Definition
A loudspeaker in which the steady magnetic field is supplied by a permanent magnet rather than an electromagnet. An audio-frequency current from the radio or intercom flows through a voice coil suspended in this fixed magnetic field, causing the coil and the attached cone to move back and forth and produce sound waves.
Plain English
A speaker that uses a built-in magnet (not one powered by electricity) to make its cone vibrate and produce sound when an audio signal is applied.
Context Anchor
Seen in aircraft electrical, audio, radio, and intercom system descriptions, especially when identifying or replacing speaker components.
Derivation
Permanent magnet' means a magnet that holds its magnetism on its own without needing electric current to maintain it. The name simply tells you which type of magnet supplies the field inside the speaker.
Why Pilots Care
Delivers clear audio for radio communications without extra power draw for the magnet.
Intuition Check
Permanent does not mean the speaker is permanently installed in the airplane. It means the speaker uses a magnet that stays magnetic, rather than a magnet that must be electrically powered to work.
Example Sentence 1
The cabin announcement system uses a permanent magnet speaker mounted in the overhead panel.
Example Sentence 2
Maintenance replaced the permanent magnet speaker after audio became distorted.