Definition
The cylindrical coil of fine wire attached to the cone of an electrodynamic loudspeaker. When an audio-frequency current from the receiver or audio amplifier flows through the coil, it creates a changing magnetic field that interacts with the field of a permanent magnet surrounding the coil. This interaction moves the coil — and the cone attached to it — back and forth, producing the sound waves the pilot hears.
Plain English
The small coil of wire inside a speaker that vibrates in response to electrical signals and pushes the speaker cone to make sound.
Context Anchor
Seen in aircraft radio, intercom, and audio system maintenance when troubleshooting a speaker that is weak, silent, or distorted.
Derivation
‘Voice coil’ comes from early radio and telephone work, where this coil reproduced the human voice. ‘Voice’ here means audio signals in general, not just speech — it’s the part that turns electrical audio into mechanical motion.
Why Pilots Care
If the voice coil is damaged or burned out (often from over-driving the audio system), the cockpit speaker will sound distorted or go silent — a real problem for hearing radio calls, ATC instructions, or aural warnings.
Analogy
It works like a tiny motor inside the speaker. The electrical signal makes the coil move, and that movement pushes air to make sound.
Intuition Check
Do not confuse a speaker voice coil with a microphone. A microphone receives sound and turns it into an electrical signal; a speaker voice coil uses an electrical signal to help make sound.
Example Sentence 1
The cockpit speaker went silent after the voice coil burned out from a shorted audio amplifier.
Example Sentence 2
A damaged voice coil in the cockpit speaker can cause distorted radio transmissions.