I'm somewhat confused by what you mean as far as the downmix goes. Do you mean that "downmix" is when the Oppo downmixes the full DTS-MA to a 1.5Mbit DTS through the coax output? Or are you saying that downmix is when the Oppo decodes DTS-MA and then downmixes to 2-channel analog output (by means of dolby pro logic)?
The 5.1/7.1 downmix of DTS HD MA or DTS True HD soundtracks is much better for 2ch stereo analog output with the BD-83 and better still with the BD-83/NE, than the BD-09. I don't think this downmix of the Oppo has much to do with Dolby pro logic, unless you pre has that option. imo there is no need for any enhancements like Dolby pro logic.
Second question. It is apparent that the analog L/R of the dedicated stereo output is much better then the analog L/R of the multi-channel output from the BD-83SE because of the 2-channel ESS DAC and the better analog output stage. What we all would probably like to know is how the multi-channel outputs of the BD-83SE/NF compare with the Pioneer 09FD. Many people have said that BD movie audio is generally not that great when compared to music, and I would generally agree with this. However, there are some movies which do have extraordinary audio. An example of this would be the intro music/female voice from We Are Marshall. Of course the music is sent to L/R and the voice is sent to center. I'm sure there are other BD movie examples that could be used as reference audio (this would be like comparing the output of jazz versus hard rock on a high-end 2 channel system -- it's all about the audio source style -- some music sources come across much better).
As far as BD movies not sounding great in 2ch dedicated stereo mode of the BD-83NE, that is imo not true at all. Of course it all depends on how good the soundtrack is master, just like a CD/SACD. So I will now talk about just my BD-83NE and my audio system. The L/R RCA dedicated 2ch stereo downmix is wonderful. The audio is very 3 dimensional, very dynamic, very fast, excellent high to low range and tonal quality, also the ability to pickup the the back ground sound effects. ( I am talking about BD movies).
You indicated that the "BD-09 was better for AQ for 2ch analog than the BD-83". However, you also said that "the NE beats my BD-09 for CDs". Are you indicating that the Pioneer had better audio for BD movies when doing pure 5.1 channel output and not downmixing the audio?
No not at all, read above.
The BD-09 is a superior in build quality to the BD-83, and also the BD-09 has a better power supply and the BD-09 has a better platform/design build than the BD-83. Plus the BD-09 is rock solid as a BD player for video/audio. But that's where the pluses end.
With the design of the audio board and the mod of Nuforce and not so much but still very well planed BD-83SE, the shot comings of the build quality with the BD-83SE/NE are all over come and then some. imo the firmware of the BD-83/SE/NE is far superior with the BD-83 than it is with the BD-09.
I am at an impass as to the best direction to take (as I'm sure many others are). If the BD-83SE/NF is comparable to the 09FD, then we may have a great platform to work with (especially after a Modwright mod). However, if the 09FD is still the superior BD movie platform, then maybe that is the direction. $2k for the Pioneer, $2.2k for the BD-83SE plus Modwright makes both of these options similar. When you look at it this way, the real base difference is the DACS. Single-chip ESS dac for 7.1 on the BD-83SE and 8 dedicated Wolfson DACS in dual mode on the Pioneer.
That is a pickle that is for sure.
On paper the BD-09 should be a better 7.1 analog player than the BD-83SE. Of course you are asking about a Modwright full mod. I am sure Dan does a very good job with his mods, and if Oppo/Nuforce didn't come out with the BD-83NE I think i may have gone the Modwright way. But $2,200 is a lot to spend for a $900 BD player, and then there is the problem of warranty. That said, I would hope if you go the Modwright way you would have a world class player.
As far as the BD-09 I am sure I will not be using it anymore, because of my BD-83NE. And at this point I have no interest in doing any mods to my BD-83NE.
Now for the 7.1 MC question. I don't use the 7.1 MC outs. The reason is I only have a Onkyo TX-SR705A/V along with a 7.1 sound speaker system. imo this is not audiophile grade equipment, so for me a audiophile grade BD_83SE modwright or for that matter a BD-83NE would be over kill and somewhat of a disappointment.
On the other hand my 2ch analog gear is audiophile grade and the BD-83NE really shines in that configuration.
So you may be just as well off with a BD-09 for less money then the BD-83 full mod by Dan if you have a run of the mill 7.1 system as I do. Plus the BD-09 has 2 HDMI out ports, one for video and one audio. However the downside for the BD-09 is it can't play SACD,DVD-A where the BD-83 can but is buggie as I just found out.