Hi Sam,
What channels are you receiving? In your post to me you said only on the center and sub, in other posts you are saying L/R and sub.
If you are getting only center + sub I think you have a wiring problem. EDID problems wouldn't cause a source to only output those channels.
If it is L/R and sub are you sure it isn't just L/R and the sub coming from bass management in the Meridian?
Something to try....
Forget the MHR input for the moment.
1)Take the L/R SPDIF outputs on the Edge and plug it in to the Meridian configured for just a typical 2 channel input. Do you get sound?
2)Take the C/Sub output on the Edge and plug it in to the Meridian configured for just a typical 2 channel input. Do you get sound?
3)Take the L/R SIDE output on the Edge and plug it in to the Meridian configured for just a typical 2 channel input. Do you get sound?
4)Take the L/R REAR output on the Edge and plug it in to the Meridian configured for just a typical 2 channel input. Do you get sound?
If you are getting sound on multiple outputs (probably 1,2,3) the problem isn't the Edge.
Shawn