Low Noise Sound Level Meter

Low Decibel Noise Level Measurements | Model 831C-LOWN

LD-831C-LOWN-Low-Noise-Level-Measurement-SystemEasily measure very quiet sounds using the SoundAdvisor™ Sound Level Meter Model 831C paired with the Model 378A04 Low Noise Microphone and Preamplifier. Due to the innovative design of the 378A04, which uses a prepolarized microphone and ICP® (constant current) interface, the combination produces a highly portable system that is battery-powered and intuitive to use.

The Model 831C-LOWN configuration is ideal for measurements where noise levels are extremely low, such as very quiet soundscapes and quiet machines.

Because the 831C-LOWN consists of the popular SoundAdvisor Model 831C paired with the 378A04 low-noise microphone, it can be used with the wide range of 831C accessories. For example, use with the DVX012 Ethernet dongle to provide network connectivity or the SoundAdvisor Portable Noise Monitoring System Model NMS044 to create a low-noise portable monitoring solution.


  • No external power supply required
  • 10 Hz to 16 kHz frequency range
  • Highly portable
  • Low power (4 mA ICP)
  • Single channel

Typical Applications

  • Product testing
  • Environmental noise
  • Research and development
  • Anechoic chamber testing
Typical Noise of Model 831C Sound Level Meter with 378A04 Preamp/Microphone Normal Range, 0 dB Gain
Calibration Requires 94 dB re 20 µPa calibrator such as CAL200
Self-generated Noise (typical)
Weighting 0 dB Gain
A 5.5 dB
C 10 dB
Z 18 dB
Alkaline Battery Life Decreased approx 15% when using 378A04
831C-LOWN Included Items
831C Model 831C Sound Level Meter
831C-ACC Accessory kit for Model 831C
ADP074 Adapter for ICP input (BNC)
012A10 BNC cable, 10 ft (3 m)
BNC M-M BNC male to male connector
ADP032 Adapter to mount ½ inch preamplifier to tripod (1/4-20 thread)
Ordering Information
831C-LOWN Low noise system including Model 831C, 378A04 low noise microphone r preamplifier and accessories
Optional Accessories
CAL200 Class 1 acoustic calibrator, 94 or 114 dB at 1 kHz (378A04 must be calibrated at 94dB)
PRM831-FF PRM831 preamplifier with free field microphone (377B02)
PRM831-RI PRM831 preamplifier with random incidence microphone (377B20)
TRP001 Tripod with ADP032 for mounting ½ inch preamplifier
SWW-DNA Software and USB dongle for evaluation and reporting
SWW-DNA-831 Instrument driver for SWW-DNA to provide control, live display, and data translation from Model 831
Sensitivity 450 mV/Pa
-7 (±2 dB) re 1 V/Pa
Frequency Range 10 to 16,000 Hz
Inherent Noise < 6.5 (5.5 typical) dB re 20 µPa
3% Distortion Limit Level (dB re 20 μPa) Frequency
100 dB < 5 kHz
80 dB > 5 kHz
Operating Temperature 14 °F to 176 °F (- 10 °C to 80 °C)
Operating Humidity 0 to 99% relative humidity, non-condensing
Polarization 0 V
Output Voltage ± 2 V peak maximum
ICP constant current 4 to 20 mA (4 mA supplied by Model 831C)
Diameter with Grid 0.52 in (13.2 mm)
Height with Grid 4.02 in (102.1 mm)
Equalization Vent Rear
Weight 1.8 oz (51.3 grams)
Maximum Sound Pressure 130 dB re 20 μPa peak
Mechanical Grid cap and microphone not removable