Sound attenuating device using an embedded layer for acoustical tuning
View Patent ↗The present invention includes a layered acoustical system for sound attenuation in a vehicle including an external decorative layer; a moldable fiber backer adhesively adhered to a back side of the decorative layer, the moldable fiber backer further including an engineered fiber blend including one or more types of thermoplastic fibers and having a first density; a moldable lofted sound absorber and vibration decoupling layer including being made from another engineered fiber blend including one or more types of thermoplastic fibers and having a second density that is less than the first density of the moldable backer, a top side of the vibration decoupling layer being adhesively adhered to the second side of the moldable fiber backer; and an intermediate layer embedded in a location within the vibration decoupling layer to achieve a balance point between transmission loss and sound absorption.
1. A layered acoustical system for sound attenuation in a vehicle comprising:
an external decorative layer;
a moldable fiber backer including a first side and a second side, the first side of the moldable fiber backer being adhesively adhered to a back side of the external decorative layer, the moldable fiber backer further including an engineered fiber blend including one or more types of thermoplastic fibers, the moldable fiber backer having a first density;
a moldable lofted sound absorber and vibration decoupling layer including a top side and a bottom side and being made from the same or another engineered fiber blend including one or more types of thermoplastic fibers, the moldable lofted sound absorber and vibration decoupling layer having a second density that is less than the first density of the moldable backer, the top side of the moldable lofted sound absorber and vibration decoupling layer being adhesively adhered to the second side of the moldable fiber backer; and
an intermediate layer embedded in and adhered to a location within the moldable lofted sound absorber and vibration decoupling layer to achieve a balance point between transmission loss and sound absorption.
2. The layered acoustical system of claim 1 wherein the decorative layer is a tufted carpet or a needled non-woven carpet.
3. The layered acoustical system of claim 1 wherein the intermediate layer is an acoustical control layer including a perforated membrane or film, an impermeable membrane, or an airflow resistance layer with preferred air flow control properties.
4. The layered acoustical system of claim 1 wherein the intermediate layer is a perforated film layer made of polyamide and polyethylene and having an unmolded thickness of approximately 0.5 mm, a plurality of approximately 380μ diameter substantially circular perforations, a hole density of approximately 30 holes/in 2 , and an airflow resistance of approximately 900 Rayls.
5. The layered acoustical system of claim 1 wherein the moldable fiber backer has a surface density of approximately 807 gsm, a thickness of approximately 3 mm, and an airflow resistance of approximately 400 Rayls.
6. The layered acoustical system of claim 1 wherein the moldable lofted sound absorber and vibration decoupling layer has a surface density of approximately 1610 gsm, a thickness in the range of approximately 3 mm to approximately 30 mm, and an airflow resistance of approximately 490 Rayls at 30 mm.
7. The layered acoustical system of claim 1 wherein the external, non-tufted decorative layer is a nonwoven carpet with a thickness of approximately 5 mm, and an airflow resistance of approximately 80 Rayls.
8. The layered acoustical system of claim 1 wherein the location of the perforated film layer in the moldable lofted sound absorber and vibration decoupling layer is at a level about ½ to ⅓ the thickness of the moldable lofted sound absorber and vibration decoupling layer away from the top side of the moldable lofted sound absorber and vibration decoupling layer.
9. The layered acoustical system of claim 1 wherein the intermediate layer is a perforated film layer that comprises at least one layer.
10. The layered acoustical system of claim 1 further comprising a second perforated film layer embedded in and adhered to a location within the moldable backer, the layered acoustical system still constructed to achieve a new balance point between transmission loss and sound absorption.
11. The layered acoustical system of claim 1 wherein the intermediate layer is an air flow resistance layer comprising:
a third fiber blend having a density of approximately 90 gsm, a thickness of approximately 0.3 mm, and an airflow resistance of approximately 2000 Rayls.
