The new iMac has an important upgrade you might not know about. Apple's M3 iMac has an improved digital to audio converter and supports high-impedance headphones, which means it's an even better computer if you're serious about sound.
The iMac isn't the only Mac that supports high-impedance headphones. The 2021 MacBook Pro, the 2022 MacBook Air, the 2022 Mac Studio, the 2023 Mac Pro and the 2023 Mac mini do too.
The support document update, which was spotted by the eagle-eyed folks at MacRumors, explains that the iMac and other compatible Macs automatically detect the impedance of the headphones you connect and adjust the voltage accordingly. The two ranges are for headphones with an impedance of 150 ohms or less, and for headphones with 150 to 1,000 ohms.
If you're not familiar with impedance, higher impedance headphones require more power to drive them and, as a rule of thumb, deliver superior sound quality. It only applies to wired headphones; wireless headphones like the AirPods Max in our photo have their own built-in power source.
According to Apple "this may remove the need for an external headphone amplifier", although some music fans may disagree: the best headphone DACs and amps do more than just put out power.
The iMac's got a better DAC on its jack
In addition to the support for high power headphones, the iMac also has an improved DAC that works with digital audio at up to 96kHz (roughly twice that of CD quality but less than some hi-res audio), so you can connect analogue devices such s headphones or speakers directly to your Mac without necessarily needing an external DAC. You can set the sample rate in the Audio MIDI Utility, which lives in your Mac's Applications > Utilities folder.
Another useful thing about the iMac's jack, and of the other compatible Macs, is that the sensing also works for line-ins – so you can connect audio devices to the jack without necessarily needing a separate audio interface.
The upgrades are very much in the nice to have category rather than the must-have one, but as someone who uses relatively high impedance headphones with their Mac I can attest that you really can hear a difference. So it's nice that you don't necessarily need extra hardware to enjoy nicer headphones.