noise/echo problem through headphone jack?

Er... yes.

I got my iMac yesterday after 10 years of Windows PCs, one I.T. job too many & having a Mac mini for 10 days!

When it comes to audio I found with most PCs you'd get some noise - clicks and whirrs and whines and hisses. Even my main PC's fairly high-end Audigy 2 ZS sound card had some slight noise.

So, one thing that really impressed me with the Mac mini (apart from its size and cuteness!) was the complete absence of electrical noise or interference from the headphone socket, even with the volume on full.

However, after getting my iMac home, spending an hour in gobsmacked awe at the sheer beauty of it, then plugging in my headphones to diddle about with Garageband without annoying my green-with-envy flatmate, I was very disappointed to hear some low but noticeable electrical noise - alternating between a hiss and whine.

Usually this was only really noticeable when no sound was playing, but after 10 minutes wearing headphones for general usage it did get a bit grating. Even with the volume turned right up and down the level of the noise didn't change.

Looking at the system profiler it says that it uses an Intel High Definition Audio chip - this is probably the same one as used on (admittedly, better quality) Intel PC motherboards.

Oh.

Dear.

And there was I thinking I was spending £1,299 on something different and more special.

But have I regretted selling my main PC for £650 (it cost me £1000 to build less than a month ago! And thats without a monitor!)? Naaah... OS X over Windows any day! It's like owning an Amiga again (but thats another story!)

Anyway, what sound chip does the Mac mini and the iMac G5 have? And is anybody else noticing the electrical noise with the Intel iMac? And is there anything I can do about it without having to show my reddening face at the Apple Store again?

20" iMac Intel Mac OS X (10.4.5)

I've sussed it!

Noise and interference on the headphone port in an Intel Mac is caused by the Mighty Mouse!!!

I noticed that the noise changed from buzz to whine when I moved and picked up the mouse. I've got my Mighty Mouse plugged into my keyboard. At first I tried unplugging the keyboard from the iMacs USB port and the noise stopped. Then I plugged it back in, and then removed the mouse from the keyboard. The interference stopped. I then tried plugging the mouse directly into the iMac. Again, that horrid buzzing whining noise and echoes. So it is definitely the mouse!

The noise changes when the mouse's scanning red light switches on and off and during movement.

I've then tried a second Mighty Mouse, the one I bought for my Mac mini. Same thing. And just now I tried another optical mouse, a mini-notebook one. The noise is even worse! It's quite bizarre as well, the noise changes in pitch the further I move it from the desk surface - its like tuning a radio!

This is not good. And I'm quite surprised it is something that has been missed by Apple's engineers. Somebody should have words.

Am I going to be reduced to plugging in a USB ball mouse to avoid noise through my 1 day old iMacs headphone port? Can you actually still get such a device?

Actually, can anybody report on whether the Apple wireless Bluetooth mouse causes electrical noise on the headphone port? And is the noise just on the headphone port or on the inbuilt speakers too? And on the headphone ports dual function as optical audio output?

It was all going so well.

Hohum.


20" iMac (Intel) Mac OS X (10.4.5) I dumped my PCs after owning a Mac mini for 10 days & upgraded it to an iMac!

Let's just face it, and I hope Apple do too... it's not a fault - it's a technical design issue... either that or poor components / bad assembly. Another example of this is the Superdrive in these machines, it makes a right racket!

Hmmm... perhaps I should have gone for a G5. Yesterdays technology maybe, but at least it works.

I do not hear the noise you guys mention here. I am also using the Mighty Mouse with my 17" Intel iMac. Music sounds very clear though quiet parts of my music, both through headphones and my Logitec THX speakers.

I do get a slight pop through my speakers at boot...but every PC I have ever owned did that. Though my Mac Mini didn't...

Oh well.

I was just reading the other thread about audio popping, which my new iMac exhibits, when I came upon your thread. I plugged in my iPod headphones, and I have the Mighty Mouse Whir/Whine as well as lots of popping. If I hold the volume up down and then the volume down down, going between zero and 2/3 volume, I can hear it pop several times there, too. Sitting here with headphones on for 5 minutes now, and it is driving me nuts. Calling AppleCare now...this is not good.

