Weird popping sound coming from speakers connected to line out

[HumidSting]

So I've been using my cMP 5,1 for about half a year now, and love it. Got the OSXWifi up and running(mostly) and everything is purring like a dream.

However.

I have speakers plugged into the line out jack. And they sound fine, crystal clear, like if they were plugged into anything else. However, every once in a while, they'll make this "pop" sound. It's not too loud, but the volume is dependent on the volume dial of the speakers, not the system volume setting. Also, this doesn't happen if the speakers are plugged into a USB audio device. The speakers also do not make that sound if they're plugged into a different computer. I'm guessing it happens when I'm listening to stuff, but I can hear it best when nothing is being played out loud. Finally, this happened on another backplane, which I changed out once I bricked the EFI (which I now have found out you can fix with a MattCard).

Anyone have any ideas on why this would happen? The PSU is "new", bought when I first got the computer earlier this year.

Thanks!

 

[crjackson2134]

I don’t know the answer but mine does this too, and it has for a while now. I think it started with Sierra and so far continues through Mojave.

 

[goMac]

I've found all the cMPs noisy. USB hums, speaker pops. Maybe someone out there has a perfect one, but I've never had one that didn't make some sort of interference noise either internally or over speakers.