Installation guide

About Control Links
This section contains the background information you'll need for working effectively with HAL System control
links. What you need to know, however, depends on what you're trying to do:
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Are you creating links that connect only one control to another, with each control participating in only one
link? You'll find everything you need in Basics of Control Linking. Reviewing the Best Practices section is
also a good idea, but you can skip Advanced Topics.
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Are you creating links that connect three or more controls? You should review Basics of Control Linking,
Advanced Topics, and Best Practices (in other words, read everything!).
Basics of Control Linking
What is a control link and why would I want one?
We'll start with a question for you. What good is your brilliantly-designed audio system if it doesn't provide
end users with any control? Of course, the answer depends entirely on the situation. But, in most cases, users
need control over such things as volume, music selection, preset activation, and more. And they don't want to
have to go into the Halogen software to obtain this control. You don't want them in the software either! So
how, in a HALSystem, do you give users control out in the locations where it's needed?
The answer? Control links!
Control linking allows you to tie two or more system controls together so that they work in tandem. Let's say
you want to allow end users to adjust volume in a specific location. One way to accomplish this is to install
a DR1 in that location and, in Halogen, link the level control for that DR1 to the Gain property of the appro-
priate Level processing block in your design. This link causes these two controls to track one another.
Change the volume on the DR1 and the Gain in the Level processing block changes. Change the Gain in the
Level block (from within the software) and the DR1 changes.
There are countless situations for using control links. Volume control is probably the simplest and most com-
mon scenario. But HAL and Halogen are ready and able to accommodate much more complex linking needs.
Read on to learn more.
NOTE FOR DRAG NET USERS: Control links in a HAL System serve the same purpose as Groups in
DragNet.
What controls can Ilink together?
A control link connects (or links) two or more system controls to one another. So, in essence, you could
include any system control in a control link, right? Well, no. Because the primary purpose of control linking
is to expose controls to end users, only those controls that could be useful to an end user are actually link-
able within Halogen. These include such things as level controls, selector controls, and so on. For details on
the various control types, see below.
NOTE: You cannot link different types of controls to one another. For example, you cannot link a level
control to a selector control.
How do I know if a control is linkable?
If a control is linkable, it displays a link icon, as shown below:
HAL SYSTEM DESIGN GUIDE
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