Unstable audio volume in High Sierra 10.13.6

Apr 27, 2013
Gigabyte GA-Z87MX-D3H
GTX 1080
Classic Mac
Power Mac
Mobile Phone
After a few hours of work I have High Sierra up and running with everything working excelently except for audio (and imessage - I don't have an iPhone so I wouldn't be using it anyway).

The audio does work but whenever new audio plays it outputs at an extremely loud volume until adjusted with the volume slider.

E.g. Opening a YouTube video: when it starts the volume goes to max but the slider in macOS does not change. Adjusting the slider fixes the audio for the video until it is paused, where it returns to max upon resuming the video.

This happens across all programs including trying the sound effects in the audio options menu.

The same issue is present whether I use USB headphones or the 3.5mm output to my speakers.

If anyone has had this issue in the past and could point me in the right direction it would be much appreciated.

Otherwise I will try reinstalling the OS again tomorrow and see what I missed, as I am trying to make it as fully functional as I can with as few post install modifications as possible.


Sound is now working, although not in a way i fully understand at the moment.

It appears that macOS is seeing any connected USB device as though it is connected to a USB 3.0 bus.
If i connect any device to the rear USB 2.0 ports on my motherboard they appear in the System Information app to be connected via a usb 3.0 port.
This was leading my Headphones to be repeatedly "unplugged" every few seconds, messing with macOS sound settings and going to max volume when media source paused or changed.

However using a USB 2.0 hub i had laying around appears to let the headphones play nice as they now appear to be connected via the hub to a USB 3.0 bus.

Hopefully i can find a way to get this working properly again as i know this hardware is compatible since i have had USB properly working in the past.


Last edited: