The 3.5 mm headphone jack on the MacBook Pro (14-inch, 2021) or MacBook Pro (16-inch, 2021) features DC load detection and adaptive voltage output. In the document published October 27th 2021 and titled Use high-impedance headphones with new MacBook Pro models Apple explains Apple has released a support document explaining in detail the technology behind the high impedance headphone output on the new MacBook Pro using the new Apple Silicon powered M1 Pro and M1 Max chips.
