Small number of Pioneer AV receivers have issues with Apple TV Dolby Atmos support
The final arrival of Dolby Atmos support on the Apple TV and Apple TV 4K after a long delay may have been welcomed by AV enthusiasts, but there are a small number of complaints from users who are experiencing audio problems when using Apple's set-top box with their Pioneer equipment.
Posts on the Apple support forum as well as the AVS Forum claim the Pioneer Elite VSXLX503/US receiver is having issues playing movies from the Apple TV that use Dolby Atmos. While this specific receiver is capable of processing Dolby Atmos audio from other sources, it seems to be having issues dealing with sound using the same format stemming from the Apple TV.
An AppleInsider reader reports a similar issue for his Pioneer SX-LX58 receiver, noting the same lack of audio as well as the status on the receiver's display failing to show the usual Dolby Atmos status. While they have used a media center PC and can play Blu-ray discs with Dolby Atmos soundtracks without issue, the audio problem occurs just with the Apple TV
The reader and forum posters do note that there is a temporary workaround for the problem, in that Atmos has to be turned off on the Apple TV, forcing it to use a different format. Multiple users have made contact with Pioneer over the matter, with the AV equipment producer said to be working on a solution to the problem.
Apple's support page for Apple TV Dolby Atmos warns "some third-party AV receivers and sound bars might require a firmware update to support Dolby Atmos," advising users to visit their equipment manufacturer's website to check for new software.
Dolby Atmos is an alternative form of surround sound format that simulates sounds in 3D space instead of merely pushing them to different channels. Initially confirmed as being added to the Apple TV in September 2017, Apple revealed in WWDC 2018 it would arrive as part of tvOS 12, which shipped in September.