Apple patents audio tech that blocks stray magnetic interference
Apple describes a method for audio devices to detect unwanted electrical currents caused by external magnetic fields. The system creates an opposing voltage to cancel out this interference, ensuring the speaker coil only moves based on the intended sound signal.
In the filing’s own words
An audio device may cancel an induced electrical current and induced voltage, generated by a stray magnetic field, in a transducer coil that is exposed to the stray magnetic field. When an induced voltage due is determined, an opposing voltage is generated and combined with the voltage used to drive an audio transducer to generate sound. When the audio transducer, including the transducer coil, receives the combined voltage, the audio transducer provides an electrical current, based on the combined voltage, the transducer coil drives a sound-generating component (e.g., diaphragm, surround), while the induced voltage due to the stray magnetic field is canceled based on the opposing voltage.
What exactly they claim (claim 1)
1. A method, comprising: in response to detecting an induced electrical current at a transducer coil of a transducer that is operating responsive to an applied electrical current: determining a voltage configured to cancel an induced electrical current at the transducer coil; generating an acoustic output based on at least the determined voltage; and driving the transducer with the acoustic output.
Facts
- Company
- Apple (Apple Inc.)
- Official title
- FIELD CANCELLATION FOR AUDIO TRANSDUCER COILS
- Publication number
- US20260323230A1
- Application number
- 19177476
- Filed
- Apr 11, 2025
- Published
- Oct 15, 2026
- Inventors
- 3
- Claims
- 20
Classified under
H04R 29/003 Electricity & electronicsH04R 3/02 Electricity & electronicsH04R 9/025 Electricity & electronicsMore from Apple in Audio & voice
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Summaries are simplified from the filing’s own abstract and first claim. A patent filing is not a product announcement.
Patent data and drawings: U.S. Patent and Trademark Office (USPTO). Nebula is not affiliated with or endorsed by the USPTO.