M1 Pro MacBook Pro sound output problems

Is it just me…or do regular earphones with the phono plug not work automatically with the new laptops through a phono to USB C adapter? I had one of those already for using the earphones on my USB C iPad Air and they work fine there but on the laptop the audio stays on the speakers when I plug the USB C connector in…and it would be simpler not to have to pull the adapter off or change the output in Control Center.

I think you’ll have to select the output device via System Settings or Control Center.

Macs (unlike iPads) can have many different audio output devices (built-in speakers, HDMI, Thunderbolt, USB, etc.) It doesn’t (and shouldn’t) assume that one overrides all others, because you may want them all active at once (e.g. output from different sources).

This is actually nothing new. On my Mac mini, the built-in headphone jack doesn’t override the built-in speaker. I needed to explicitly select it for my default audio output (it is in-turn connected to my speakers) and I can choose to use the built-in speakers at the same time for some apps, if I choose to do so.

And I think this is the way it should be. Consider, for example, a speaker built-in to a USB speaker-phone device. You probably want to use that device for conferencing (FaceTime, Zoom, etc.) and probably not for anything else.

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You’re probably right…although just plugging in the phono plug to the jack does switch the output…and the laptop recognizes the USB C adapted earbuds when they’re plugged in since they become an option in Control Center…but I would have guessed tht plugging in earbuds would switch the audio output regardless of the connection method. I would have AirPods which get round the issue and auto switch like my bride has…but too many years in submarine engine rooms and getting older means I’ve got hearing aids…mine are Resound and work fine but they’re paired to my iPhone and switching them to either my iPad or laptop is a multi step evolution so I use the earbuds for both of those…and it’s strange that the USB C adapted one’s work as expected on my iPad Air 4 but don’t work as expected on the laptop. Guess I will either pull the dapper or use CC.

It’s not just you. I have a very similar problem. I also bought a USB-C to 3.5mm adapter for my external speakers. If I plug them into the Audio jack on the MBP, they work fine. When I plug them into the adapter, and then into my hub (my end goal: one less cable plugged into the MBP), I get a constant hum on the speakers, but no indication of a selectable output audio source in System Preferences > Sound. To eliminate the hub as the problem, I plugged the adapter directly into one of the MPB’s USB-C ports. Same result. In my pre-post “let’s be sure I’m not overlooking something obvious” scan, I see that Apple actually sells an adapter for seemingly this very purpose. Should I now suspect the adapter (non-Apple) is bad?

The mini is the odd one out. My 2015 mini also did that. But every other Mac I’ve owned turns off the speakers as soon as you plug in an audio-out device. As early as boot time in fact. Again, the Mac mini surprisingly did not do that. Haven’t tested it yet on my 14" MBP though. Maybe Apple decided to change things. Not that I’d have wanted that.