iTunes 5.1 surround playback now works without decoder

[reichman]

Finishing up work, I happened to click on an iTunes movie trailer and was disoriented hearing iTunes 12.7.0 play 5.1 content through CoreAudio to my 5.1 studio system. Previous versions of iTunes only played stereo content in macOS. They required an optical output with an AC-3 decoder. No longer. Does anyone have more info about this unannounced change?

[Big World]

Very cool! Works for me too. Thanks for the heads up!

[JR Fountain]

Just tried updating to iTunes 12.7.3 and it still plays stereo here. Any idea why you guys are able to get 5.1?

I'm running 10.10.5 on 5,1 mac, Avid OMNI, PT Native HD

Thanks!
JR

[BScout]

Do you have a surround speaker configuration setup in Audio Midi Setup? (Computer sounds selected device, speaker configuration, multichannel setup)
It will down mix if it has only stereo setup from there.

Is your Omni your output device?

[JR Fountain]

Yes using the Omni as the output device.

In Audio Midi Setup I clicked on "configure speakers" and setup the multichannel output with corresponding speaker outputs and tested and that was fine. Closed Audio Midi Setup, re-opened iTunes but movie still played back in stereo.

HD Native is selected as the output device in my Sound preferences of the OS.

Any other suggestions?

Thx!
JR

[reichman]

FWIW, I'm listening on my home rig with macOS High Sierra and an Mbox Pro 3 connected in 5.1. In theory, any Core Audio connection should be the same.

JR Fountain, not all content in the iTunes store plays this way. I noticed some of my older TV shows that were mixed in surround don't play in surround unless decoded. Content that is playing back in undecoded 5.1 includes La La Land, Blade Runner 2049. And the Big Little Lies episode previews are playing in 5.1. Outlander episode previews are not.

[spoons]

Thanks for this. Works perfectly as instructed through my Scarlett 18i playing Rogue One.

[JR Fountain]

Hmmm...still not working for me. Tried the Big Little Lies previews and they're still playing stereo. I tested my Audio Midi Setup by changing the speaker outputs in the 5.1 configuration to see if they followed, and they did. So it seems I'm just not getting a 5.1 signal from iTunes. I wonder if it's OS related being on Yosemite?

JR

[reichman]

I wonder if it's OS related being on Yosemite?

That's the only thing I can think of. Apple does make changes to audio under the hood (from reading tech docs I see that some audio-over-IP have been reliant on Apple OS architecture).