Background information regarding the 15″ PowerBook G4 audio loop problem

NOTE: Seems as if Apple really got the problem fixed with the Mac OS X 10.4.5 update. Hooray.

I have been suffering from a bug that affects my brand new 15″ PowerBook machine and it seems to affect this machine only as I haven’t experienced that bug on any of my other Macs and I know quite a few people with the same model that recently ran into exactly the same problem. Here is a short sample of the bug that I accidently recorded in my Chaosradio Express 003 podcast episode (german only and a really weird one a it was all about testing things ;). Here is another example I found in an ongoing discussion in Apple’s forums.

Recently, the same bug occured to Adam Curry in episode #309 of his Daily Source Code podcast. I wrote an e-mail to Adam and he talked about it in episode #311 two days later. Another podcaster provided an audio comment on the same issue as well.

Update: I have filed a bug with Apple (Problem ID: 4402288). If you have an ADC account (which is free) you might want to refer to that bug.

Update 2: The update to Mac OS X 10.4.4 and QuickTime 7.0.4 did NOT solve the problem. Damn.

Update 3: Apple has posted a tech support Article #302978: „PowerBook G4 (Double-Layer SD) audio stutters or skips“. For my part I can say that the problem occurs even when I am only running Ableton Live with no other applications running at the same time whatsoever. At least Apple has confirmed there is a problem and it actually seems to be tied to the 15″ PowerBook G4 only as expected. The document closes with „This document will be updated as more information becomes available“. Well, Apple, we keep an eye on that.

Update 4: So far I thought the problem is related to sound being sent to the built-in audio port only. But I recently encountered the audio loop problem in a setup where Ableton Live sent audio to QuickTime Broadcaster via the Soundflower virtual audio port. This seems to indicate the problem is related to software instead of hardware as the built-in audio port was not used in this setup. However, it might still be related to some kind of internal timing-related hardware.

Update 5: There is a new activist site dedicated to the problem at (or if you don’t like frames). If you have the same problem, you can add yourself to the list. The story has been dugg. Digg it!.

Update 6: is taking up on the story. Please let all other news sites know about this as well. The list of affected users on has grown to more than 800 now.

Update 7: is summarizing the disaster so far adding well-known display and DVD problems to the list. I haven’t had any of the display and DVD problems but I haven’t done so much DVD stuff recently as well so it might well be that more problems are ahead.

Update 8: According to a posting at Macintouch, an Apple employee at an Apple Store promised a solution to the problem „within a week“. We’ll see. Obviously the problem has received at least some attention at Apple.

Others have been reporting about the bug as well:

I know the Ableton tech support guy is suffering from the same problem.

So what is it all about?

This is what happens: Out of the blue, the Mac suddenly starts looping all the audio that goes out to an audio device. This usually last for around five seconds, effectively adding all audio being sent to that device playing everything over and over again at the same time increasing overall volume and creating a crazy and confusing mix that disappears after five seconds.

The bug seems to be related to CoreAudio as this is the subsystem managing audio devices. It does not seem to be tied to a certain application as I noticed the bug using iTunes, Ableton Live, QuickTime Player and other programs. There is no obvious event that triggers the bug, it just happens. Sometimes the event repeats within minutes two or three times and then again the bug is not coming at all for days. It is so annoying.

My configuration is the following:

  • Most recent Macintosh 15-inch PowerBook G4 (1440×960 display, optical audio)
  • Mac OS X 10.4.3
  • 2 GB RAM (I doubt the bug is related to RAM as the recent WLAN stability bug was)

Apple does not really promote a distinct name for the PowerBook generation introduced in October 2005 but I refer to it as the PowerBook with „Optical Digital Audio“ as it is the first Apple laptop to feature optical audio input and outputs. Read about it on Apple’s developer site. The most visible difference is of course the bigger screen size.

Main problem here is reproducing the problem. I haven’t found a way to do that so far and I am open for any suggestions. I think is related only to audio output as I haven’t experienced the bug when recording audio so the bug seems to not be affected to audio input. I only have been able to record the bug while producing audio feedback during the above session because I had loudspeakers running during the recording (as I did not have extra headphones for my guest).

So what can be done? I’d be happy if you would share your experiences with me here in this blog. I am going to reintegrate all feedback in this post to make the description as complete as possible.

27 Gedanken zu „Background information regarding the 15″ PowerBook G4 audio loop problem

  1. I do have sort of the same loop sound when iTunes is playing music and I am trying to burn a CD on my Mac mini. It’s just for 2-3 seconds and when it goes away the music normally continues and the CD burning starts…

    Since I did not have something similiar on Panther I would say it’s a Tiger related issue.

