Best of Awards
- Written by The SECRETS Editorial Team
- Published on 30 November 2011
Technologies on the Rise
Technologies on the rise: Digital Audio
There was a spirited discussion among the Secrets Editorial staff as we worked to frame an award around the ongoing development of digital audio. Most of us agreed that the reproduced sound quality of digital sources continues to advance. The pace of progress in sound quality unfolds in fits and starts with the next major advances most likely taking place on the software side.
Meanwhile, high resolution audio is on the rise with more access and availability than ever before. It doesn't really matter whether you choose to get your high resolution music through physical media, downloads or through streaming. They can all be very good. And with any of these sources, control is in the hands of the user. This is not a "push" technology like traditional radio or television.
But it doesn't stop there. Current research and development on micro transistor architecture holds the promise of chips that will be smaller and faster with lower power demands than ever. Combine this with advances in Class D amplifier technology and one can expect more powerful and higher quality digital audio devices in the future.
There are lingering concerns about the future commercial viability of high resolution audio. These concerns center on the uncertainty of upcoming copy protection demands of the major labels and that a majority of consumers are still perfectly happy with the sound of their MP3's.
The Award Summary Statement.....
"High resolution music delivery is at an inflection point with enhanced quality, more variety, improved networking and component miniaturization."
It looks like we are entering a brave new era of digital audio with a bright and exciting future.
Senior Editors: Jim Clements, Dr. David A. Rich, Chris Eberle, Jason V. Serinus
Technologies on the Rise: Room-correction systems with PC control in the hands of the consumer
DSP-based room-correction filter coefficients are determined from microphone measurements during calibration. The ability of the room-correction system to enhance the sound of the system is heavily influenced by the quality of the algorithms that calculate the filter coefficients; these algorithms often represent 90% of the development time of the best products.
Computing the model's coefficients has typically fallen to a DSP chip on board the AVR. The DSP is designed for real-time signal processing, making it ideal for the signal processing aspect of this application. The DSP, however, falls short when tasked with off-line computations. To circumvent this issue, room-correction algorithms have often been deliberately simplified, thereby sacrificing the quality of the model's parameters for the sake of compute speed.
A PC is better suited to calculate the model's coefficients. In turn, as algorithms are improved, all that is required is a software update. The coefficients calculated by the PC are transferred to the AVR so the DSP can go about the work it was designed to do. The PC to AVR interface also transfers test tones produced by the speaker during calibration. Newer AVRs, with more powerful DSPs, perhaps from a different silicon supplier, are capable of more accurate real-time filter computations. Only minor changes must be made to the PC software to ensure compatibility. Time to market of the next generation systems is accelerated compared with an AVR that does not port calculations to a PC.
Visualization is a second advantage of the PC-based systems. For example, the PC can display frequency response data (before and after correction) and may offer numerous control options such as the ability to control the shape of the corrected frequency response (flat is often not optimal) and the ability to limit the frequency range that the system corrects.
Access to the PC software had been the sole domain of third-party installers. Anthem has broken this model, offering its best PC software on all products although higher priced Anthem Pre/Pros have more DSP computational power. Anthem provides a calibrated USB microphone, making practical PC-based room correction by the consumer. The need for analog mic cables, external microphone preamps, and ADCs has been eliminated. With the program in the hands of the consumer, there is significantly more time to listen and adjust in an iterative fashion
The Anthem system uniquely takes advantage of the PC to permit the user to optimize speaker placement and listening seat position. A real-time display of the room response updates continuously. One seeks to minimize response variations before correction to achieve better post correction results. Installers have separate expensive equipment to do this.
The AVR/PC interface is the first step towards shoe-horning the complete room correction into the PC for a computer-based music system. Modern PC microprocessors can handle real-time DSP computations. These systems are evolving rapidly, but they are not far enough along to approach the performance and ease of use currently offered in the Anthem PC / AVR system. Applications are limited to the space where AVR functionality is not required.
Senior Editor: Dr. David A. Rich Editor-in-Chief: Dr. John E. Johnson, Jr.