Hmmm... maybe so. All 6 5.1 input indicators lit up on my receiver, but it could be the silenced center/lfe thing they do.
The four corners are sure active as hell, in a good way. IIRC, Tomita did some overdubs and stuff, so maybe there is something in the center? :couch
Sorry about that, but the only reason I asked was I could swear I saw them on a Japanese SACD site advertising as quad 4.0
or 4.1 ?
FWIW : My DVDA/SACD player disc info will show when I click on the remote either 3/2/1 or for most quads 2/2 and sometimes 3/2 .(silent centre though).