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Over the last week the sound of my external speakers have slowly decreased and are now to the point where they are max out in the OS but and yet you can have to strain to hear them.

What I have done thus far.

  • Checked System Preferences -> Sound -> Output -> Both Headphones and Line Out are maxed and are NOT muted
  • Checked Utilities -> Audio MIDI Setup -> Built-in Line Output (M) is all the way to left (1) is all the way to the right (2) is all the way to the right. When I click on configure speakers. Stereo is selected then when I click on left or right speakers its not that loud.
  • I created a new user on the system and tested the sound on the new user. This doesn't fix the sound at all.
  • I have gone into System -> Library -> Preferences -> and removed the audio folder and the two files in the folder
  • I have rebooted the system and held down Command + Option + P + R to reset the PRAM (had the system reboot 3 times the first test and 7 times the second test
  • I have opened the Mac Pro and removed the battery off the motherboard and waited 10 min while the machine was unplugged. Then placed the battery back on the motherboard and powered the machine back on.
  • Plugged in 3 other sets of speakers and they are all the same, including 1 headset.

Anyone have any other ideas on how to fix this sound problem?

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Have you had your hearing checked? Regards. – Xavierjazz Feb 26 '10 at 21:24

Have you tried using another output device, such as USB out or your internal speakers? Do they also have this issue?

Sounds like that specific output device is losing its connection, perhaps from the soldering breaking or maybe dirt in the port. Take a Q-Tip or compressed air to it?

Perhaps some fun software got installed that's having fun with your kernel extensions. Does safe boot (hold down shift at boot) help any? Does the sound do better while booted off another OS (or your system disk)? An archive/install might fix it if it's not hardware-based.

Might be time to pull out the warranty papers!

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The internal speakers work just fine. As for the output jacks, it doesn't make a difference in volume if I use the front or back jack and I have cleaned both. – user29570 Feb 26 '10 at 23:41
Do you have the system volume feedback enabled (clicks when you change volume)? If so, compare the sound from it booted on your normal system and try booting off system disk and see how it compares there. – Nerdling Feb 27 '10 at 7:35

Make sure that you have installed the latest MacPro Audio Firmware Update; Apple released an update specifically to deal with sound issues on the MacPro.

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This update is for a different model of MacPro. I have also checked for other updates and couldn't find any for the version I have. – user29570 Mar 1 '10 at 18:12

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