Why Whistling Sounds Happen in Bluetooth Earphones and How to Fix Them
Why Does Whistling Occur?
Whistling is typically caused by a positive feedback loop between the earphones’ speaker and microphone. Here are the most common scenarios where it may happen:
1. Holding Earphones in Hand
When you hold earphones outside your ears, the built-in microphone can pick up sounds from the speaker. This creates a feedback loop — much like the screeching sound you hear when a microphone is pointed at a speaker in a karaoke room (KTV).
This is not a regular usage condition and is usually resolved once the earphones are worn properly.
2. Placing Earphones in the Charging Case
If the earbuds are wet from sweat or water, Active Noise Cancellation (ANC) or Transparency Mode may remain active inside the case. When the case has low battery or fails to shut off the earbuds properly, the system may continue amplifying ambient sounds, which can feed back into the microphone, causing a whistling sound.
3. Lying Down with Earphones
When your earphones are pressed tightly against a pillow or soft surface, the front-facing microphone (FF MIC) may pick up sound from the earphone speaker. This can trigger a brief whistling due to the proximity of sound input and output channels.
How to Prevent Whistling Sounds
Here are several effective tips to prevent feedback or whistling noises:
Wear Earphones Properly
Avoid holding earphones in your hand while active.
Insert them correctly in your ears to maintain optimal mic-speaker distance.
Keep Earbuds & Case Clean
Wipe off sweat, water, or debris before placing the earbuds in the charging case.
Moisture buildup can interfere with the microphone's behavior.
Keep Charging Case Powered
Ensure the charging case has at least 10% battery to properly disconnect and manage ANC or Transparency Mode.
Close the lid securely after placing the earbuds inside.
Switch Off Transparency Mode Before Storing
If you use Transparency Mode, switch back to ANC or Normal Mode before placing the earbuds in the case.
This prevents residual sound amplification that may lead to feedback.
Perform a Factory Reset (if needed)
If whistling persists for more than 0.5 seconds, try a reset:
Press and hold the function button on the case for 10 seconds.
Release when the indicator light flashes red five times.
Re-pair the earbuds to your device.
Avoid Pressure While Lying Down
Do not press earbuds tightly against pillows or surfaces that might block mic openings.
Maintain airflow around the microphone holes.
Key Takeaway
Whistling sounds in OPPO Enco earphones are not a defect — they result from certain usage conditions that create a feedback loop between microphones and speakers. By following proper care, storage, and usage tips, you can enjoy uninterrupted, high-quality sound every time.
Still facing issues? Visit your nearest OPPO Service Center or reach out to OPPO Support for expert assistance.