Patent ID: 9082388
Filing Date: 2015-07-14
Classification: G10K,H04R

Abstract:
1. Apparatus, comprising: an active noise reduction (ANR) earphone, comprising: ANR circuitry comprising a passageway acoustically coupling the acoustic driver and an ear canal of a user; wherein the acoustic driver is oriented so that a line parallel to, or coincident with, an axis of the acoustic driver and that intersects a centerline of the passageway intersects the centerline of the passageway at angle θ>±30 degrees and wherein the microphone is radially positioned between a point of attachment of a voice coil to an acoustic driver diaphragm and an edge of the acoustic driver diaphragm; and wherein the passageway has a ratio or less, where A is the open cross sectional area of the passageway and l is the length of the passageway; wherein the passageway acoustically seals with the ear canal at the transition between the bowl of the concha and the entrance to the ear canal to form a cavity; wherein the acoustic mass M of the passageway is or less, where ρ is the density of air, A is the open cross sectional area of the passageway and l is the length of the passageway; and wherein the absolute value of the mass impedance |z| of the passageway is or less at 100 Hz and or less at 1 kHz, where |z|=Mf, where ρ is the density of air, A is the open cross sectional area of the passageway and l is the length of the passageway.