Yep, I've had my iMac 2 months now and tried 3 different USB mice and there's been no change - either in the problem or Apple actually acknowledging the issue, even though I raised it on online support.

I've got a screen problem now (1 pixel line from top to bottom halfway across), and will be taking it back to the store for repair/replacement this week so will mention the noise issue - both the popping/echo sound and the stange USB mouse interference.

I have Apple's wireless mouse and keyboard, and when I use them the headphone experience is blissfully noise-free. But darn it, I want to use the extra buttons and scroll wheel late at night too!

Also, the problem isn't restricted to optical mice. I've got a Wacom drawing tablet here and the output picks up noise from that too. I suppose any USB device doing the right/wrong kind of thing electrically will add to the ... uhm, "ambient" 🙂 ...

My 10 day old 20" iMac has gone back to Apple for investigation of the buzzing noise coming through the headphone socket. Really disappointed with this situation, surely they QA these things before they leave the factory, even I could QA a headphone socket.

I've noticed the same thing with the might mouse. However, one thing that I've noticed with my iMac that no one else has mentioned is that my heaphone plug and external speaker plug (that is the male 1/8th inch end) does not go all the way into the back of the imac. That is, the rubber end of the plug is not flush with the back of the imac. I can still see some of the metal part of the male end of the sticking out. Is this happening to anyone else? If so, couldn't the noise stem from the fact that the headpones or speakers (whatever you're using) are not making a complete or adequate connection in the imac audio in port? Please, someone let me know what they think.

20" imac Mac OS X (10.4.6)

Actually, things look the very same here. No matter what plug I connect, it's not flush with the back of the iMac. Of course, I immediately started wondering if that might have any effect. Fortunately I had a friend with more electrical and audio knowledge to consult, instead of resorting to my own feverish speculation and guessing skills.

In short, the fact that part of the plug is sticking out a bit doesn't make any difference at all. The wole outermost part of the plug (from the second "band" you can see on the plug and outward to the plastic) is for earth, and as long as part of it is inside and in touch with the earth connector in the plug things should be fine audio-wise.

Now, over to something else somewhat interesting. After my friend asking if I had I tried a couple of different headphones with my iMac. My Sennheiser PX 200 are what I normally use, and through them I hear the noise very clearly and strongly. With my iPod earbuds the noise was harder to hear, but I put it down mostly to the buds providing less isolation to outside noise.

But then I connected my Sony MDR-P10 phones. They're large, head-squashing monsters that I've had for more than ten years without managing to destroy them. Anyway, when I listen through them the noise is virtually gone! If I really, really concentrate I think I can hear a hint of it, but it might as well be my mind finding things I expect to hear.

We found two guesses as to why this might be. Either the old Sony monsters have better connectors, or they have higher impedance and because of that don't catch the noise as much/at all. Higher impedance in a spaker/headphone basically means it takes more outgoing volume to get a given amount of volume out of the speaker/headphone.

Better connectors seem unlikely, especially after ten years of careless usage. Higher impedance seems very likely, but we're not certain that it explains the lesser noise. And in any case, it doesn't solve the problem with noise being picked up in the first place.

A small step for one man, in that I can use a pair of phones and my mighty mouse at once now if I really want to, but no step at all for mankind/the problem 🙂 ...

20" Core Duo iMac, 12" Rev A Powerbook Mac OS X (10.4.6)

Has anyone tried the Griffin XpressCable with their intel imac? It's a digital audio cable that's similar to the Belkin PureAV Digital Optical Audio cable. I wondering that if these are essential optical cables, maybe they would take care of some of the noise. Maybe?

I see that several people said that they would report back after taking in their imacs. Unfortunately, no one has bothered to report if their noise issue was fixed. I've checked around the disscussion area and under different threads, this problem is everywhere. Hello, anyone out there?

I had the buzz/whine noise from the mighty mouse . It was replaced with the keyboard. Same noise though, that mighty mouse just seems a bit duff. I have now replaced it with a wired laser mouse which is silent and very fast.