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DACS: Application Analysis
 
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Application Analysis

In order to properly form a set of specifications for the components of DACS, a set of potential applications of the system was derived. Four contexts were chosen: a home studio setup, a broadcast application, a theatre application, and a live sound application. Figures 1, 2, 3, and 4 show schematic representations of these possible configurations. In each figure, shaded boxes indicate custom hardware, developed in this MQP. Unshaded boxes indicate off-the-shelf hardware. Custom software runs on each of the computers present in the diagrams. The diagrams have since gone through many iterations since the initial diagrams, hence now reflect actual details of the DACS implementation. Initially, several different diagrams were drawn, out of which these evolved.

Figure 1: Typical DACS-based home studio configuration.
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\psfig{file=intro/applic-studio.eps,width=6.5in}
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Figure 2: Typical DACS-based broadcast application.
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\psfig{file=intro/applic-bcast.eps,width=6.5in}
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Figure 3: Typical DACS-based theatre audio application.
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\psfig{file=intro/applic-theatre.eps,width=6.5in}
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Figure 4: Typical DACS-based live sound application.
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\psfig{file=intro/applic-live.eps,width=6.5in}
\end{figure}

Through studying potential applications and applying what was learned with the previous system, a rough set of specifications was derived. A partial list is shown below:
  • Custom audio hardware should support balanced and unbalanced line-level signals.
  • Custom audio hardware should be of semi-professional studio quality, dictating relatively low noise floor and THD specifications. This is an important improvement over the original system, which had noise problems.
  • Integration with existing MIDI systems would be beneficial, both in terms of functionality and in terms of reduced time expenditure. This integration would not only include MIDI hardware, but existing MIDI sequencing software.
  • If possible, existing audio control standards should be used, to provide compatibility between devices.
  • Some applications are set in an environment where syncing to SMPTE time codes would be beneficial for automation purposes.
  • Overall, the system needs to be flexible, and dynamically expandible and configurable.
  • An intuitive, lucid way of programming and controlling the system must be created. A major shortcoming of the original system was the lack of a decent user interface.
  • The use of inexpensive off-the-shelf hardware, such as CD-ROMs for compact disc cueing, provided a significant cost advantage in the first system. This concept should be applied to the DACS.
The two pieces of custom hardware, the DACS mixer and the DACS control board, were settled upon as reasonable devices to design and prototype for the MQP. Other pieces of application-specific hardware were considered, but these two pieces of hardware were applicable to all of the applications considered in the analysis. The DACS mixer is the core of the system, thus it was quite clear that its implementation was necessary. The board was implemented because it is believed that it brings a significant improvement to the usability of the system. The remaining DACS components, firmware and software, were developed to the extent that time permitted.
next up previous contents
Next: System Overview Up: Introduction Previous: Design Methodologies   Contents
Steve Richardson 2000-07-06
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