iMac without the hum?

The fact that you "think these units also have a fan in them" makes anything you say regarding noise coming from a computer void...sorry.

You obviously don't understand (or most likely, haven't read the entire thread) the problem here.

It's not normal for a computer to make different sounds at different screen brightness levels. It's most likely due to a cheap transformer Apple is using in the iMac's power supply that chokes the power to the screen when the screen dims...and cheap transformers make noise. It is more of a quality issue, to me, than anything really.

Sorry guys, I've been reading stuff all over the net about iMac noise and it seems that most people's expectations are that these machines are supposed to be 100% silent. They are not. And Mike, the reason I said, "i think" these have a fan in them is because mine is so quiet it's hard to tell what the noise really is.

Anyway, I did jump the gun in posting on this thread. Sorry for intruding.

D

iMac 20

I have had a 17" Core 2 at 2Ghz for almost one month and it is totally silent at any brightness level, no hum and the only sound I hear (sometimes) is the disk reading/writing and the optical drive when in use.

I had a 24" iMac and it was dead silent! I played many times with the brightness and yet, nothing.

Had it close to a month, and have the brightness all the way down. Sometimes I hear a little hum, sometimes I don't hear anything. Its pretty quiet compared to the G5 iMac I had and thought was pretty quiet. You always knew when it was on it. This one sometimes its dead silent. Right now, can hear a slight hum.

I bought an iMac 20 this Thursday. I don't think my hearing is that exceptional, but I can hear 3 distinct things on the iMac.

It's a sunday morning at home and aside from the iMac I can hear the central heating (not bothersome), and the fridge (not bothersome).

On the iMac I can hear a slight crackle from the power supply; really quiet. I can hear the fans; a smooth noise, no problem. And I can hear _and FEEL_ through the keyboard the hard drive.

The hard drive (and I checked this in Garageband) is humming a B. One note below middle C on the piano keyboard. When watching a TV show through EyeTV sitting 2 metres away, I can hear the hum. When sitting in the next room, I can just about hear the hum.

When I tilt the base of the iMac, the hum disappears.

iMac 20 - intel Mac OS X (10.4.8)

What happens to the hum if you gently push any of the edges of the panel, without actually making it tilt ?

What happens to the hum if you gently push any of the
edges of the panel, without actually making it tilt ?

Nothing if I squeeze the sides, nor the top or bottom.

But if I tilt it forward as far as it will go, the hum diminishes. I do appreciate though that I've come from a PowerBook with a much slower drive. I just don't know if this hum is normal with 7200 rpm drives.

I think i have the same problem as you Group51. I actually have two hums. One is the screen brightness hum that most 24" iMacs have. But the loudest hum comes from the harddrive. This is my second iMac because I got a new one. The first iMac had 12 dead pixels but that HD didn't make as much noise as this one.

When I start up my iMac you directly hear the vans it seems of the HD rotating all the time and it doesn't dissapear. I read about this on other forums where a guy had the same problem. He asked Apple and it seems to be a production failure. So it's best to bring your iMac back for repairs, I know I will because the hum is quite irritating, specially if you know the first one I had was silent compared to this one.

iMac 24" Mac OS X (10.4.8)

iMac 24" Mac OS X (10.4.8)

Maybe this is not relevant, but my Samsung LCD has this humming that varies depending on the brightness.
Reading discussions on LCD-tv's I've found that some LCD models has this brightnes-hum, others don't. So it appears that Apple, for some of the iMac's, has used LCD screens that has this behaviour?

My 1:st gen Intel iMac 17" has no hum of this kind, but I have an anoying Seagate hd hum....

What kind of hum does your Seagate give ? Mines a Seagate as well but its seems like the ventilator at the HD keeps running all the time and that causes the hum. I might bring my mac back to see if they can fix it

Mine is a WD (Western Digital?)

okay. There's meant to be a "hum" right? Its called the fans.

I dunno, the iMac 20" is Completely silent... but it is as close as i've heard to a silent computer.

There seems to also be an interference pattern eminating from the iMac, my guess is its somehow being released through two coherant sources and creating distinctive minima and maxima around the room. Move or tilt the screen or move your head, and the amplitude of the sound should fluctuate.

Solution to that is just to well... ignore it.. and stick the iMac is a good place so that you're positioned in a minima.

Hi, no hum here on 17" -- just the trouble & strife humming!!!

It's a hum due to the vibration of the drive. When the HD goes to sleep the hum stops. I think it gets worse due to my desk, it is rather light and the vibrations are transfered to the desk. I have another seagate drive in an external enclosure, and it has the vibrations also.
The hum is not THAT bad though, but I have put a thin mousepad under the iMac stand to reduce it.
I will probably buy a more sturdy desk soon that will make it even less noticeable.