Hi everyone,
I’ve noticed a faint high-frequency tone on my MacBook Air M4 when lowering the display brightness below ~30%.
It’s not audible during normal use — even in a quiet room — but when listening up close to the top area of the keyboard, the noise becomes noticeable.
To check whether this is normal, I compared several machines:
• MacBook Air M4 (my unit) — faint tone at low brightness, audible from ~10 cm above the keyboard
• MacBook Air M4 (friend’s unit) — exact same behavior
• MacBook Air M1 — similar pattern, but much weaker
• MacBook Pro M4 — completely silent under the same conditions
So it seems that Air models, including previous generations, can produce slight high-frequency noise from the display backlight power circuitry at low brightness. But I’m trying to determine whether the audible distance varies between units.
Steps to reproduce:
1. Set display brightness to 100%.
2. Gradually decrease brightness below ~30%.
3. Listen closely around the top keyboard area.
4. A faint tone may appear or disappear depending on the exact brightness level.
Questions to other Air M4 owners:
• Do you hear a similar faint tone at low brightness?
• How close do you need to be for it to become audible?
• Do your M4 or previous Air models behave the same way?
I’ve already submitted a report through Feedback Assistant.
If more users confirm this, there might be room for Apple to refine the backlight power modulation in a future update.
I’ve noticed a faint high-frequency tone on my MacBook Air M4 when lowering the display brightness below ~30%.
It’s not audible during normal use — even in a quiet room — but when listening up close to the top area of the keyboard, the noise becomes noticeable.
To check whether this is normal, I compared several machines:
• MacBook Air M4 (my unit) — faint tone at low brightness, audible from ~10 cm above the keyboard
• MacBook Air M4 (friend’s unit) — exact same behavior
• MacBook Air M1 — similar pattern, but much weaker
• MacBook Pro M4 — completely silent under the same conditions
So it seems that Air models, including previous generations, can produce slight high-frequency noise from the display backlight power circuitry at low brightness. But I’m trying to determine whether the audible distance varies between units.
Steps to reproduce:
1. Set display brightness to 100%.
2. Gradually decrease brightness below ~30%.
3. Listen closely around the top keyboard area.
4. A faint tone may appear or disappear depending on the exact brightness level.
Questions to other Air M4 owners:
• Do you hear a similar faint tone at low brightness?
• How close do you need to be for it to become audible?
• Do your M4 or previous Air models behave the same way?
I’ve already submitted a report through Feedback Assistant.
If more users confirm this, there might be room for Apple to refine the backlight power modulation in a future update.
