Sony ES owners; A.F.D. Auto soundfield question (1 Viewer)

[bikerxl]

I got a Sony STR DH 720 with Sony Internet TV & Blu-ray Disc™ Player Powered by Google TV box connected with HDMI. like shown here
http://esupport.sony.com/docs/btv-manuals/flyers/Flyer_AVReceiver_connection/4270510112/img/4270510112_01.jpg
Just bought and installed Polk audio in wall speakers in a 7.1 set up.
I had the STR in AFD mode but was not happy with the sound quality and it would not transmit in 7.1 but rather 5.1 when playing bluray disc with 7.1 audio like Transformers Revenge of the Fallen.
I tried all different settings on the STR720 but no luck, so I tried optical cable with no better results.
So I started messing with the blu ray player audio setting and one audio setting fixed my problem.
It was the BD audio mix setting, it was turned on by default, as soon as I turned it off and start playing the bluray with AFD auto setting on the reciever the surround system switched to True HD audio 7.1
Thought I'd share this in case anybody else has similar problem.

 

[ptuk33]

Thanks @walkoffhomerun for that really clear explanation. However, I'm having a similar problem with my Sony STR-DH510 receiver: I simply cannot select any sound field other than A.F.D. Auto. The problem seems to be that the device I'm outputting from (a Mac Mini computer), provides a Linear PCM output. In the STR-DH510 manual it says "When multi channel Linear PCM signals are received via an HDMI IN jack, 'A.F.D. AUTO' will be selected automatically." In other words, I cannot use the receiver to play a stereo recording through a Multi-St sound field because the receiver simply won't let me choose Multi-St, and nor will the audio output settings on the Mac. Any ideas here? I'd be hugely grateful!

 

[ptuk33]

OK, I've solved the problem by using Apple's "Audio Midi Setup" application to force it to output stereo audio at 48k Hz. This prevents the receiver from treating the input as Linear PCM (can that be right?) and enables me to use its Dolby Prologic to distribute the sound across all five speakers. I'm very happy at the workaround, but still utterly confused as to how it has worked...