Abstract
The paper goes beyond the traditional Loudness and makes the introduction of a new parameter called Perceived Magnitude, developed by Stevens, as an improvement to qualify/quantify acoustic sensations. As a pioneer application we have applied it to quantify some acoustic sources associated to automotive industry. We emphasize the differences regarding Loudness and Perceived Magnitude, and show the right way to compare the results. We measured the sound pressure level spectra of some sources in octave bands and used them to calculate the overall noise in Sones associated to the above parameters as well the usual dB(A). A suggestive and innovative spectral composition weighted by the above functions is introduced starting from the mathematical expression developed by Stevens. This kind of procedure was important for interpretation of the results achieved. Apart from a constant difference of 8 dB, ocasioned by the change of the reference sound, we show the two systems of calculation give very nearly the same overall noise. Finally we are able to discuss the benefits we can achieve with the new parameter in vehicle acoustics taking into consideration some aspects concerning the use of Loudness in the labs and in the Society.