Mixing And Routing; The Audio Bus Architecture - Steinberg HALION4 Mode D'emploi

The Audio Bus Architecture

The audio signals of zones, layers, programs, and slots are managed via audio busses.
The HALion slots always have one dedicated bus while programs can have one or
more audio busses that mix the audio signals from the layers and zones they contain.
Layers do not have to have an audio bus. However, you can optionally create audio
busses for layers at any time, for example to create a submix of the zones they contain.
You can load insert effects on any of these audio busses, for example to process the
audio of a single layer or a whole program. In addition, AUX busses allow you to use
send effects with zones, layers, programs, and slots. Send effects can be shared
between zones, layers, programs, and slots, which saves processing power. Zones do
not have an audio bus of their own. Instead, they have outputs that are routed
automatically to the next available audio bus. Any of the zones, audio busses, and AUX
busses can be assigned freely to one of the stereo outputs or the surround output of
the plug-in. For example, a zone output can be routed directly to an output bus,
omitting any audio busses and their effects in between.
The Default Audio Signal Flow
Typically, programs are loaded into a slot. Each slot is directly connected to an output
bus. The audio busses from the program send their signals to the audio bus of the
slot. A program can contain anything from a single zone to a couple of zones, or one or
more layers. Layers can contain other layers, which contain zones. The zones output is
mixed to the audio busses of the next higher level layers or directly to the program.
To save processing power, audio busses for layers and programs are optional. If a
layer has no audio bus, the zones in the layer are automatically routed to the next
higher audio bus.
Audio Busses
Audio busses can be compared to channels in a mixer but with much more flexibility
when it comes to mixing and routing possibilities. By definition, each slot has at least
one audio bus that mixes the audio signals from the layers and zones they contain.
Layers do not have an audio bus by default, but you can create audio busses for layers.
Apart from the routing and mixing possibilities, audio busses allow you to load insert
effects for processing audio on that bus. Depending on how you set up the audio
busses, you can load insert effects on single layers, the whole program or the slot. For
example, you can process only the strings of a piano and strings layer sound with a
chorus effect, and keep the piano unprocessed. You load insert effects into the effect
slots of the channels in the Mixer.
In addition, audio busses allow you to route audio via sends to an AUX bus. This way,
you can set up send effects, which can be shared among the layers, programs, and
slots. You assign sends directly in the zones or with the effect slots of the channels
displayed in the mixer. The sends have an adjustable level, allowing you to control the
amount of the effect that is loaded on the AUX bus.

Mixing and Routing

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