iMac Pro Imac Pro Sound Glitches

Discussion in 'iMac' started by majestice, Jun 4, 2018.

  1. majestice macrumors member

    Oct 16, 2015
    Since day one my iMac Pro has had weird sound glitches where the sound breaks down as if it was recorded on too high volume (the volume level doesn't change), basically the sound is like it is going through distortion filter in a same sense you could compare the sound of acoustic guitar to distorted electric guitar. It doesn't matter if it is external speakers or the internal, it happens the same. It will stay like this until change from external output to internal or vice versa depending which one you had on when the problem occurred and I remember few times you had to switch it back and forth few times before the problem went away.

    After upgrading OSX the phenomenon became rarer and while it sometimes still breaks (and stays broken until the output switch), now I hear loud "cracks" popping every now and then but the sound returns to normal after that. The "cracking" sound is bit like if someone moved the audio jack in and out when the speakers are on.

    Since the error appears on both internal and external speakers I think we can rule out faulty cable or even faulty connector on computer. This has to be some sort of sound chip or software problem. Has anyone else run into this? If yes how did you solve? I can't reproduce the error and sometimes it happens often, sometimes it can take long time for it to happen again.
  2. NajamQ macrumors member

    Apr 30, 2018
    Type "Audio Midi Setup" in spotlight and run the utility. (You can also open it from utilities folder in Applications).

    Check what's the format your Mac is using. (Take a screenshot for reference). Then try 48000Hz for built in speakers (output). Experiment with different bitrates to see if it helps.

    These crackling, clipping, static pops usually happen on mac if you are using some audio utility e.g. Boom2 or some software is running it's helper in background which is not compatible with audio kext.
  3. majestice thread starter macrumors member

    Oct 16, 2015
    Thank you for the input. Tried it but unfortunately this method didn't solve the issue... :/
    Programs usually running are Premiere or FCPX but seems like it happens even when these are not open. The setup is restored from my iMac backup exactly it was before, all the programs are the same. Only thing that changed is OSX version (iMac was running El Capitan) and hardware of course. I had no problems like this ever on my iMac late-2015 (lots of image retention though even after changing the panel, so it wasn't happy marriage either)
  4. NajamQ macrumors member

    Apr 30, 2018
    You may have to reinstall MacOS from scratch. Do you have a TimeMachine backup?

    Also by restoring you mean you had a backup from your old iMac and restored the image to your Mac Pro? Did you copy only data or omplete restore from backup?

    Image retention is a giant, it will follow you wherever you go with retina iMac.
  5. majestice thread starter macrumors member

    Oct 16, 2015
    Restored from full iMac time machines backup to iMac Pro
  6. NajamQ, Jun 11, 2018
    Last edited: Jun 11, 2018

    NajamQ macrumors member

    Apr 30, 2018
    Then it's worth doing the experiment. Make a last minute backup to Time Machine and install a fresh copy of MacOS after erasing the drive. Then use the iMac Pro for a day to see if you still get same problems. If your problems are solved, then restore from TimeMachine but only your data, not Library or user Library folder files.

    You will lose some settings or files but you can manually copy those from relevant location folder in Time Machine drive.

    PS: You can use macOS Recovery to use Disk Utility, it will download macOS for you if you have fast enough internet. Otherwise manually download from AppStore and prepare a USB beforehand.

    To create a bootable USB: (Preparing the USB takes a lot of time, around 25-35 minutes so don't panic)
  7. odinbar macrumors newbie

    Jul 20, 2018
    I thought that only I have such a problem,
    I have imac pro also , and I have very similar symptoms ( loud "cracks" popping every now and then but the sound returns to normal after that. The "cracking" sound is bit like if someone moved the audio jack in and out when the speakers are on.)

    Have you solved the problem?
    did you connect to imac external monitors ?
    have you tried contact apple support ?
    problem , as you correctly wrote, reproduce the error , sometimes it happens often, sometimes it can take long time.
    I think too that this is a software problem
  8. Sirup Guy macrumors newbie

    Jul 23, 2018

    I'm sitting in the same boat. Standard iMac Pro (IMAC PRO 27"/3.2 8C/VG56/32GB), did a clean install.

    Not always reproducible. But had sound glitches for example by running Spotify while compiling an app that register sounds in Android Studio.
  9. BeatCrazy macrumors 68000

    Jul 20, 2011
    This bug happened to mine yesterday. A reboot seems to have solved the issue.
  10. majestice thread starter macrumors member

    Oct 16, 2015
    You don't need to reboot, just change the output between internal and external. The glitch happens in the "soundcard" and it happens regardless of which output you have on. Anyways this is not solution to the problem which Apple should fix.

    I think it is a problem with the T2 co-processor as it was reported to have some problems and it is also responsible for sound. Now lots of Macbook Pro users are reporting similar problems (that being a computer that has more consumers buying)... it also has T2 co-processor. Glitches on my computer can't be reproduced, at least I can't figure out a pattern how to create them but it happens while doing different things from using premiere to watching movies with VLC, watching youtube or listening spotify.. all of these have cause the problem to occur
  11. Stairway macrumors newbie

    Aug 6, 2010
    So are folks reporting this problem only with the internal sound --- i.e. does the problem go away if you are using an external audio interface (such as a UAD Apollo)?
  12. Trebuin macrumors 65816


    Jun 3, 2008
    Central Cali
    100% audio quality for me, external speakers only.
    I do experience audio crashes when I switch from external speakers & AirPods
  13. Anigart macrumors newbie

    Aug 18, 2018
    Same issue here. I noticed that it happens much more often when running Windows (either in a VM, or through Bootcamp). Playing certain games, this is highly reproducible, but it can happen with other apps too. Other than crackling sound I also get echos. A restart of the app in question usually fixes it, so this is a software issue.
  14. bscotchcummerbunds macrumors newbie

    Aug 23, 2018
    I have been experiencing the same problem for a month or so now as well. iMac Pro - running 10.13.6, 10 core, 64GB ram, 1TB SSD, 8GB graphics card. I also cannot force the issue to reproduce on demand, I think it just happens after a certain amount of time while actively using the UI.

