Audiobus(server,numchann)

Questions
36 
SynthDef(\myFx, { |bus, mix|
    var sig = In.ar(bus, 2);
    var wet = ... your fx processing...;
    ReplaceOut.ar(bus, XFade2.ar(sig, wet, mix * 2 - 1));
}).add;

I usually start with a template like this. All other options will be more complicated IMO.

hjh