Patent ID: 7961902
Filing Date: 2011-06-14
Classification: H04R

Abstract:
1. A speaker apparatus comprising: a magnetic circuit; a diaphragm having an effective vibration area S a drive cone having an effective vibration area S outer circumferences of the diaphragm and the drive cone are fixed to supporting portions of a frame via a first edge and a second edge respectively; a closed space defined by the diaphragm and the drive cone, the closed space has a volume V; a spring constant of an air spring in the closed space is proportional to (S−S the magnetic circuit includes: a ring-shaped plate; and a ring-shaped magnet including a plurality of unit magnets each of which has a different outer diameter; and a curved surface of the drive cone is disposed parallel to a curved surface that is defined by corners of the plurality of unit magnets, the corners being closest corners to the drive cone.