Reference: StudentFilmmakers Magazine, December 2007. Audio for the Digital Age: More is Better? by Bryant Falk. Pages 30 & 31.
With the ever-growing popularity of HD video and the numerous high-def options such as HDVD and Blu-ray Disc, it seems like audio is being left behind. What actually is the future of audio? Well, it’s come a long way from its wax cylinder beginnings, and is quietly marching onward and upward.
Digital audio is currently going the route of more is better. Instead of 48 kHz 16-bit digital recording, you now have options as high as 24-bit 192 kHz sampling. These higher rates have both benefits and drawbacks. The first big plus is the ability to represent the audio with more accuracy and less noise. Another plus is a larger dynamic range. This means more ability to record very quiet and very loud moments without distortion.
Recording on location at these higher rates and with multiple tracks leads you straight to some type of computer-based system, whether Pro-Tools, Logic, Digital Performer, or the myriad of other software systems available. This coupled with a breakout input device and, you’re capturing some serious audio.
Drawbacks include shelf filtering to minimize aliasing issues and dither to keep samples within trackable range. These things have always been the bane of digital audio.
Arriving on the scene is a revolutionary way to record audio. Actually, the concept is not new at all. Back in 1992, Dr. Yoshio Yamasaki from Waseda University came up with a unique way of using the digital system to translate analog sounds into a very accurate digital representation. In what will be a super simplified description I will try to describe his process.
Our current digital audio systems represent audio using bit rate and sample rate, giving both as much as possible to represent the audio, (16 bits at 48 kilohertz). Dr. Yamasaki’s idea was to give his system huge amounts of sample rate, (5.6 megahertz) and a super small bit rate, (one bit, zero or one) and follow the path of a sine wave up or down through time. Think of it as drawing a picture blindfolded with only having to worry about whether or not to move your pen up a notch or down a notch, but the space between each move was smaller than the width of a hair. Also, the usual drawbacks of digital go away as it’s not necessary to dither or shelf filter with this system.
The idea worked great but required huge amounts of data storage and computing power. But now, 15 years later, with the availability of large hard drives and amazing processor speeds, the dream may just be a reality.
The Korg M100 is one of the first recording systems using this one bit technology, with many more software-based systems fast on their heels. This new type of digital recording allows for a very accurate recording system – so accurate, in fact, that it may replace other systems for archiving final projects. Unfortunately, with the massive data requirements a multi-track system is still in the distant future.
The irony to this future vision stuff is, who knows, we actually may come up with some new organic system of recording that will bring us full circle to a new form of analog. Or, possibly a combination of the two.
Bryant Falk has been a producer and engineer for over 12 years working with such clients as The Ricki Lake Show, Coca-Cola, Sports Illustrated, Valley National Bank, and MTV’s The Shop. His company Abacus Audio handles many aspects of the audio production field from creative and production to mixing and final output.
website: www.abacusaudio.com.
