Patent ID: 9697817
Date: 2017-07-04
CPC Classifications: B29C,B33Y,E04B,G10K

Claim:
1. An acoustic attenuation device extending from a first end to a second end comprising: first and second sheets; a plurality of webs positioned between the first and second sheets and cooperating with the first and second sheets to form a series of sound attenuation chambers containing a volume and mass of fluid; a first panel secured to the sheets and closing the chambers at the first end of the device; a second panel secured to the sheets and closing the chambers at the second end of the device; and first and second openings associated with each chamber and through which excited air resonates, the first and second openings extending through the first sheet into each chamber, the first openings having an invariable cross-section and at least one of the second openings having an adjustable cross-section for varying a resonant frequency of the chamber.