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Open HLX provides a set of iOS apps for setting up and/or interacting with the Audio Authority HLX Series Modular Matrix System High Definition Audio/Video Switching System, which has gone end-of-life and, as a result, is no longer manufacturered or sold by Audio Authority.
However, thousands of such systems have been sold worldwide and there remains a need to set up, interact with, and control such systems.
With that in mind, Open HLX provides the following iOS apps:
- Open HLX
- A user-centric app, with the ability to change the volume level, volume mute state, and source (input) for any group or zone.
- Open HLX Installer
- An installer-centric app, with all of the features of Open HLX, that adds additional installer-centric functionality such as modifying zone stereophonic channel balance and zone equalizer sound modes and sound mode settings including: zone equalizer band levels, zone equalizer presets, zone tone bass and treble levels, and zone high- and lowpass crossover filter frequencies.
Despite its end-of-life status, the HLX Series remains a high-value and high-function audio/video matrix unrivaled and unparalled even among actively-sold and -produced competitive products.
In most situations, an HLX system will find itself with its telnet-based Ethernet network interface disabled and tethered, via a serial cable to an AMX, Crestron, Control4, or other controller where those systems act as the primary user interface and experience surface with the HLX acting silently in the background. For such installations, Open HLX and this package will be of both little use and interest since AMX, Crestron, Control4, or other controller already is providing the functionality of the Open HLX mobile apps.
However, despite its strong performance and value, whether using its serial interface or the aforementioned network interface, the implementation of the HLX Series control protocol has two notable limitations that severely limit its use as a general audio/video matrix without an intervening controller.
First, the HLX is limited to no more than two active telnet-based network connections. This means in a consumer/residential or commercial/enterprise environment, no more than two Open HLX mobile app users may be active at a time. Given the short background time out of the Open HLX mobile app on iOS, this may not be a practical day-to-day limitation, depending on the number of concurrent users for your installation.
Second, and perhaps more limiting, is the fact that the HLX Series control protocol does character rather than line or buffer at a time input/output and multiplexes across multiple connections at that granularity. There are two implications of this. First, the response is incredibly slow. This can be seen in the Open HLX mobile apps after connecting while the app is gathering the latest HLX state from the HLX hardware. This operation can take a frustratingly-long 15-20 seconds. Second, particularly when more than one connection to the HLX is active, the output among any client is interleaved, resulting in unparseable and, by extension, corrupt output. This renders concurrent mobile app usage all but unusable when more than one command request and/or response is in flight. However, like the first limitation, this may tend be either more theoretical or more practical, depending on the number of concurrent users for your installation. If you note very strange behavior in the mobile app, including nonsensical group, source (input), or zone names, your mobile app may be getting its command request/response stream intermingled with another mobile app user.
Despite these two limitations, the Open HLX mobile apps represent a highly-effective way to directly interact with HLX hardware without the need for an intervening controller.
Open HLX is an Xcode-based project and, as a result, those interested in building Open HLX from source are expected to have a practical knowledge of using Xcode.
In addition to depending on C, C++, Objective-C, and Objective-C++ languages; the C and C++ Standard Libraries; and the C++ Standard Template Library (STL), Open HLX depends on:
For openhlx in particular, Open HLX builds the package natively within Xcode, relying upon an expanded archive distribution or source code control clone of it from which to build it. openhlx uniquely depends on:
and Open HLX shares both the LogUtilities and nlassert dependencies. However, all four of these dependencies are satisfied for both by the openhlx package itself.
Satisfying the openhlx dependency and its sub-dependencies may be accomplished by setting the OPENHLX_ROOT build setting to the absolute path to a openhlx source distribution--either an expanded archive or a source code control clone. This may be done either in Xcode itself or on the command line with xcodebuild:
To set OPENHLX_ROOT using Xcode itself:
- In the leftmost project inspector, click on the "openhlx-ios" project.
- In the editing window that appears for "openhlx-ios.xcodeproj", select the PROJECT > "openhlx-ios", just above the list of targets in TARGETS.
- Click on "Build Settings".
- Search for or navigate to "OPENHLX_ROOT", which should be under "User-Defined", likely at the bottom of the settings list.
- Enter an absolute path value for OPENHLX_ROOT, such as "/Users/gerickson/git/github.com/gerickson/openhlx".
When building the project targets from the command line using xcodebuild, simply set OPENHLX_ROOT with a key/value pair option such as:
% xcodebuild ... OPENHLX_ROOT="/Users/gerickson/git/github.com/gerickson/openhlx" ...
Q: I do not have Audio Authority HLX hardware; however, I would like to try out Open HLX. How can I do that?
A: The core package on which Open HLX is based, openhlx, contains an executable, hlxsimd, that fully emulates the protocol and virtual behavior of real HLX hardware. An instance of hlxsimd can be built, launched, and Open HLX can be targeted against that using whatever IPv4 or IPv6 address hlxsimd has been configured to bind against and listen on.
Q: What features of HLX hardware are not supported?
A: There is no support at this time for favorites, restrictions, or audio/video breakaway switching.
There are numerous avenues for Open HLX support:
- Bugs and feature requests - submit to the Issue Tracker
Open HLX follows the Semantic Versioning guidelines for release cycle transparency and to maintain backwards compatibility.
Open HLX is released under the Apache License, Version 2.0 license.
See the LICENSE file for more information.