Caractérisation du rayonnement acoustique d'un haut-parleur monté sur une enceinte parallélépipédique allongée. Application a une barre de son.

Abstract : The radiation from a loudspeaker mounted on a box shaped enclosure is usually characterized by measurements or simulations based on finite element method. However, these reference methods are still very expensive and do not allow for a physical interpretation of the results. In this manuscript, two analytical models are proposed to predict this radiation, within the framework of the application to a sound bar. The first model consists of assimilating the sound bar geometry to a spheroid. In this way, the variables are separated and an analytical solution can be found in the form of a sum of spheroidal harmonics. The calculation for a circular loudspeaker on the spheroid, as well as a harmonic truncation criterion, is detailed. Each step of the method will be described, as well as the comparison of the results with the reference methods. The calculation for a circular loudspeaker on the spheroid and the implementation of a harmonic truncation criterion will be developed. This model works well at low-frequency, but cannot account for the diffraction phenomena, which come from the enclosure and appear at high-frequency. Therefore, we have developed a second analytical model based on an integral formulation of the diffraction. This model is seen as a set of secondary sources located on the edges of the enclosure. It will be shown how to establish this model and how it can be implemented. This model allows us to interpret the radiation of a sound bar, and therefore allows us to conclude on the validity of the spheroidal model. It also shows how the baffle edges of a loudspeaker enclosure lead to constructive interference effects, resulting in a gain up to 3 dB. These effects also lead to a counterintuitive phenomenon: if the speaker is not centered on the baffle, the direction of maximum radiation intensity tends to shift to the opposite side of the speaker offset on the baffle.
Complete list of metadatas

Cited literature [171 references]  Display  Hide  Download

https://pastel.archives-ouvertes.fr/tel-01713244
Contributor : Abes Star <>
Submitted on : Tuesday, February 20, 2018 - 1:27:05 PM
Last modification on : Thursday, May 2, 2019 - 10:36:52 AM
Long-term archiving on : Monday, May 21, 2018 - 12:41:33 PM

File

65310_ROGGERONE_2018_archivage...
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01713244, version 1

Citation

Vincent Roggerone. Caractérisation du rayonnement acoustique d'un haut-parleur monté sur une enceinte parallélépipédique allongée. Application a une barre de son.. Acoustique [physics.class-ph]. Université Paris-Saclay, 2018. Français. ⟨NNT : 2018SACLX005⟩. ⟨tel-01713244⟩

Share

Metrics

Record views

747

Files downloads

425