October 30, 2007 The issue of TV audio variation across channels and during commercial breaks is one which affects most of us – in fact, rushing for the remote to dampen the sound when an ad breaks in at uncomfortable volume has become the modern day equivalent of the quick-draw. Solutions to this problem have been sought for years with varying degrees of success, but now a new technology unveiled by Dolby promises to provide “set and forget” volume-leveling while preserving the full listening experience at any volume level.
The new audio processing technology known as Dolby Volume claims to solve one of the most prevalent problems with existing TV audio using a model of human hearing developed over 40 years of audio research. This means that the system measures, analyzes, and controls volume based on how humans perceive and organize sound, faithfully reproducing stereo or multichannel audio signals at any desired playback level and avoiding the sound degradation to which existing solutions that rely on audio limiting and compression technologies are prone – particularly at lower volume levels.
The system works via two key features – a “Volume Leveler” maintains a consistent sound level set by the viewer regardless of the channel or program, and a “Volume Modeler” ensures a full-range of audio is experienced at any volume setting by dynamically adjusting the bass and treble.
In “dynamically adjusting” audio output the system applies principles of psycho-acoustics – the science of how the human brain perceives sound. At higher volumes the brain hears “flat” sounds with the bass, treble and mid-range leveled out, but at lower volumes your brain misses bass and treble elements and your ears become sensitive to only the mid-range. This is where Dolby’s modeling technology steps in to compensate for the brain’s natural tendencies and continue to deliver all the nuances of the soundtrack based on what we actually hear.
As a licensed technology, Dolby Volume will be pre-installed in TV sets and AV receivers but no word as yet on which manufacturers will be utilizing the system.
The applications also go beyond simply making the experience of watching TV more enjoyable – when switching the input to a media player or games the pre-set volume level will still apply, a particularly useful feature given the tendency of CDs ripped from different sources to vary wildly in terms of volume output.
First announced at 2007 International CES, Gizmag was suitably impressed by Dolby’s demonstration of the system at this year’s IFA in Berlin and we will watch closely for announcements as the technology makes its way to market.
A PDF white paper from Dolby on the topic is available here.
