The Sound Level Meter functions as a standalone device, and you can monitor sound levels by reading the LCD panel.
If you want to collect sound level data, you need to connect the Sound Level Meter to a data-collection interface. To do so, connect the sensor following the steps in the Getting Started section of this user manual. For most classroom activities, the following settings on the Sound Level Meter work well:
- Slide the power switch to the appropriate range.
- Set the time weighting switch to S.
- Set the maximum level hold switch to RESET.
- Set the frequency weighting to A.
For in-depth sound studies, you may need to choose different settings more appropriate for your experiment.
Power/Measurement Range Switch
This slide switch, labeled “O/35–90/75–130,” turns on the sensor and sets the measurement range. When set to the 35–90 range (LO), the sensor is designed to measure sound levels in the range of 35 to 90 dB. When the switch is set to the 75–130 range (HI), the sensor is designed to measure sound levels in the range of 75 to 130 dB. A range warning will appear if the measured sound is beyond the range of the current setting. If this warning appears continuously, set the switch to the appropriate range.
The S/F switch just below the LCD sets the time weighting. For normal measurements set the switch to the slow setting (S). For fluctuating noise, set the weighting to fast (F). In the classroom, you will probably set it to S.
Maximum Level Hold
Setting the MAX/RESET button to MAX sets the LCD display to show the maximum, weighted sound level. In the classroom you will probably set it to RESET, in which case it will continually display the sampled reading. If you are using the Sound Level Meter without a Vernier interface, you can use the MAX setting to record and display only the loudest sound level. Setting this switch to MAX does not affect the output signal sent to the data-collection interface.
The A/C switch is used to set the weighting scale. A-weighted setting is the sound level value that most closely matches that of the human hearing range. It is the weighting scale most commonly used for Occupational Safety and Health Administration (OSHA) and Department of Environmental Quality (DEQ) regulatory measurements. The C-weighted scale is useful for monitoring sources such as engines, explosions, and machinery. This setting would also be used if you use the Sound Level Meter to get the total unweighted sound level of the noise source. For more details about A vs. C weighting scales, see www.vernier.com/til/3500
The sensor comes with a foam windscreen. The windscreen helps reduce the detection of false high signals caused by wind blowing across the microphone. It also protects the microphone from dust and debris.