AVEC, Inc.

On-board Sound Intensity (OBSI) System

What We Do

Phased Array On-board Sound Intensity (OBSI) Road Surface Sound Absorption (ROSSA) Services

NEW Software Feature: "Continuous Mode" OBSI Testing

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AVEC has developed a new module for its OBSI software that allows using the OBSI system to survey long road sections. The Continuous mode OBSI software module is offered as an upgrade to existing customers or as an optional item to new customers. The upgrade allows using the OBSI system in two different modes:

  • Standard OBSI Mode
  • Continuous OBSI Mode
Further details and typical uses of each software mode are described in the document available in the link below.

OBSI System Overview


AVEC, Inc. offers an On-Board Sound Intensity (OBSI) system to measure tire-pavement noise. The hardware and software specifications are based on the current AASHTO standard (T 360-16: Standard Method of Test for Measurement of Tire/Pavement Noise Using the On-Board Sound Intensity (OBSI) Method). The software and hardware components can be bought separately to upgrade an existing system or as a turn-key system including:

  • AVEC's OBSI software with USB remote for easy software control.
  • AVEC's OBSI fixture (see details below).
  • Two GRAS 1/2" intensity probe sets (40GI, four total microphones).
  • Two GRAS 1/2" CCP pre-amplifier sets (26CA).
  • National Instruments 4-channel DAQ (cDAQ-9171, USB-9234).
  • GRAS 42AG sound level calibrator.
  • Semi-rugged laptop (with software pre-installed).
  • Garmin GPS unit and GPS software module for OBSI.
  • Plastic carrying case for OBSI system.
  • Wind screens and cables for intensity probes.
  • DC/AC converter.
  • Required tools.

Other optional items include:

  • Continuous mode OBSI software module.
  • Tachometer.
  • Accelerometers and in-cabin microphones.
  • Standard Reference Test Tire (SRTT).
  • Car mount for laptop.

OBSI Software


The OBSI software is the core of the system, designed with ease of use as the main priority. The layout and functionality reduce user interaction required during the test, and thus help minimize test time. Features like instant run validation and multi-section testing provide a hassle-free user experience. Software features include:

  • Intuitive user interface optimized for testing multiple road sections.
  • Processing and analysis according to latest AASHTO Standard.
  • Instantaneous feedback about validity of runs.
  • Automated report generation (word processor).
  • Figures and results can be easily exported (spreadsheets, word processor, etc.).
  • USB remote for easy software control during testing.
  • Perpetual license (annual renewal not required).

Other software features include:

  • Data acquisition, processing, analysis, and report using same software.
  • Intensity levels can be viewed as a function of time or distance.
  • Automated file naming facilitates data acquisition.
  • Automated microphone calibration procedure.
  • Most settings can be modified for research purposes.
  • Intensity levels available in narrowband and 1/3rd Octave bands.

OBSI Fixture

The OBSI hardware features include:

  • Aluminum and stainless steel construction.
  • Magnetic stabilizer attachment.
  • Adjustable microphone positions (for research purposes).
  • Cable management system.
  • Easy to setup and carry.

Turn-key OBSI system inside carrying case