Pro logic2 will make any stereo source sound like 5.1.
DTS has the same thing basically.
Prologic music is the only "effect" you should think about using for music, all of the
"effects" (jazz, niteclub, etc) are notoriously bad, Yamahas are better than most, which means less bad.
As for the volume , there is something in the setup that allows you to change this.
There are basically two modes, one goes towards a reference level, which is why its a minus number that keeps decreasing.
The other setting is linear, goes from small number to a larger depending on where the vollume is set, most are more familar with this.
most modern receivers give you a choice of the two.
Before you hit the "reference" level you will probably go deaf, BTW.