Good news for new MacBook Air and Mac mini owners who are serious about audio. While yes, both machines retain the 3.5mm headphone jack, unlike some other devices Apple has recently announced, the new Macs now better handle audio when played through the jack or through the built-in speakers.
In a post on its blog, Rogue Amoeba explains that the 3.5mm audio jack and the built-in speakers on the new MacBook Air and Mac mini are now two separate devices in macOS.
Unlike before, this means that audio can be sent to both the built-in speakers and headphones at the same time. For example, with an app such as Audio Hijack, users can output audio from iTunes to headphones, while sending Spotify through the internal speakers.
A more practical scenario, however, is being able to send macOS’ system audio such as notification sounds through the built-in speakers, while having music playing through your headphones.
Read more at 9to5mac.com