Crackling noises

Thephantomsmask

I've got a month old 2.16ghz MB with superdrive and recently I've been noticing crackling noises coming from the back of the computer, it seems to be from the centre and l haven't had any loss of sound quality so l think it's the fans rather than the speakers. I don't think it was there when l first got the computer so I'm just wondering if it's normal or should l give apple a ring about it? Also since installing the most recent update I've noticed that istat pro is giving me cpu temps of 60 degrees even though the casing is barely warm to touch, l used only get those before when running several apps together and the casing would be really warm.

Sad Professor

How long have you been getting this? Since the 10.4.10 update? Are you sure it's not the speakers? The latest update had a new feature called "iPop" (see here).

Have you checked your active cpu processes in Activity Monitor? Any background apps going crazy?

Thephantomsmask

The crackling noises were definitely there before the 10.4.10 update along with the ipop (i kept thinking it was an alert sound!) which has disappeared since updating. I'm not sure if it's the speakers or not tbh, just that since l haven't had any loss of sound quality and it seems to be coming from the centre of laptop even when it's idling with nothing running that l thought it was the fans. I've been keeping tabs on my apps in istat (should probably use monitor) but none seem to be running excessively, generally what's active is transmission and adium or skype in the background and maybe firefox at the same time.

Sad Professor

Try setting mute and see if it goes away. The "ipop" is caused by the sound card going to sleep and waking back up again so sound quality is not affected as such.

Is the crackling constant? How often do you hear it?

Thephantomsmask

Thanks Sad Professor (are you an REM fan by any chance?) I'll give putting it on mute a shot tonight, the crackling is nearly constant but varies in how loud it is, it's just bugging me that l don't know what it is.

Sad Professor

If you can always hear it then it's probably not "ipop".

Few suggestions/stabs in the dark:

Try turning off Airport (I've noticed it makes a little noise/static on my ibook). You could also try running Hardware Test from the Install cd (hold down D on start-up) and see if it find any problems. Do you have Bootcamp installed, is the crackling there as well? Play around and see if you can narrow down where the sound is coming from and if it's always there.

Any problem with the fans? They kick when it gets too hot?

Thephantomsmask wrote:

Thanks Sad Professor (are you an REM fan by any chance?)

I am indeed

440Hz

*hands up*

This was me a few months ago! With my brand new MBP at the time... Im at work but when I get home ill upload an mp3 for you to listen to, if it is the same sound then the solution is easy. From what you describe im pretty sure its the same problem and a fan issue.

Actually... maybe could you wiretap/audio hijack your noise and post it for us to checkout?

Inspector Gadget

Just on the offchance, does this happen with the mains power disconnected?

(I seem to remember hearing about those Magsafe thingies crackling a while back?)

Gadget

Thephantomsmask

Just after having a bit of a fiddle about with the computer, I tried to capture the sound with audacity but it's not picking it up.

I don't have bootcamp and the crackling (it sounds almost like static noise but not as sharp if that makes any sense) is still there with airport off and the mains unplugged. The hardware check didn't bring up anything and, now that I've been concentrating on it again, I've realised that I still do have the ipop every few minutes (a similiar sound to the pop that the volume icon in the toolbar makes) but both that and the crackling were there before 10.4.10. The fans seem fine, running about 1800rpm most of the time and kicking in when they should, though the noise is only audible when the fans are running at low speed, the crackling doesn't get worse as they get faster. The noise seems to be coming more from the right hand side which is where the ipop emanates from too. I'm pretty stumped as to where to go from here

hupyago

found this site recently ,might find somethin' there
http://appledefects.com/

Sad Professor

Any luck fixing this, OP?

440Hz, what was the solution you were going to suggest?

440Hz

My original suggestion wont apply if its not fan related and it doesnt sound like it is now. When I was trying to narrow down my MBP noises I started by adjusting the rpm and running QuietMBP to rule out CPU related noises. That reduced my 'mooing' and whining and I eventually narrowed it down to the fans. Not sure with this one though, or what apps or out there for MB's.

Pity you were not able to capture the sound. Does it sound like an electrical crackle? is it there all the time? Do you think it is related to audio out perhaps? Is it worse when you are running any particular application?

Sorry for all the questions, just trying to narrow it down a bit!

Thephantomsmask

No luck so far, I read somewhere that resetting the PRAM might work for noisy fans but it didn't help so I'm gonna give apple a bell on Monday about it, there's a service centre somewhere in the wilton area so I can get it looked at during my lunchbreak if needed as I'm working in Cork atm.

440Hz wrote:

Pity you were not able to capture the sound. Does it sound like an electrical crackle? is it there all the time? Do you think it is related to audio out perhaps? Is it worse when you are running any particular application?

Sorry for all the questions, just trying to narrow it down a bit!

It does sound rather like electrical crackling, sort of like trying to tune a radio for lack of a better description, it's there all the time at varying levels of intensity when idling but the fans at full blast or running an audio app/video seem to drown out the noise. It's not related to any particular app but it does get worse if I open several together or do anything cpu intensive until the fan kicks in and drowns it out.

This makes me unsure if it's fan related as I'd imagine it would get worse as the fans get faster if it was, there's no effect on audio playback or recording so I don't know if it's related to the speakers or line out, the only other thing I can think of is that it could be noises from the cpu itself but I don't know if that's possible

Thephantomsmask

Just an update on this... I eventually managed to get my macbook to the service centre in Cork, they close for lunch & don't open on Saturdays so trying to get there involved leaving work half an hour early and getting a taxi, which l finally managed on Tuesday. Anywho, they told me today that the noises are fan related & that they're waiting on a new one from apple so l should have the computer back early next week. Fingers crossed that this will sort it!

Sad Professor

Pesky fans, glad you got to the bottom of it anyway. I hope this is being covered by the warranty?

440Hz

Ah yeah, the old fan thing!! hehe

At least knowing what it is helps. Fingers crossed indeed

Thephantomsmask

Sad Professor wrote:

Pesky fans, glad you got to the bottom of it anyway. I hope this is being covered by the warranty?

Yup, it's under warranty though they did tell me that they'd contact me if they were doing anything that might affect my hdd and that a back up costs €45 which seems really steep, especially when the woman at the desk couldn't tell me if back up meant cloning the hdd or just copying what was in my users folder. I still don't understand why noises from the fan could be worse when idling than when at full blast though!