Dynamic loudspeaker with two coaxial cones - has common central iron core for both air gaps and small cup radiator behind main cone

摘要

The loudspeaker with two co-axial air gaps and two moving coils has driving acoustic radiators for different frequencies signified by a common central core (4) having two portions (4a,4b) of different diameters with a flange portion (4c) which serves to secure the central core (4) to one of the pole rings (3) via a non-magnetic isolator ring (5). The axial length of the upper portion (4b) is shorter than that of the lower portion (4a). A permanent magnet ring (1) polarises the pole shoes (2 and 3). The lower acoustic radiator is a cone (7) optimised for reproducing bass and middle range frequencies whereas the upper one is cup-shaped (8) having sufficient stiffness to follow the very high acoustic frequencies. A special holder for carrying the loudspeaker in the preferred axially vertical position consists of a hollow column with sound permeable walls topped by a hemispherical wire net.