US 11,818,536 B2
Audio devices having low-frequency extension filter
Brent Robert Shumard, Mount Prospect, IL (US); and Thomas Andrew Satrom, Chicago, IL (US)
Assigned to Shure Acquisition Holdings, Inc., Niles, IL (US)
Filed by Shure Acquisition Holdings, Inc., Niles, IL (US)
Filed on Nov. 17, 2021, as Appl. No. 17/528,887.
Claims priority of provisional application 63/115,532, filed on Nov. 18, 2020.
Prior Publication US 2022/0159370 A1, May 19, 2022
Int. Cl. H04R 1/28 (2006.01)
CPC H04R 1/2873 (2013.01) 20 Claims
OG exemplary drawing
 
1. An audio apparatus comprising:
a housing forming an acoustically closed interior space;
a speaker coupled to the housing and configured to emit sound; and
a low-frequency filter disposed within the interior space and configured to filter a plurality of frequency bands within a stiffness-controlled response domain of the audio apparatus, the low-frequency filter comprising a plurality of acoustic pathways, wherein:
each of the plurality of acoustic pathways comprises a first end that is open to the interior space and a second end that is closed; and
each of the plurality of acoustic pathways has a different length corresponding to a different frequency band of the plurality of frequency bands within the stiffness-controlled response domain of the audio apparatus.