Time History Logging in Noise Monitoring

Sound Level Meter with Time History Logging | Models 831-LOG and 831-FST

831-LOG sound level meter with time history logging

The Model 831 integrating precision sound level meter can be used to record the evolution of sound pressure level over time as a time history (TH). The time history is then used to profile the observation period, which can vary from a couple of seconds to continuous monitoring.

Larson Davis delivers on this need by enhancing the versatility of the Model 831 Sound Level Meter with the addition of Time History Logging Firmware (831-LOG). Users can pre-select from logging periods as small as 20 ms to a full 24-hours. With time periods greater than or equal to 100 ms, up to 58 selectable parameters can be chosen. Selections consist of familiar acoustic metrics as well as non acoustic metric such as battery condition, outdoor microphone performance and meteorological data (831-WTHR).

Special acquisition circumstances may require the user to acquire time based data swifter than 20 ms. For these occasions Larson Davis offers 831-FST Firmware, which adds the additional sampling rate options of 10, 5 and 2.5 ms.


  • 20 ms to 24 hr sample period
  • 2.5, 5, & 10 ms sample period with 831-FST
  • Up to 58 user selectable parameters
  • Log power and weather data


  • View data trends over time
  • Correlate noise data with external events
  • Compute additional metrics
  • Engineering controls – Modify and Re-compute
  • Post-processed event detection
  • Archival record