ReadonlyauxNumber of AUX (monitor / FX) buses.
ReadonlydcaNumber of DCA control groups (control-domain coupling, carry no audio).
ReadonlyfxNumber of FX return buses — send/return delay/reverb, stereo.
ReadonlygroupNumber of sub-group / MIX buses.
ReadonlymainNumber of MAIN bus channels (e.g. 2 for stereo L/R, 3 for LCR, 1 for mono).
ReadonlymatrixNumber of MATRIX output buses.
ReadonlymixNumber of MIX-MINUS (N−1) buses.
A mix-minus is not a bus tier. It is MAIN − channelX — the main mix minus one
channel's contribution — so it has no per-channel sends (what makes it not an aux) and is
defined by one association: "this channel gets a mix-minus feed → this output", at the
per-destination route trim. It needs no fader and no bank slot; the bus is implicit in the
channel property. Nothing allocates one any more (presetBuses and
defaultAllocation both leave it 0).
The field itself is kept for now because removing it reaches well past the allocation — the console profiles' per-type maxima, the console-schema path budget, the session wire schema and the engine's existing mix-minus buses all still read it. It is retired with the channel-property work, not here.
The bus types a gig can allocate, one fixed count each. These are Roland O.H.R.C.A. path types:
auxandgroup/mixsub-buses,matrixoutputs,dcacontrol groups,mixMinus(the N−1 broadcast/IFB bus), andmain(LR / LCR / mono).