    Here's a link to video of what's going on with my distorted audio and the system preferences trick to resolve it temporarily. I've pixelated the screen a lot, but you can still get the idea.

    Yes, the music is heavy metal but it also happened when I was listening to The Greatest Showman soundtrack and Big Boi.

    Things I've tested: NVRAM resets, SMC resets. An external usb audio interface or displayport interface works fine, no distortion ever. I tried both through a display and an M-Audio usb 2.0 interface.

    I've checked and I have no new or abnormal loaded extensions (no soundflower or anything like that).

    3.5mm output distorts in my main user after anywhere from 30+ minutes of use from any audio application with both powered speakers and headphones - verified distortion in Spotify, FCP X, and iTunes. Weird part is it doesn't happen while the display is asleep. I've left music playing overnight in both a separate admin account and my own user in both iTunes and quicktime player on loop and recorded the output with a zoom handheld recorder 3 separate evenings, and recorded no distortion over the course of the night, though it stopped playing music after 4-6 hours on it's own despite being only set to display sleep, not computer sleep. I'm going to repeat the test tonight with a looping automator action of 10 hours of Watch Me Do clicking the mouse on the desktop in a couple spots to simulate UI activity.

    The REALLY crazy part is that yes swapping interfaces (from headphones to internal speakers) fixes the distortion issues temporarily, but even just playing UI sounds will resolve it too. I tested by waiting for distortion to happen, opened system preferences to the sound effects panel and clicked Glass (set to play sound effects through the same interface as regular output) and then sound returned to normal for a while until the distortion creeped in again. Similarly, when I sampled the coreaudiod process in Activity Monitor, it also instantly cleared up the audio like the sys prefs trick. I don't know if it's interrupting the process somehow and resetting whatever is going wrong, but from what I can tell its not the 3.5mm jack which is part of the rear housing, but definitely OS/user account related.

    I haven't been able to test in another user full time while using the UI, since I use this machine for work every day and it's a crazy time of year right now and don't have the day to setup all my processes in another user. I have time machine and bootable backups but haven't gone through that yet because again, busy time of year, and I can just use the USB interface for the time being.

    I'll reinstall the latest combo update during lunch today and see if that makes a difference.
  15. MORZA macrumors newbie

    Nov 13, 2009
    I've had similar issues with audio on my iMac Pro 10 Core, 3 GHz Intel Xeon W, 32 GB 2666 MHz DDR4, Radeon Pro Vega 64 16368 MB since day 1.

    It's really annoying but intermittent. Usually happens when I'm working in Premiere or After Effects. I've been too busy to take it in but this really needs to be fixed.
  16. Aftershok macrumors newbie

    Sep 29, 2011
    Los Angeles
    Count me among the afflicted, and it seems to be happening more often each day. Switching out outputs in System Preferences cures the issue, but only for a couple minutes. Sometimes switching between apps clears it up briefly. ...but it always returns. Making me nuts. :(
  17. tjdalyvideo macrumors newbie

    Aug 27, 2018
    Oh no! Me too. Stock iMac Pro, exact random audio glitches from 3.5mm jack regardless of application, speakers / headphones. Mostly hear it in Premiere or Spotify.
  18. Peter_M macrumors member

    Jun 20, 2018
    My iMac Pro will sometimes crash, ie. the sound is stuck on a short repeat (like a stuck CD), and any program using sound freezes/crash. I have to reboot to fix the issue. This is with internal speakers.
  19. tsrail macrumors newbie

    Nov 21, 2011
    Me too. often on system sounds (alerts). Sometimes on random and intermittent distortions. Pretty stock software, generally. FCP X and Logic Pro X are installed, as well as Airfoil (although it is never running when this happens). Other apps include Adobe CC, GoPro, Audacity. when youtube does it through safari, it usually works if I close safari and reopen.
  20. spheris macrumors newbie


    Aug 8, 2018
    The American Empire
    The T2 is a tricky bastard. It's been firmware patched twice now for the MacBook Pro for high Sierra and I'm a little concerned that it hasn't been for the iMac Pro so far. The community might have to exert some pressure on apple to get them on it - if it hasn't been addressed in Mojave. Just as a side note, there was a substantial firmware update in DP7 for Mojave that some people reported fixed the kernel faults. So it might fix itself with the next update cycle.
  21. TkthiagoX macrumors newbie


    Sep 6, 2018
    same problem here!

    i use iMac Pro
    xeon 18 core
    Radeon Pro 64 16368 MB
  22. MrBombasztiek macrumors newbie


    Dec 12, 2017
    I have the same problem on my 10 core iMac Pro. Any suggestions how we can apply collective pressure on Apple to fix this?
  23. Scary Spice macrumors regular

    Scary Spice

    Jul 31, 2015
    British Columbia
    Nothing amiss on my iMac Pro 10 Core, 3 GHz Intel Xeon W, 32 GB 2666 MHz DDR4, Radeon Pro Vega 64, 2TB SSD.

    Sound is glitch free on every sound output. Rocking the 'Blow' alert sound like no other!
  24. ozne macrumors newbie

    Sep 9, 2018
    Same problem here. iMac Pro 8-core baseline model.
  25. Peter_M macrumors member

    Jun 20, 2018
    I just sent a new bug report to Apple, with three different sysreports (from three different crashes). Hopefully Apple can figure this out soon.

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