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M1 iMac buzzing whining noise with low display brightness

C

cookiemonster89

macrumors regular
Original poster
Dec 13, 2012
168
206
Hello,

today I received my new M1 iMac and after setting it up I noticed this high pitching sound from the chin area. It sounds like the fans are scrubbing against something and create this noise. I used my iPhone to record this by putting it right under the chin. Could some with an M1 iMac do the same and share the audio file?

turn up to full volume.

Edit: After my second unit has the failure and I tested the feedback from Nejy247 i can confirm it is coming from the display brightness level and not from the fans. Everyone I asked with an M1 iMac could so far confirm the problem to me.
 
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cookiemonster89 said:
Hello,

today I received my new M1 iMac and after setting it up I noticed this high pitching sound from the chin area. It sounds like the fans are scrubbing against something and create this noise. I used my iPhone to record this by putting it right under the chin. Could some with an M1 iMac do the same and share the audio file?

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Take it back and get a replacement.
 
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cookiemonster89 said:
Hello,

today I received my new M1 iMac and after setting it up I noticed this high pitching sound from the chin area. It sounds like the fans are scrubbing against something and create this noise. I used my iPhone to record this by putting it right under the chin. Could some with an M1 iMac do the same and share the audio file?

Dropbox - File Deleted - Simplify your life

www.dropbox.com www.dropbox.com
Click to expand...
Is it the base model?
 
cookiemonster89 said:
No it’s the top one with 16 GB Ram and 1 TB SSD.
Click to expand...
okay. Because I just found out the base model only has one fan so I'm about to return mine. I'm done with Apple lying to their customers so I'll most likely go back to Android and Windows. I could've purchased a Windows desktop with almost the same specs for half the price.
 
throwinrocks said:
okay. Because I just found out the base model only has one fan so I'm about to return mine. I'm done with Apple lying to their customers so I'll most likely go back to Android and Windows.
Click to expand...
Like Android Manufactures or windows PC manufactures don't lie to their customers. Intel lies. AMD lies. Nvidia slows down their mining capability of their GPUs. RAM manufactures lie about RAM speed. SSD manufactures lie about the the SSD cells they use. They cheap out and say they use MLC ssd but instead you get TLC.

Don't act like the other side is pure and kind. You can't make your own PC parts. You will have it buy it from manufactures that cut corners as well and keep hidden details to themselves.

Android is even worse. If you think every Android manufacture does not lie to their customers. Oh boy.

Apple lies. I agree that they should disclose having 1 fan. But you DO have 14 days to return it. That's why they have return dates. Also this is why I watch reviews before bilndly buying.

So what happens when you buy a Windows laptop/PC or android phone and the company lied to you?
throwinrocks said:
I could've purchased a Windows desktop with almost the same specs for half the price.
Click to expand...
Yeah indeed but could you have gotten a 4.5K 500nit P3 display as well for half the price?
No

The M1 Mac mini is a way better buy if you don't care about the display.
 
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cookiemonster89 said:
today I received my new M1 iMac and after setting it up I noticed this high pitching sound from the chin area. It sounds like the fans are scrubbing against something and create this noise. I used my iPhone to record this by putting it right under the chin. Could some with an M1 iMac do the same and share the audio file?
Click to expand...
I would demand a replacement from Apple till you get a machine you are satisfied with. Good luck.
 
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I spoke with Apple and they could exchange it. The new one would arrive as soon as august 3rd. Thats a real bummer so I just send it back and take my money back. Will wait for the 27" replacement then.
 
Hi cookiemonster,

i think i have the same problem. I also think its not a fan noise. Try something out, put your Backlight at full brightness, sound should be gone? And when you put backlight lower step by step the sound should come back.Because for me this “works” and the noise your iMac does, its the same as mine.

Ive also contacted apple support and they will send me a new device. but i think this will not solve the problem, because ive already connected a new M1 iMac and there is the same problem that i have with my first iMac M1 …

i think it could be a wirering problem, bad cables in the house …
 
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Mine does that too - It's coil whine of some sort? But I can only hear it if I put my ear next to the chin. It's not noticeable in normal use. How loud is it for you?
 
on the Frist quiet loud that I could hear it in normal working distance. The second one is a little quieter but if it is super quiet und the brightness is very low I can even then hear it. Normally hear music while working or haven’t window open but for a machine that cost over 2000€ it is a bummer. I will contact apple tomorrow and ask what they can do. Exchange is no solution because with a chance of 99% the new one does the same. So maybe wait until they can fix it and then get a replacement? Other from this I really like the machine.
 
I don't think they can do anything about it, but if they actually can I would like to hear what it is.

The PS5 has the same problem (+ a noisy fan), but it's a LOT louder. Sony says it's normal for electronics to make noises...
 
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To be honest, that's quite 'normal' in electronics. But shouldn't happen in Apple products that come at a premium price. The noise isn't coil whine. Usually I hear people describe it as "the sound of electric current." I believe it comes from the components of the PWM switching circuitry since people had identified its correlation to the brightness of backlight.

Could be caused by a faulty design in component or much more likely a normal component paired with a new design of chassis. The inner space of the chassis becomes an echo chamber of the otherwise ultra-low and inaudible noise.

If it's a faulty component, the fix should be easy. If it's a complication from the new chassis, then it might take many months and lots of money.

Thanks to OP for sharing such fine details. That's what I think Apple users' feedback is always better than any reviews.
 
