Previous 1 2 Next 28 Replies Latest reply: Jan 25, 2013 12:56 PM by cheekypaul
octafish Level 1 Level 1 (25 points)

I've been trying to troubleshoot this problem for some time no on my Mac Pro. WIth just about any audio app - iTunes, Pandora, Ableton Live etc. after a certain amount of time, the audio starts to distort and ultimately gets reduced to a series of repeating clicks. I've switched up audio interfaces, switched up MIDI/USB cables. Tried plugging them into different ports, out of hubs and directly into my Mac. I thought it might be memory related, but it seems to happen when I have enough available memory as well. Happens in all audio apps. Any advice on how to troubleshoot?

Mac Pro Nehalem Octocore 2009, Mac OS X (10.6.6), 2x 2.26 Ghz, 12GB RAM
  • cheekypaul Level 2 Level 2 (210 points)

    does it happen with the audio interfaces (which ones??) only, or also with the headphone/audio out of the mac pro?

    are you sure the audio you are playing is good?

    do you hear clicks even when no 'music' is playing?

    how or when do they stop?

    can you record them in any software, say, ableton? or are they purely emanating from the speaker and not the file playback?

  • octafish Level 1 Level 1 (25 points)

    It has happened with multiple audio interfaces, including my brand new Focusrite Scarlett 2i4. I haven't tested it with the headphone jack on the Mac Pro, but I don't think that's the issue. It happens with audio from multiple apps, all high quality audio, that sounds great sometimes for hours at a time (I listen alot to Spotify, MOG and Pandora at the highest quality settings when I work), then all of a sudden grinds to a halt. It's software independent. Here's the error I see in the console when it happens:


    1/8/13 12:37:29.000 PM kernel[0]: IOAudioStream[0xffffff80421f6e00]::clipOutputSamples(0x3490, 0x200) - clipping function returned error: 0xe00002e7

    1/8/13 12:37:29.000 PM kernel[0]: stream sync error: input : 88601324 ( 48000)  output : 88602091 ( 48000)  (+767)

  • cheekypaul Level 2 Level 2 (210 points)

    sounds like you have audio drivers conflicting.

    when you say 'highest setting', what is it actually, when you get the crackles?

    i can see 48000 in your error. the audio you are listening to is very likely to be sent at 44100, the mac should resolve this but it may not be doing it right because of a conflict. it shouldn't be a problem, but sometimes these things happen.


    my m-audio firewire audio interface sometimes doesn't 'lock' and i get no sound, not locking may be giving you your clicks.


    open audio midi in the utilities. have a look at your interfaces' clock and format.

    make sure you are up to date and that your operating system is supported by the manufacturer of the interfaces you are using.


    screenshot 2013-01-17 at 14.40.59.jpg


    screenshot 2013-01-17 at 14.41.03.jpg

  • octafish Level 1 Level 1 (25 points)

    Mine looks the same as yours, but I have a few other sound drivers listed there. Soundflower and LogMein Soundriver. Maybe I can delete those and see if that helps?

  • cheekypaul Level 2 Level 2 (210 points)

    they should be fine sat there.

    the problem is when they are called into action, that's if i'm on the right track. but it could be something else and i'm barking up the wrong tree.


    the best way to solve these types of issues is to go through it methodically.


    where do you hear the crackles, ie where do they sound from?

    where ever they are coming from, get some headphones , intercept the signal , and find out if you can still hear the crackle.


    ps. do you play dvd's in your mac pro?

  • octafish Level 1 Level 1 (25 points)

    I removed the other drivers anyway (althogh I haven't restarted my machine yet) I don't play DVDs on the Mac Pro generally. It's not really crackles, the audio starts to deteriorate over the course of 5-10 seconds when it starts to go, distorts and degrades until all that's left is clicking. Sometimes it bypasses the clicking phase and just distorts and then stops entirely. I'm thinking it is some type of conflict somewhere, just a matter of identifying it. The problem is I can play audio for 8 hours straight without a problem sometimes before the issue arises again, so it's hard to troubleshoot.

  • cheekypaul Level 2 Level 2 (210 points)


    So, from where do you hear your audio?

  • octafish Level 1 Level 1 (25 points)

    From my KRK RP8 studio monitors that are plugged into my audio interface.

  • cheekypaul Level 2 Level 2 (210 points)

    Can you unplug your (unknown brand model and connection method) audio interface and instead plug your speakers to come directly from the Mac Pro?

  • cheekypaul Level 2 Level 2 (210 points)

    i'm not being facetious, i'm trying to ascertain where the problem originates.

    unplugging your interface and using the mac pro audio out and thus the apple core audio drivers, will help source the issue.

    either way, i hope you get to the bottom of it, sounds annoying...

  • octafish Level 1 Level 1 (25 points)

    I didn't mean to imply that you were being facetious. I appreciate your help. I've tried multiple audio interfaces and multiple USB cables, but not the Mac Pro audio out yet. I'll try that next. But if that resolves the issue, then I'm not sire what to do next...since I've pretty mych ruled out the audio interface, USB port and cable from being the issue already.......

  • cheekypaul Level 2 Level 2 (210 points)

    hi octafish

    you get the sound break up while audio interfaces are attached, so you cant rule them out as part of the problem.

    you've tried allsorts of cables and you still get the problem. using the mac without interfaces is the logical next step.

    let us know how you get on.

  • octafish Level 1 Level 1 (25 points)

    I'e been running audio out of the built in Mac Pro internal speakers all morning and have not experienced this problem yet. It seems like normally I would have by now, but I'll let it run until the end of the day to be sure. BUT, if I do conclude that this issue does not arise when running audio through the built-in speakers, what's my next step? I've tried different audio interfaces, cables and ports...are there any other variables I'm missing?

  • cheekypaul Level 2 Level 2 (210 points)

    great! that's something at least.

    it's very difficult resolve, it could be any number of things causing the problem. you just have to go through things one at a time.

    let us know what software you are using when it happens. is logic, quicktime, youtube. the moment you get the problem.

    i think it's something to do with the audio clock swapping from one state to another. like from 48k to 44k OR also quite likely, trying to run something without enough buffer.

    what kinds of audio software do you use?

    is this your gear? Mac Pro Nehalem Octocore 2009, Mac OS X (10.6.6), 2x 2.26 Ghz, 12GB RAM

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