Installation guide

The following table lists the parameter values for both the current system and for the preset:
Gain parameter Off @ Min parameter Mute parameter
Current Working Values -35.2 dB Selected Deselected
Lobby Preset -6.5 dB Selected Deselected
When you apply the preset, all of the preset's LobbyVolume block parameters become the current working
values. But only one of those parameters has a different value (the Gain parameter) and is, therefore, the only
system parameter that will actually change.
Now let's assume the system contains four other Level blocks: DiningVolume, KitchenVolume, Offi-
ceVolume, and RestroomVolume. Let's also assume that you apply another preset (called Dining) that con-
tains the DiningVolume block, but no other blocks. After applying this second preset, the working values in
the LobbyVolume block reflect the Lobby preset, the working values in the DiningVolume block reflect the
Dining preset, and the working values in the remaining blocks remain unchanged from their beginning
values.
You should now have a basic understanding of how a preset affects the working values of a system. But
there's more to learn before you can work effectively and efficiently with presets. For example, as you have
seen in this example, you can layer presets on top of one another, with each preset affecting only the blocks
it contains. All other working values remain the same. But what happens if the same parameter is contained
in multiple active presets with a different value in each one? And here's another question: Once you turn a
preset on, can you turn it off?
Keep reading to learn more!
What happens if the same block exists in multiple active presets?
You can include the same block in as many presets as you want (although we recommend against including
the same block in different preset types—see the next section for details). So what happens if more than one
of those presets is active? How do you know which preset values are used by the system?
The preset values that take precedence are always the ones most recently applied to the system. In other
words, the system keeps track of the presets as they are applied and places them in priority order. If you apply
PresetA, then PresetB, then PresetC, the Active Presets list
1
(which you can view in the All Presets dialog
box) would like this:
1
A dynamic list of active presets maintained by the system that changes as presets are asserted, activated, and deac-
tivated. The presets are listed in priority order. When a preset is asserted or activated, it goes to the top of the list
and its parameter values overlay the current working values for the corresponding system parameters. When a pre-
set is deactivated it is removed from the list.
HAL SYSTEM DESIGN GUIDE
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