NOVELTY - Virtual sound source generating apparatus comprises fuel cell stack (100) comprising several cells; sensor unit (102) comprising several sensors for detecting operating state of fuel cell stack; controller (104) for receiving signals of sensor unit and to select chord based on signals or select specific sound based on each signal; sound generator (106) for receiving signal of controller to generate chord based on signals of respective sensors or generate sound selected by controller; and user interface (108) for adjusting type and volume of sound generated by sound generator.    USE - Virtual sound source generating apparatus used for monitoring operating state of fuel cell stack (claimed) of battery for vehicle. Uses include but are not limited to passenger automobiles including sports utility vehicles, buses, trucks, commercial vehicles, watercraft including boats and ships, and aircraft; and hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles    ADVANTAGE - The apparatus monitors real time deviation and deterioration of several cells in fuel cell stack during operation, and expresses results as chord or different sounds, thus allowing driver to easily recognize operating state of fuel cell stack.    DETAILED DESCRIPTION - The sensor unit comprises temperature sensor for detecting temperature of air, hydrogen, and coolant supplied to and discharged from fuel cell stack; output sensor for detecting output signal of fuel cell stack; hydrogen sensor for detecting concentration of hydrogen discharged from fuel cell stack; voltage sensor for detecting voltage according to current when electricity is generated by cells of fuel cell stack; and frequency detector for detecting response frequency of fuel cell stack according to abnormal frequency response method. The sound generator generates chord based on voltages output from respective cells or average value obtained by measuring voltages of several cells. An INDEPENDENT CLAIM is included for generation of virtual sound source for monitoring operating state of fuel cell stack by monitoring operating state of fuel cell stack; selecting specific chord or sound according to operating state of fuel cell stack and generating selected chord or sound; and allowing driver to hear generated chord or sound and recognize whether operating state of fuel cell stack is normal or abnormal.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of virtual sound source generating apparatus.    Fuel cell stack (100)    Sensor unit (102)    Controller (104)    Sound generator (106)    User interface (108)