In short the SPDIF connection from the DVDO will be nothing like that of an MHR connection. There is a physical hardware limitation in providing multichannel high resolution audio to multiple channels over one coaxial connection. This is why Meridian uses the 3 connections for MHR multichannel use.

There is also a decoder in the HD621 that maintains copy protection for the MHR source taken from the HDMI signal. Meridian is one (maybe the only) company who can legally do this. Most equipment have to use the HDMI connection with HDCP to get any sort of high resolution multichannel audio.

Any signal from the coaxial output of your DVDO will be of the same variety as that of the digital coaxial output of the Oppo. That source will be compressed. Some think that the DTS core signal (availably by a single digital coaxial signal) at 1.5Mbit/sec is audibly identical to it's DTSMA uncompressed brother. So you may get decent audio this way.

On another controversial note I would imagine the Oppo would have better audio quality than the DVDO due to it's superior processing abilities. I hope this helps.

Nick

558.2 amp, Meridian A500 speakers, M2500 sub, Director & Explorer DACs