John, no, not all DVD-As/SACDs have an LFE channel for high level bass effects. You see many of them with designations such as 4.0 or 5.0, and in that case the sub will have nothing to do if low bass from the speakers isn't directed to it. For example, I did get one 2 SACD set a couple of months ago even though none of my players do SACD, and it's hybrid with CD as well as 2.0 and 5.0 SACD
tracks(incidentally it's a
terrific bargain which I first suspected was a
pricing error and has all of the gorgeous music for Swan Lake).
I'm not familiar with the Joni Mitchell disc, but if you're certain that it's SACD, not DVD-A, then there's a bit of a mystery as to where the extra channels came from. SACDs don't have the DD/DTS tracks which a DVD-A has, and besides the SACD track(which has no output on a digital connection)if it's a "hybrid" it'll have a regular two-channel CD track. That would only give sound in multiple speakers if you applied DPLIIx to steer ambience from the two channels to them or used all channel stereo to duplicate the left and right fronts into the left and right surrounds(not likely, since you didn't mention it).
