Many Celestion LF loudspeakers feature demodulation rings to substantially reduce inductive rise as well as harmonic and intermodulation distortion
April 22, 2014
These electrically conductive 'shorting' rings are placed in strategic locations around the magnet gap such that they act as if they were a secondary circuit of a transformer (the voice coil and magnet pole piece being the primary arm of the transformer).
The shorting ring is more effective (than the rest of the magnet assembly) at conducting away the unwanted electrical current thereby reducing inductance (Le) within the motor circuit.Circuit inductance can have the negative effect of reducing the speaker's SPL, when input power is high (so-called power compression). Lower motor circuit inductance = less power compression.