Mac mini audio bleed

I have the same problem only I'm using a MacBook Pro M1 Max 64Gb 2TB model 16inch 2021 model. But for now the problem seems to be gone... See below.

I too make backing tracks using Pro Tools. I believe this to be a software issue... not with Pro Tools but with the Mac OS. I've done backing tracks for two years now, for a pro band, using this machine and only recently noticed this stereo bleed over problem.

For the apple people who might read this.. having that click track spill over into the other channel is a disaster, since the click track is panned hard left or right while the musical part is panned hard the opposite way and sent to the FOH (front of house) system. So while the drummer hears the click track, you definitely DON't want that click being sent to the FOH channel for the audience to hear!

This bleed through is very low and in regular mixing would probably not be noticed expect in cases where one channel needs to be completely silent while the other plays (which is almost never).

Here's what I've done:

I contacted the Pro Tools support folks and done all sorts of tests. I created a mono track and using the tone generator put some audio on the track.

I panned the track hard 100% left but could still hear it bleed through to the right channel. I repeated the test with everything panned hard right and I could hear bleed through to the left channel.

Thinking It might be something in Pro Tools panning, rather than "pan" the track I changed the output to "Output 1", which in Pro Tools is the left channel. I could still hear the bleed over on the right.

I routed the output through each my Focusrite audio interface thinking it might be a problem with the interface. Then I disconnected the interfaces and routed the audio out through the MacBook speakers and then through the headphone out jack. I could/can still hear the bleed over.

So I bounced the audio out of ProTools to an MP3 and played it back using Quicktime, first through the audio interfaces, then through the Mac's speakers, then through the headphone jack.

This is where it get's interesting...

Using the Mac "Sound" panel balance control on the output tab I moved the slider back and forth while playing the MP3 file I created (remember the file was created with everything in the left channel}. Set dead center I could hear the bleed over, slid all the way to the left I could still hear the bleed over, but when I slid it all the way to the right the bleed got progressively quieter and I couldn't hear it at all when I had it completely over to the right. At first this didn't make any sense, but then all the audio on the MP3 is in the left channel. So but then all of the audio is present ONLY in the left channel of the MP3 so moving the slider completely to the right it would naturally diminish. But It remained present, in the right channel, until the control was slid ALL the way to the right.

I tested the file on my iPhone and iPad as well. NO bleed over!

I ended up completely reinstalling the Mac OS. I tested it with a fresh OS installed using the internal speaker and headphone outputs without ANY other software loaded. The problem persisted.

With the help of the Pro Tools people I linked to this forum the the following two links.

https://support.apple.com/en-us/HT202731

https://support.apple.com/en-us/HT203747

I followed the instructions in the first link to run diagnostics on my machine. It reported NO ISSUES. Except the stereo bleed issue is now GONE. I don't know how or why. But it's gone at least for now.

I know that's a long explanation just to get an answer (maybe it's not a permanent solution). But it's there for the apple people to consider.

I should note that the ProTools people were listening to the MP3. I sent them on a Mac mini. They did not experience any bleed over the links that I posted that have instructions on how to run the diagnostics. Have one set for M1 based Macs and one for Intel based Macs. I think the issue may be related to or triggered by audio routing software, such as Gig performer, or Loopback, since I did not experience any bleed over until I had installed these two applications on my Mac.

well if it's a hardware issue rather than a software issue then by definition only a hardware replacement can resolve the issue.

What headphones and how are they connected to the Mac mini?

Is the headphone jack firmly seated in the output port?

Have you tested a USB to audio adapter?

What Audio software are you using?

Thanks my friend, have sen a few inexplicable cures, hope this works for others.:)