VEHICLE ACOUSTICS - MEASURES, POSSIBILITIES AND LIMITS OF NOISE REDUCTION IN AUTOMOBILES

FAHRZEUGAIUSTIK. MASSNAHMEN, MOEGLICHKEITEN UND GRENZEN DER GERAEUSCHMINDERUNG AM AUTOMOBIL 711Y SEVERAL EXAMPLES ARE CITED IN THIS REGARD. /TRRL/

Following an explanation of the basic principles of acoustics, measures for reducing sound are discussed. On the one hand there is the possibility of attenuation, where the sound is reduced at its place of origin. On the other hand there is insulation, by which the spread of noise is reduced. The insulation of structure-borne and air-borne sound by means of constructional modifications of the engine serves to reduce the noise level of a passenger car to about 80 db(a). More stringent requirements would involve partial or total enclosure of the motor. Further reduction of noise is possible with alteration of the air filter, fitting rubber insulation, reducing the speed of the fan and the use of suitable silencers. In toto the problems of reducing exterior noise in passenger cars are not insoluble, although relatively high financial outlay is required. The noise level inside a passenger car is mainly due to engine and transmission, tyres and wind noise. Structure-borne sound reaching the interior has frequencies of about 40 to 500 hz, special attention must be devoted to so-called "standing waves", where the wavelengths correspond exactly to the interior dimensions of the vehicle (about 100 to 300 hz). The transmission of structure-borne sound is reduced or eliminated by insulation of the interior of the car from the sources of the noise by suitable sound absorbing materials. Several examples are cited in this regard.

  • Corporate Authors:

    Opel (Adam) Ag, Public Relations Stab

    Postfach
    Ruesselsheim, ZZ Deutschland Br   
  • Authors:
    • Burhop, F
  • Publication Date: 1977-10

Language

  • German

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00301042
  • Record Type: Publication
  • Source Agency: Bundesanstalt für Straßenwesen (BASt)
  • Report/Paper Numbers: Monograph
  • Files: ITRD, TRIS
  • Created Date: Nov 27 1979 12:00AM