The idea of using digital signal processing (DSP) to convert digital audio data sampled at 44.1kHz or 48kHz to a higher sample rate is not new. I first heard the beneficial effects of upsampling at Stereophile's 1998 hi-fi show in Los Angeles, where a pro-audio dCS 972 digital-to-digital processor was being used to convert 16-bit/44.1kHz CD data to a 24/192 datastream.

January's Industry Update included a report on a scientific article presented at last year's AES meeting, in which the authors used test tones and a modest audio system (albeit in an anechoic chamber) to prove that listeners can discriminate between high-rez and CD-rez audio. This is important because scientific evidence of an audible difference between high-rez and CD-rez music is considered weak by some, even as anecdotal evidence grows stronger by the day.

As I pondered this, I recalled a recent paper I'd seen in the Journal of the Audio Engineering Society but hadn't yet read. "High Resolution Audio: A History and Perspective," which the AES has made available free online, does precisely what the title says: reviews the history of digital audio beyond CD-rez and frames the issue of high-rez audio's audible superiority on the basis of the available evidence.