If you want to use your Apple TV for audio with your TV switched off then this post is for you. First off you will need to invest in an optical cable (and possibly an optical to RCA adapter). Once you have your Apple TV connected to an amp and speakers then your should be able to Air Play from an iOS device connected to the same wireless network or start Music from your Apple TV and then switch the screen off.
I’ve checked this with a number of Samsung screens as they do not affect attempt to block the use of the HDMI port. Unfortunately I do not have other TV’s to be able to test this but have found this article which suggests that LG screens should work too. If you struggle with running your Apple TV headless then you might want to try with another display switched off to see if this is the issue.
If at first you are having problems hearing your audio then you should check the Apple TV settings to ensure that Dolby Digital is switched off. You may also find this of use if you are trying to play content from services such as Netflix which is stereo only.
If you are running Apple TV headless for audio or having problems, then please get in touch to let us know.