  2. Indeed this is soo Anoying! I just got the new powerbook 17 inch screen 2 gigg internal memmory 100 gig harddrive etc…

    And I have this same problem…

    Ive tryed various remeedes I found on the net or got from apples customer support (I think the people woorking there must be clowns of some sort).
    I tryed deleting the core sound prefferences (something like that) I did install some audio core thingy that did not work… I used some short comand that reset the sound… none of this works….

    I allso have found a way that provoked this to happen!
    It was playing some music in Itunes while your draging a heavy movie to Toast for burning on dvdr. Than it would happen more frekwently, as if the ram cant deal with the sound or something…

    Im getting really frustrated with this one! I allways had Apple computers and now is the first time I find they have such BIG problems. Planing to Work professionally with music on my mac, this makes me wonder if I Apple is such a good choice.

    Please someone! Some solution to this would be NICE! Is it a harware problem you think?

    I have found at least some twenty simmilar sites on the net talking about this sound loop / echo loop / echo sound problem on the mach and power books.

  3. Feel free to post links to other blog entries or articles on the web here to provide references for other people.

    Apple just released a OS X update that promises CoreAudio changes and a new version of QuickTime. Let’s see if this helps.


  4. I bought a powerbook in early november last year and am having this problem too. I’ve spoken to apple tech support who think it’s a hardware related problem because it happens in every sound app – itunes, quicktime plugin in safari etc. Considereing I use my pbook to produce with Logic 7, and want to use it to play music in live situations, this is not good!

  5. Add another reader to the echo chamber. System or hardware related, since it happens in all applications that have audio. Since I listen to music all day at work, it usually happens at least 5 times a day for me. In iTunes or in Firefox or Safari, listening to

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  8. Here is a forum dealing with the problem… Having read the whole thing, there is a guy who say he does not expirience the problems when using external soundcard, so Im starting to think it might be a hardware problem… I wonder if Apple will refund us or if they will TRY TO RIP OFF millions of people on all their savings.

    And this is the offical „explenation“ from apple saying we should only use ONE program at a time… If that was what I bought the stongest Machine/most expencive Apple Laptop on the Market for than I would have been better of with my old Imac that is 10 years old. That one could do many things simultaniously..

    Maybe Steve Jobbs is a wanker after all.

  9. An external sound device might be a workaround but has other significant problems: latency. Almost all sound interfaces I checked have had a significant latency mostly due to the bad Mac OS X CoreAudio FireWire device sound driver.

    The built-in sound device has the lowest latency. PC-Card based interfaces that might be in the same range are very expensive.

  10. Every single one of the latest generation 15″ and 17″ PowerBooks has this looping audio/echo problem. Every last one. If you send it in for repair, you’ll get one back that behaves the same exact way.

    Apple has done nothing about this major problem, except publish that misleading tech note. The note insults us all by not describing the extent and severity of the problem and further giving us the finger by providing a work around that not only doesn’t work around the problem but suggests we can’t use the machine for what it was designed and advertised to be used for.

    Contrary to Apple’s poor excuse, the audio echo/loop occurs even with NO applications running at all – the operating system’s own sound effects (like on emptying the trash can) are enough to trigger an echo fit.

    They’d better fix this f%@#ing problem fast, or they will regret it.

    So far, Apple appears to be ignoring us, with all their attention on the next generation Intel machines.

  11. Sorry to say We all do!
    Belive me when I say this.

    I have tried ALLOT of things to solve this issue.
    THEY are Obviously Choosing to IGNORE Us!

    They have to clarefy if its a Hardware or a Software issue!
    And then they have to give us a Emidiate soultuion!
    If it is a Hardware issue affecting all the New PowerBooks the Have to Make a RECALL (by law we have the right to claim this).

    If it is a Software issue (I doubt it though) Than they NEED to tell us this STRAIGHT AWAY and then they need to give us a DEADLINE for a FIRMWARE update ASP!!!

    Call apple and push them on the issue at hand. Ask them to read the Most rapidly growing Powerbook forum on the Net:
    And ask them what they are doing about it and WHEN we will have our Resolution. Dont hang up unless you feel you actually got some real facts and information. Allso make sure you get a case ID number.
    Next time you call them again on this matter you will just mention your number/case ID and this will save you allot of time explaining yourself.

    So please everyone we have had this Mailfunction for more than TWO Months now! Its Urgent that YOU CALL APPLE TODAY!
    I can not stress this hard enough.

  12. Add me to the list. I’ve filed a complaint. Totally brutal.

    I just added a gig of RAM (for other reasons, I knew it wouldn’t solve this issue). Incredibly, I think it’s actually made the problem worse.


  13. Marc,

    „insulting“ is really the best way to describe it. Especially considering that the Finder itself is (of course) using the audio subsystem as well just to playback the user interface sounds etc.

    I think Apple should be forced to acknowledge this bug as soon as possible.


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