Close Proximity Method

TSL has developed instrumentation capable of detecting the acoustic absorption of tire rolling noise.

The system consists of measurement microphones (placed outside the vehicle, underbody, and near the reference tire), temperature and environment sensors, signal conditioning units, acquisition boards, and post-processing units.

It allows:

• perform measurements of rolling noise, according to the procedure reported in ISO/DIS 11819-2 “Acoustics – Measurement of the influence of road surfaces on traffic noise – Part 2: The close-proximity method,” 2017 version;
• perform measurements to assess the influence of different pavement types on road traffic noise, taking into account the attenuation effects by sound absorption, both rolling noise, and noise generated by other sources such as exhaust systems, power trains, etc.

The CPX survey instrumentation is also designed to be mounted directly on a road assessment vehicle, with a special trolley, and without shielding, so as to optimize the use of existing instrumentation such as odometer, GPS unit, and cameras. Alternatively, the CPX system can also be placed on the wheels of a trailer dolly in order to perform, with any vehicle, surveys according to ISO 11819-2. Data is acquired through software that detects and manages both noise and temperature values.