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This is interesting. I had an M1 iMac for about a week that did the same thing - the screen seemed to emit a high-pitched noise that became louder as the brightness was dimmed; the noise was not loud, but it was noticeable (and therefore a bit annoying) at normal working distance when working in a quiet room with low brightness. I think the new one has the same noise but softer, and I haven't noticed it over the (also very soft, and not annoying) normal fan noise. Both macs were the 2-fan version. But when I was puzzling over the first one I started finding similar high-pitched noises from other electronics, including an LED lightbulb in a standard lamp and my 2020 Intel Macbook Air, though only in certain situations, it seems (when switching from a browser window to a Word document, for example). I have no idea what the cause would be; the sound seemed to be coming from the screen, as with the iMac, but the super-thin Air screen doesn't have much room for amplifying sound. I suspect that some electronic noise is normal (inevitable?) and only noticeable once one starts listening for it – but iMac #1 was noisy enough to cause me to start listening. I had never noticed the noise from the Air or the lamp before then.
 
NeonIbis said:
This is interesting. I had an M1 iMac for about a week that did the same thing - the screen seemed to emit a high-pitched noise that became louder as the brightness was dimmed; the noise was not loud, but it was noticeable (and therefore a bit annoying) at normal working distance when working in a quiet room with low brightness. I think the new one has the same noise but softer, and I haven't noticed it over the (also very soft, and not annoying) normal fan noise. Both macs were the 2-fan version. But when I was puzzling over the first one I started finding similar high-pitched noises from other electronics, including an LED lightbulb in a standard lamp and my 2020 Intel Macbook Air, though only in certain situations, it seems (when switching from a browser window to a Word document, for example). I have no idea what the cause would be; the sound seemed to be coming from the screen, as with the iMac, but the super-thin Air screen doesn't have much room for amplifying sound. I suspect that some electronic noise is normal (inevitable?) and only noticeable once one starts listening for it – but iMac #1 was noisy enough to cause me to start listening. I had never noticed the noise from the Air or the lamp before then.
Click to expand...
That’s unfortunately the nature of electricity: https://mrelectric.com/blog/is-it-possible-to-hear-electricity
Better some electrical noise that won’t be noticed with headphones than not, though. I am curious if it’s to do with the way Apple makes the computers, if they’re batched in a certain way and all of the ones shipped within a certain window are “louder” because of some sort of electrical switching going on that isn’t quite right in the chassis, as Kvic said.
Now I’m slightly worried that the chassis design isn’t all that wonderful, even if it is slim. but I’m doubtful I’ll notice it much.
 
poked said:
That’s unfortunately the nature of electricity: https://mrelectric.com/blog/is-it-possible-to-hear-electricity
Better some electrical noise that won’t be noticed with headphones than not, though. I am curious if it’s to do with the way Apple makes the computers, if they’re batched in a certain way and all of the ones shipped within a certain window are “louder” because of some sort of electrical switching going on that isn’t quite right in the chassis, as Kvic said.
Now I’m slightly worried that the chassis design isn’t all that wonderful, even if it is slim. but I’m doubtful I’ll notice it much.
Click to expand...
I'm not sure it's just electricity - the article you linked to refers to a hum at 50-60Hz; what I'm talking about is much higher pitched (more in the mosquito range). Anyway yes, hope you don't notice anything. For me it was noticeable with iMac #1 (with lowered screen brightness), but with iMac #2 I'm not sure I can hear it even when I listen for it.
 
NeonIbis said:
I'm not sure it's just electricity - the article you linked to refers to a hum at 50-60Hz; what I'm talking about is much higher pitched (more in the mosquito range). Anyway yes, hope you don't notice anything. For me it was noticeable with iMac #1 (with lowered screen brightness), but with iMac #2 I'm not sure I can hear it even when I listen for it.
Click to expand...
I see. Maybe something was off in the first iMac you got. The switch for brightness being a few mm off in the chassis? It’s interesting to think about.
 
cookiemonster89 said:
I spoke with Apple and they could exchange it. The new one would arrive as soon as august 3rd. Thats a real bummer so I just send it back and take my money back. Will wait for the 27" replacement then.
Click to expand...
Smart move! Be just as diligent with your 27" replacement. Apple makes great products, but they don't always get it right. I've learned the hard way.
 
Sound like circuit noise caused by pulse with modulation. Depending on the way Apple is dimming the display, either you lower the current, or you change the on vs off time to average out a brightness level. As you lower the brightness, the on vs off time becomes higher. Thats PWM. The circuit magnetically responds by chattering the wires in some of the coils.
 
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lostless said:
Sound like circuit noise caused by pulse with modulation. Depending on the way Apple is dimming the display, either you lower the current, or you change the on vs off time to average out a brightness level. As you lower the brightness, the on vs off time becomes higher. Thats PWM. The circuit magnetically responds by chattering the wires in some of the coils.
Click to expand...
Exactly what I was going to say. PWM can result in a high pitched whine. For example, some (but not all) LED light bulb circuitry whines when the bulb is dimmed. Faint, but annoying. It can vary between apparently identical light bulbs.
 
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Thank you for the link.
If it's indeed not supposed to be like this I'm going to contact Apple - this was a very expensive Mac after all.

But then again I'm wondering if not all new iMacs have this problem? Would suck to go through the hassle of shipping back this computer and getting a even worse one back.
 
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