I received an email recently from a customer asking why didn't AIX Records/iTrax.com use 192 kHz instead of our current top sampling rate of 96 kHz. I offered the following straightforward response.
AIX Records was one of the very first record labels to capture, mix and release new HD tracks using equipment that was capable of the faster sampling rates and longer word lengths necessary to enter the world of high definition audio...namely 96 kHz/24-bits. Our release target was the new DVD-Audio format, which came out in 2000 after the success of the DVD-Video format. While most labels were simply rehashing older standard definition tapes from their archives (a practice that is still very much with us through so-called "HD download sites"), I felt it was necessary for consumers to have access to new recordings that would actually show an audible improvement over analog tape and vinyl.
The new audio-centric DVD flavor was supposed to be the replacement to the aging CD. But unfortunately, it failed due to a number of reasons not the least of which was the introduction of a competing format in the form of SACD, which was heavily pushed by Sony and Phillips (they have both ceased support of the format). However, the production path to DVD-Audio and SACD offered the "potential" for better fidelity. For advocates of PCM audio (the type used on CDs and DVD-Audio) if you wanted to produce music at higher sampler rates and longer word lengths, you had to acquire the new high resolution equipment. Unfortunately in 2000, there were very few choices.
The ubiquitous ProTools digital audio workstation from Digidesign is used on virtually all record projects and film scoring dates. It is a capable tool but until 2011, it's internal process was insufficient for HD audio and their internal timing errors made it unusable for audiophile projects...at least in my opinion. I researched many approaches for HD recording and settled on a machine fro Euphonix, a bay area equipment maker that is still producing some of the finest digital consoles for large studios. I leased an all digital console called a System 5 with 64 inputs and an R-1 36 channel HD recorder/reproducer. There was only one other console that was available at the time from a competing UK company. Both of these machines maxed out at 96 kHz/24-bits and represented an investment of over $250,000.
Thus the simple answer to the question of why not record at 192 kHz/24-bits is that I don't own equipment capable of capturing and mixing natively at that rate. But there's more to the story...is it really necessary to move up to 192 in order to capture another octave of HF partials? