Introduction to Technology¶

The Symetrix Audio DSP system utilizes several key technology features to allow commercial audio contractors to do their jobs better. Computer control of remote DSP-based audio hardware for routing and processing is the primary goal of Symetrix, and this paper serves to describe some of the technologies used to achieve that goal.

Composer is a Windows application that configures and controls the Symetrix hardware. Composer uses CAD technology to allow the audio system designer to construct digital audio processes much like electrical engineers design hardware. The designs are generated by the designer are quickly compiled and downloaded to the target hardware with a single button press.

The Symetrix CAD approach does not limit the system designer to a collection of processes, or even a set of collections, pre-determined at the factory. The user is able to, module by module, select any number of processes needed to perform a particular job. A "Run-time linker" is used to facilitate this flexibility. The DSP processing code for each process is modularized in a code file. When the user downloads the design, the code files for all the modules chosen are dynamically and automatically placed on one of four powerful floating point DSP engines within each Symetrix hardware unit. DSP and memory resources are assigned to each instance of each module in the design as they are available. In addition, the connections between modules are implemented by "linking" the memory locations of different modules.

Much like a CAD program, Composer maintains a "Net List" or connection list between processing objects. This Net List can be viewed or printed as a list of point-to-point connections. Symetrix is also capable of performing electrical rules, by checking on and graphically highlighting those connections which the user has made, which can not be interpreted.

Connections are not limited to these automatic connections within a single hardware unit. The user can bus up to 128 channels - via the digital audio protocol named Dante. These channels can be routed between physically separate hardware units. This is performed by placing Network Transmit modules, as needed, into the design. These modules provide a one-to-many gateway to other units on the Dante network. This allows individual designs to be kept to a manageable size, while providing a mechanism to build huge multi-unit processing architectures. Composer allows the user to push an updated design to all units on the Network at once while keeping all designs in a single file or hardware preset.

Composer is a full-featured application providing all the features power users of CAD programs have come to expect. This includes drag and drop editing, multi-level undo and redo, programmable auto-save, wire-frame select, re-sizable and the ability to customize the interface to particular markets through the use of color, fonts, bit maps, and added text.

Of particular interest are Control Screens. This feature allows the contractor to create custom interfaces that can be edited by the integrator, but operated by the facility's technical staff, or other non-technical end-user. Advanced security features allow end-user access to just those control aspects that the contractor or system designer deems allowable.

Super-modules are another of Composer's advanced features. Super-modules allow complex multi-module designs to be created, labeled and represented as one module. These super-modules can then be placed repeatedly in one or more designs as needed.