EOL Test System for Active Sound Generators

In times of electric vehicles and quieter engines, Active Sound Generators (ASG) are used to satisfy car fans with the desire for "real" engine sound. To regain the desired engine feeling, the generators are able to simulate the sound of engines according to the current rotation speed, torque and speed. In the case of electric and hybrid vehicles, they also have a safety-relevant task to fulfil. According to the new NHTSA (National Highway Traffic Safety Administration) regulation, these vehicles must generate an audible sound (Acoustic Vehicle Alert System, AVAS) at speeds of 30 km/h or less to be acoustically perceptible to pedestrians.

The quality assurance of these loudspeakers as well as the related control units of the OEM's are assured with test systems from MCD Elektronik. With the EOLTs with associated flashing station, the Active Sound Generators are acoustically tested for production errors and the ECUs ("Electronic Control Unit") are labeled, programmed and tested in combination with the loudspeakers.


  1. End-of-Line test ASG
    This EOL test system was developed to detect production errors via impedance measurements of specific frequencies during the production of Active Sound Generators. Errors such as tightness of the case, damaged loudspeaker membranes, loose screw connections or grazing voice coils are detected inside the loudspeakers. The testing is performed as follows:

    • DUT assembly on acoustic absorption plate
    • Pulse generation via MCD AudioAnalyzer
    • Electronic impulse covers all hearable frequencies
    • Impedance measurement via MCD AudioAnalyzer
    • Evaluation and pass / fail display via Toolmonitor AudioAnalyzer
    • EOL tester is lockable and mobile because it has been implemented in a transport case
    • Measurement process is controllable from any PC
    • Toolmonitor for evaluating the measurement data has been implemented as stand - alone software

  2. Flashing station ECU
    This station allows a simultaneous contacting and programming of electronic control units (ECUs). Up to six DUTs are automatically labeled and subsequently programmed by a linear axis system and an elaborate mechanical solution. The following test equipment is implemented:

  3. End-of-Line test ECU
    Beforehand programmed and assembled control units for ASG loudspeakers are tested with this EOL test station, which is based on a standardized MCD ULC Rack. The loudspeaker is contacted via an interface and the electronical functions as well as the communication between control unit and ASG is tested. The following test processes are implemented:

    • Contacting via a special plug (32 pins)
    • Testing of CAN communication
    • Testing of automatically fixed labels via 2D barcode scanner
    • Impedance measurement with special test sequences via MCD AudioAnalyzer
    • Short testing time under two seconds
    • Analysis of frequency range via special pulse techniques