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Not Quite Easy?Yet

button. It's encouraging to get instant feedback on how smart you are. But it doesn't always work that way.


The problem isn't with the gear. The vast majority of professional (and some consumer) equipment is well built and meets its minimum performance and technical specifications for signal-to-noise, gain, etc. The problem lies with technicians not understanding how to make the necessary measurements and adjustments to the gain structure of the system. Once they've been shown how to adjust the system and tried it themselves, the equipment or manufacturer comes off their “Don't Touch” list.

A major reason our technical people sometimes have this mindset is that they do live in a digital world. We are seduced by technology's promise that anything digital is automatically easier and better than analog, forgetting that the vast majority of systems still contain analog equipment and that a good portion of digital components are still analog-in and analog-out.

In a quick mental rundown of the systems I have designed over the past year, all of them had some analog equipment in them. Unless we pay attention to how those analog components are integrated with a digital core, the potential for gain and signal-to-noise problems remains. It is similar to case for using fiber optics, which promise to eliminate the potential for ground loops and induced noise. But that's true only if the devices on each end of the fiber are already free of noise. If not, fiber can be just as effective at transmitting noise as it is at transmitting a clean signal.

I posed a series of questions to my fellow consultants a few weeks ago:

  • How many of you currently require a contractor to measure and report electronic signal-to-noise ratios (SNR) in your specifications? If so, do you specify how that measurement will be made?
  • If you don't, do you take that measurement yourself without the contractor's assistance?
  • Are your SNR specs the same for every venue? How do they differ?
  • What share of contractors do you think actually know how to take the measurement?

These are issues that the Electronic Audio Noise Task Group, a part of the Project Commissioning Working Group (PCWG), is working through as it defines the how and the why of electronic audio noise measurement and system gain optimization. The PCWG has been organized by InfoComm International as part of an effort to create a suite of best practices that will help guide the industry through the process of commissioning audiovisual systems.

It is not something that will take place overnight or without the efforts of the entire industry. The Noise Task Group comprises manufacturers, consultants, and system integrators. We all recognize the vital role that well designed, properly installed, and adequately commissioned audiovisual systems play in the health of our industry and the satisfaction of our clients.

Hopefully we'll all get to tap that “Easy” button as we work to understand the importance of this issue (among others) and train installation staff in proper commissioning procedures. The result will be a greater level of confidence in our knowledge and capabilities. This translates directly to the bottom line and profitability of our industry.

That should be really easy.

Thom Mullins is a senior consultant with BRC Acoustics & Technology Consulting in Seattle. He can be reached at

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