion → instantaneous value…

■ Display of measured values in list view

When the standard screen is displayed, pressing the panel switch [LIST] switches to the list display screen. Initially, the equivalent sound level, single-event sound exposure level, maximum value, minimum value, and maximum value without level conversion are all displayed.
Furthermore, pressing the panel switch [L _p / L _eq …] will display a list of all Lx values.

■Screen switching

You can switch between the standard screen and the list screen even while measuring. Furthermore, while the measurement is paused, you can sequentially switch from the standard screen to the list screen, and then to the measured values on the standard screen (panel switch [L _p / L _eq …]).