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Meeting held Wednesday, January 29th, 2014, Digipen Institute of Technology, Van Gogh Auditorium
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Meeting held Wednesday, January 29th, 2014, Digipen Institute of Technology, Van Gogh Auditorium
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The PNW Section January 29, 2014 meeting presented James D. (JJ) Johnston talking about the
confusing issue of audio dynamic range. In addition, Bob Smith added a demonstration of
software for measuring and displaying various interpretations of level or loudness on a DAW.
Johnston is a current Governor of the AES and an AES Fellow, and one of the inventors and
standardizers of MPEG 1/2 audio Layer 3 and MPEG-2 AAC. Smith is an audio engineer with
Physio Control and runs BS Studios.
About 60 attendees, about 23 AES members amongst them, gathered at the Digipen Institute of Technology in Redmond, WA. JJ set about to clarify some of the issues trying to describe dynamic range. He discussed problems quantifying numbers while dealing with perceptual response, as well as non-perceptual devices. For one, there are few standards. Often, numbers are bandied about that have little correlation to the process being described, or are really inadequate. He went into loudness (a sensation level) vs. SPL, intensity, and other strict definitions. Should you measure peak levels vs. noise floor? What about RMS levels? What about levels that are frequency dependent? A single number is basically inadequate to really tell much. JJ would prefer seeing a graph of frequency vs. peak and noise floor levels. This would be the best way to determine proper gain structure in a system. And "A" weighting is wrong here. With perceptual work, the issues of dynamic range are even murkier. Short and long term dynamics come into play. He spoke about the television issues of the CALM Act, and the BS1770 loudness spec. Using sones or phons would be fine for perceptual measurements, which can't and won't correlate to a simple dB number. JJ showed several graphs of music samples' dynamic range, using open-source software (Octave). The scripts were placed online so participants could experiment themselves. Examples of vintage rock, modern pop and classical music were shown. After a break, door prizes were awarded to:
After the break and prize awards, Bob Smith (Physio Control; BS Studios) presented on products
available to display "loudness" levels on your DAW. Included were:
Reported by Gary Louie, PNW Section Secretary |
Last modified 05/26/2016 2:22:52.