12. The layered acoustical system of claim 3 wherein the location of the air flow resistance layer in the moldable lofted sound absorber and vibration decoupling layer is at a level about ⅓ the thickness of the moldable lofted sound absorber and vibration decoupling layer away from the top side of the moldable lofted sound absorber and vibration decoupling layer.
13. The layered acoustical system of claim 1 further comprising an air flow resistance layer embedded in and adhered to a location within the moldable backer, the layered acoustical system still constructed to achieve a new balance point between transmission loss and sound absorption.
14. The layered acoustical system of claim 1 further comprising a second air flow resistance layer embedded in and adhered to a location within the moldable backer, the layered acoustical system constructed to achieve a new balance point between transmission loss and sound absorption.
15. The layered acoustical system of claim 1 further comprising an impermeable membrane layer embedded in and adhered to a location within the moldable backer, the layered acoustical system still constructed to achieve a new balance point between transmission loss and sound absorption.
16. A layered acoustical system for sound attenuation in a vehicle comprising:
a moldable fiber cap layer including a first side and a second side, the first side of the moldable fiber cap layer being uncovered, the moldable fiber cap layer further including an engineered fiber blend including one or more types of thermoplastic fibers, the moldable fiber cap layer having a first density;
a moldable lofted sound absorber and vibration decoupling layer including a top side and a bottom side and being made from another engineered fiber blend including one or more types of thermoplastic fibers, the moldable lofted sound absorber and vibration decoupling layer having a second density that is less than the first density of the moldable fiber cap layer, the top side of the moldable lofted sound absorber and vibration decoupling layer being adhesively adhered to the second side of the moldable fiber cap layer; and
an intermediate layer embedded in and adhered to a location within a single layer of the layered acoustical system to achieve a balance point between transmission loss and sound absorption.
17. The layered acoustical system of claim 16 wherein the location of the perforated film layer is in the moldable lofted sound absorber and vibration decoupling layer.
18. The layered acoustical system of claim 17 wherein the location of the perforated film layer in the moldable lofted sound absorber and vibration decoupling layer is at a level about ½ to ⅓ the thickness of the moldable lofted sound absorber and vibration decoupling layer away from the top side of the moldable lofted sound absorber and vibration decoupling layer.
19. The layered acoustical system of claim 16 wherein the location of the perforated film layer is in the moldable fiber cap layer.
20. The layered acoustical system of claim 16 wherein the embedded intermediate layer is a perforated membrane or film, an impermeable membrane, or an acoustical control layer with preferred air flow control properties.
21. A layered acoustical system for sound attenuation in a vehicle comprising:
an external decorative layer;
a moldable fiber backer including a first side and a second side, the first side of the moldable fiber backer being adhesively adhered to a back side of the external, non-tufted and un-backed decorative layer, the moldable fiber backer further including an engineered fiber blend including one or more types of thermoplastic fibers, the moldable fiber backer having a thickness of about 3 mm and a density of about 807 gsm;
a moldable lofted sound absorber and vibration decoupling layer including a top side and a bottom side and being made from another engineered fiber blend including one or more types of thermoplastic fibers, the moldable lofted sound absorber and vibration decoupling layer having a thickness in the range of from 3 to 30 mm and a density of about 1610 gsm, the top side of the moldable lofted sound absorber and vibration decoupling layer being adhesively adhered to the second side of the moldable fiber backer; and
a perforated film layer including a heat activated adhesive on opposite sides of the perforated film layer, the perforated layer having a thickness of about 0.5 mm, a plurality of perforations each having a diameter of about 380μ and a hole density of about 30 holes/in 2 , and an airflow resistance of approximately 900 Rayls, the perforated layer being embedded in and adhered to a location within the moldable lofted sound absorber and vibration decoupling layer to achieve a balance point between transmission loss and sound absorption.
22. The layered acoustical system of claim 21 wherein the location of the perforated film layer in the moldable lofted sound absorber and vibration decoupling layer is at a level about ½ to ⅓ the thickness of the moldable lofted sound absorber and vibration decoupling layer away from the top side of the moldable lofted sound absorber and vibration decoupling layer.