An integrated method, which combines Electronic Speckle Pattern Interferometry, impulse response measurements, finite element method simulations, and psychoacoustic tests, is proposed to evaluate the vibroacoustic behavior of a carbon fiber bouzouki. Three of the carbon fiber instruments are manufactured, and one is qualified via interferometric experimental measurements with reference to a traditional wooden bouzouki, which was evaluated for its sound and playability by the proposed method. Psychoacoustic tests were used to evaluate the sound and playability of the newly qualified carbon fiber bouzouki, which was further modeled by the finite element method and simulated. The simulation results agreed well with the experimental measurements. Furthermore, finite element simulation results of the qualified carbon fiber bouzouki were demonstrated with reference to the traditional wooden bouzouki experimental results, providing new findings crucial for the optimization of the manufacturing and the vibroacoustic behavior of the carbon fiber instrument. The proposed integrated method can be applied to a variety of carbon fiber stringed musical instruments.

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Sound power level is the key quantity to describe the noise emission of products and is needed to reduce noise at work, at home, and in the environment, e.g. for promoting and selecting low noise products (Sell and Buy Quiet). Sound power determination based on sound intensity measurements has advantages in non-ideal acoustic environments, e.g. indoors, but outside of acoustic test rooms, and is standardized in the ISO 9614 series. The current version of all three parts of ISO 9614 is their first edition. The advances of technology and knowledge indicate that the whole series should be revised. The improvement of the sound intensity method was investigated regarding a number of aspects. The use of a single spacer up to frequencies, which are outside of the currently usable frequency range, was studied. The effect of electrical noise was investigated to extend the applicability of the method to low noise sources. The discretization of the enveloping surface is discussed in relation to the accuracy grade of the measurements. The possibility to measure with more than one probes is also presented. The results indicate that there is the possibility for a substantial improvement of the ISO 9614 series.