| CPC H04R 1/086 (2013.01) [D04H 1/00 (2013.01); D10B 2401/10 (2013.01); D10B 2401/16 (2013.01)] | 24 Claims |
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1. A microphone assembly comprising:
a transducer configured to convert air pressure variations of sound waves into electrical signals;
a transducer chamber configured to house the transducer;
a particle filtration system, wherein the particle filtration system comprises:
an outer support structure having a porosity of less than or equal to about fifty-five pores per square inch (55 PPI),
a filtration layer, wherein the filtration layer is housed by the outer support structure, wherein the filtration layer includes at least one member of a group consisting of at least one layer of an electrostatic media filter, at least one layer of an activated carbon filter, and at least one layer of a nonwoven fabric filter, and
a sleeve disposed between the filtration layer and the transducer chamber, the sleeve configured to grip the filtration layer and prevent the filtration layer from sliding from the transducer chamber,
wherein the filtration layer provides a Minimum Efficient Reporting Value (MERV) rating greater than or equal to thirteen (13), and the filtration layer traps at least fifty-percent (50%) of particles between 0.3 μm and 1 μm, more than or equal to about eighty-five percent (85%) of particles between 1 μm and 3 μm and more than or equal to about ninety percent (90%) of particles between 3 μm and 10 μm, wherein the at least one layer of a nonwoven fabric filter includes an engineered fabric having a random arrangement of filaments or fabrics, wherein the nonwoven fabric filter is at least one member of a group consisting of: a meltblown nonwoven media filter and a spunbound nonwoven media filter, and wherein the filtration layer has a thickness between about 0.1 inches and about 0.5 inches.
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