Oppo 105 Analog vs HDMI?


I listen entirely to classical music, and when I listen via the the Oppo 105's multi-channel analog outs (I use the main stereo LT/RT for the front channels), the sound is rather boxy/congested and has little depth. Via HDMI, the sound just blooms! The imaging is far wider, deeper, and the sound is simply more open sounding. I find this to be very puzzling since the analog section of the 105 is so highly touted. I do prefer the m-ch outs for solo instruments since there is less of a sense of depth in the first place. Any suggestions?

(Here is my system):

DALI Epicon 2 front speakers
Martin Logan Motif center speaker
Definitive Technology ProMonitor 1000 surrounds
Martin-Logan Abyss subwoofer
Sony 5400ES SACD
Oppo BDP 105 SACD/Blu-ray player
Marantz 8801 pre/pro
Parasound Halo A51 5-ch amp
128x128bachtoven
I'm not arguing with your hookup choice but I can't find any such suggestion in the manual for my Oppo 105. Can you point us to the page in the manual where it appears? I would certainly expect it (or any MCH-equipped player) to sound congested, the way you have it hooked up
It's on the bottom of page 74 in my edition--item number 7 in the Other Audio Processing section.
Why would you "certainly expect it (or any MCH-equipped player) to sound congested the way [I] have it hooked up"?
Why? Because you would be sending ALL the multichannel signals to the front left and right instead of just the ones recorded and INTENDED for the front left and right. If this isn't a recipe for congestion, I don't know what is.
I'll swap it back to the dedicated m-ch outs and see (or hear...) what happens. I don't know why the manual would recommend using the main stereo outs unless I wildly misinterpreted it!