Sujet Tutoriel pour construire un diffracteur polycylindrique soi-même.
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Studio C&P
830
Posteur·euse AFfolé·e
Premier post
Jean-Pierre B.
1365
AFicionado·a
Bonjour,
avez-vous mesuré ou calculé le taux d'absorption ainsi que l'effet "scattering du poly? (Si vous me donnez les dimensions exactes, je peux le faire
)
avez-vous mesuré ou calculé le taux d'absorption ainsi que l'effet "scattering du poly? (Si vous me donnez les dimensions exactes, je peux le faire
)Acoustic Designer @ Neutral & Natural Acoustics
Consultation Acoustique -> me contacter par message privé.
Studio C&P
830
Posteur·euse AFfolé·e
Bonjour Jean-Pierre,
Voici les dimensions : 60,8x60,8x15
Voici les dimensions : 60,8x60,8x15
Jean-Pierre B.
1365
AFicionado·a
Bonjour,
le diffuseur est calculé pour une longueur de 3,6m tel que préconisé dans l'appendice d'Acoustic Absorbers and Diffusers: Theory, Design and Application par Trevor J. Cox et Peter D'Antonio.
Le "diffusion coefficient" est le le plus important puisque cela représente tous les "polar plots" unifiés.
Bien sûr aucune diffusion temporelle dans ce cas-là...
"The single semi- cylinder produces excellent spatial dispersion, but as can be seen from Figure 1, there is no temporal dispersion. Consequently, the frequency response of the combined incident and reflected sound shows a comb filtered response due to the similarity between the two sounds. This might be why the sound from semi-cylinders has been disliked. The only study to look at this scientifically was a small scale study by Lee10, who came to the conclusion that reflections from modulated surfaces are preferred to those from simple curved surfaces.
Consequently, a good diffuser needs to generate spatial AND temporal dispersion.
While a Schroeder diffuser may be designed purely for its spatial scattering properties, it naturally generates temporal dispersion because of its complex geometry (provided the period width is wide enough). In the case of semi- cylinders, arranging them in a periodic array may not be sufficient to disperse the temporal response, and some form of randomised arrangement is probably needed.
Another critical application for highlighting the differences between spatial and temporal dispersion is stage shells. The side and rear walls of stages are sometimes flat, and sometimes have diffusing surfaces. While there is evidence that diffusing stage shells are useful11, many practitioners still favour flat surfaces."
ACOUSTIC DIFFUSERS: THE GOOD, THE BAD AND THE UGLY
T J Cox, Salford University
le diffuseur est calculé pour une longueur de 3,6m tel que préconisé dans l'appendice d'Acoustic Absorbers and Diffusers: Theory, Design and Application par Trevor J. Cox et Peter D'Antonio.
Le "diffusion coefficient" est le le plus important puisque cela représente tous les "polar plots" unifiés.
Bien sûr aucune diffusion temporelle dans ce cas-là...
"The single semi- cylinder produces excellent spatial dispersion, but as can be seen from Figure 1, there is no temporal dispersion. Consequently, the frequency response of the combined incident and reflected sound shows a comb filtered response due to the similarity between the two sounds. This might be why the sound from semi-cylinders has been disliked. The only study to look at this scientifically was a small scale study by Lee10, who came to the conclusion that reflections from modulated surfaces are preferred to those from simple curved surfaces.
Consequently, a good diffuser needs to generate spatial AND temporal dispersion.
While a Schroeder diffuser may be designed purely for its spatial scattering properties, it naturally generates temporal dispersion because of its complex geometry (provided the period width is wide enough). In the case of semi- cylinders, arranging them in a periodic array may not be sufficient to disperse the temporal response, and some form of randomised arrangement is probably needed.
Another critical application for highlighting the differences between spatial and temporal dispersion is stage shells. The side and rear walls of stages are sometimes flat, and sometimes have diffusing surfaces. While there is evidence that diffusing stage shells are useful11, many practitioners still favour flat surfaces."
ACOUSTIC DIFFUSERS: THE GOOD, THE BAD AND THE UGLY
T J Cox, Salford University
Acoustic Designer @ Neutral & Natural Acoustics
Consultation Acoustique -> me contacter par message privé.
[ Dernière édition du message le 16/07/2019 à 16:52:10 ]
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