So based on Bigtee response, you only get extended resolution audio if sent via analog not via the HDMI as the HDMI does not have the capacity to carry both an HD video signal and a HD audio signal together.
So, the use of the 5.1 analog outputs will give you the best results for audio, unless you can output the HD audio digitally to a good pre/pro (presumably with better DACs than the Sony).
If you are taking the HDMI signal to your pre/pro, are you programming the pre/pro for video only from the HDMI or audio as well? I would not suggest using the HDMI for audio.
Personally, I would suggest taking the audio signal output separately from the HDMI cable for best audio results. Typically, a good pre/pro will perform best receiving the audio signal in a digital format as it will usually have better chips than the DVD player. Of course this depends on the player and the pre/pro.
So, the use of the 5.1 analog outputs will give you the best results for audio, unless you can output the HD audio digitally to a good pre/pro (presumably with better DACs than the Sony).
If you are taking the HDMI signal to your pre/pro, are you programming the pre/pro for video only from the HDMI or audio as well? I would not suggest using the HDMI for audio.
Personally, I would suggest taking the audio signal output separately from the HDMI cable for best audio results. Typically, a good pre/pro will perform best receiving the audio signal in a digital format as it will usually have better chips than the DVD player. Of course this depends on the player and the pre/pro.