Octave Analyzer Options

Spectrum Options

  • Bandwidth
    The Octave Analyzer performs either whole-octave-band or third-octave-band analysis with center frequencies recommended by ANSI standards.
  • Level Type
    This option determines whether a time-weighted signal level (Lp) or an equivalent signal level (Leq) is measured for each frequency by the analyzer.
  • Frequency Weighting
    SoundMeter provides a means of weighting the spectral content of input signals according to standard A and C frequency weighting curves. These A and C weighting curves are intended to mimic human perception of loudness at two different loudness levels. The desired frequency weighting can be selected from the segmented control.
  • Time Weighting (Lp)
    The Octave Analyzer offers three time weightings for the Lp sound level measurement: Fast, Slow, and Impulse.
    • The fast time weighting computes the exponential-time-weighted average sound level with a time constant of 125 ms.
      The slow time weighting uses a time constant of 1000 ms, or 1 second.
      The impulse time weighting uses a rise time constant of 35 ms and a decay time constant of 1500 ms.
  • Averaging Time (Leq)
    The Octave Analyzer offers three averaging times for the Leq sound level measurement: 1/8s, 1s, and ∞.
    • With 1/8s or 1s, the Leq is calculated over a 1/8 or 1-second time interval, respectively.
      With ∞, the Leq is calculated over the entire duration of the measurement. This is the traditional behavior in prior versions of the Octave Analyzer.

Auto Stop Options

  • Auto Stop
    Octave measurements can be configured to automatically stop after a predetermined amount of time. The elapsed time after which the current measurement will stop can be set in 1 second increments up to two weeks in duration.

Data Logging

  • Log Levels
    SoundMeter can log whole or 1/3-octave Lp and Leq levels for a set amount of time. If Auto Stop is disabled, data logging will continue after the specified duration has been reached and only the most recent data (as much as indicated by the duration) will be kept. When data logging is enabled, logged levels are then displayed in a 2D color surface plot below the spectrum graph.
  • Log Interval
    Octave data can be logged as often as every 0.1 seconds for up to 1 hour, every second for up to 10 hours, or every 10 seconds for up to two weeks. Larger intervals can also be specified in each case.
  • Reset Leq at Intervals
    This option allows the Leq to be reset each time it is logged. With this option, it is possible to log a short Leq of 0.1 seconds for up to an hour.
  • Auto Save Log
    SoundMeter includes the option to automatically save logged sound levels to a data file after the specified duration has been reached. If Auto Stop is disabled, SoundMeter will continue to save the current logged data to a new data file each time the duration is reached. This means that sound levels can be logged at the desired interval for an arbitrarily long period of time.
  • Log File Format
    When logged sound levels are automatically saved, it will be to a file of the specified format.
  • Base File Name
    When logged sound levels are automatically saved, the filename will begin with the specified base file name and end with a time stamp that includes both date and time. The format of the filename's time stamp will be yyyyMMddHHmmss, where y, M, d, H, m, and s refer to year, month, day, hour, minute, and second, respectively.
  • Maximum Auto Saves
    The number of times SoundMeter will automatically save logged data, in a single measurement session, is limited to the value specified here.


  • Notification Events
    Several events are defined which can trigger a local notification. This offers a way to be alerted when an event, such as a sound level exceeding a user-defined threshold, occurs.

Data Export Includes

  • Current Location
    When this option is enabled, the latitude, longitude, and altitude at the time of the measurement will be included in exported data files. Horizontal and vertical accuracy (in meters) will also be included.