Sound Level Meter and Noise Monitoring FAQ

Rental meters all comply with current IEC, ANSI and DIN standards* for Sound Level Meters. In general, the “Type” designation has been superseded by “Class” designation, with higher accuracy, performance and calibration requirements. A Class 1 meter is more accurate than Class 2, and therefore a Class 1 meter is generally preferred in a wide range of testing including Environmental Noise Monitoring, Building Acoustics, for Consulting Projects, and even Workplace Noise testing. Class 1 is also a requirement for any case that may involve litigation. All 831C, 831, 821, and LxT1 meters meet current Class 1 standards. [*Specifically IEC61672-1, IEC60651, IEC60804, IEC61260, ANSI S1.11, ANSI S1.4, ANSI S1.43, DIN 45657 with additional details available.]

We offer for rent Sound Level Meters that measure:

• Acoustic levels including Lmax, Lmin, Lpeak with occurrence date and time
• Acoustic Averages (Equivalent Level Leq, Sound Exposure LE)
• 1/1 and/or 1/3 Octave Band (Leq, Lmax, Lmin) on any meter with OB3 option
• Simultaneous RMS and Peak Frequency Weighting: A, C and Z (unweighted)
• Simultaneous RMS Detectors: Slow, Fast, and Impulse
• Statistical Ln (6 user-selectable Ln s), including spectral Ln on 831C and 831
• Community Noise (LDN, LDEN, LDay, LEve, LNight) on LxT with CN option or all 831C and 821 meters
• Sound Exposure including LXVE, Lxavg, TWA(8), Dose, Projected Dose, SEA, and more on LxT, 821IH, and 831
• Record audio files to determine noise source on 831C and 831
• Weather parameters including wind speed, gust speed, direction, temperature, humidity, barometric pressure on 831C and 831 with appropriate weather sensor
• Location latitude, longitude, elevation on 831C and 831 with GPS

Data is stored internally or on USB flash drive.

Three separate “bins” of data can be collected and stored simultaneously if needed

• Time History: stores fast measurements, available in a selectable time range from 100 ms to 24 hr. Many parameters also available in 2.5 ms to 50 ms blocks on 831C and 831.
• Measurement History: long-term trends over time, selectable 1 m to 24 hr.
• Events / Exceedances: collects and stores additional data when user-defined sound levels are exceeded for a minimum duration, based on fixed or dynamic threshold levels

Likely!  Sound Level Measurements and Metrics are sometimes defined and named in multiple ways.  Let us know what you are trying to measure, and we can help with meter selection.

Rental meters can power via internal AA-Lithium or NiMH batteries (provided), AC wall power or USB port of a computer with included adaptors. Outdoor systems have options to power via external DC, sealed lead acid rechargeable or D-cell packs. 831C- and 821-based units can also power via solar panel.

With any sound meter rental, an accessory kit is provided at no additional charge. This includes a link to electronic manual sets, utility software to set up meters, calibration certificates, and a single-point acoustic calibrator. A 10 ft (3 m) cable is typically included for handheld rental meters, 20 ft for outdoor kits, but specify if a particular length is required. Additional items are available for rent.

With adequate consideration for power and sound recordings if enabled, units can be left out taking data continuously for weeks or longer. Typically, data is downloaded via USB (cable or memory stick) via the included G4 software. 831C-based units can connect via cellular, WiFi, or wired networking. These meters can send real time email or text alerts when levels are exceeded and allow for remote data download data or automatic data file push to SFTP or Dropbox.

Yes!

Check out Larson Davis' Sound Measurement Terminology page.

When running in unattended mode, be sure to turn Power Save features on.

Yes, battery life is slightly reduced when making audio recordings.

When set up appropriately, sound recordings will be stored on a USB drive attached to the meter. We recommend Model 831C meters and kits when sound recordings are desired.

Models 831C, 831, and LxT all offer 2 GB of internal storage. Model 821 offers 8 GB of storage included in base rental, upgradable to 256 GB. A USB flash drive can be inserted in Model 831C for up to 32 GB additional storage. Models with 2 GB internal storage hold over 400 M Leq histories or 4 M 1/1- and 1/3-octave band measurements in internal storage

When storing sound recordings, file size can vary widely and depends on:

• File format (uncompressed .wav files are larger than compressed .ogg files)
• Sample Rate
• Duration of each event sound recording
• Number of events occurring during the test

The following table describes the approximate file size for a 60-second sound recording. The WAV file sizes are accurate to the nearest 50 kB. The OGG file sizes are approximations, since every compressed file will be unique.

Recording File Sizes Per 60 Seconds

The batteries in EPS042 are standard D-cells, and they are not rechargeable.

Yes. To avoid this, when the batteries run low, the unit can be “hot swapped” with new batteries without measurement downtime by replacing 4 on each side of the BAT015 pack at a time. Note that there will be additional noise associated with swapping batteries.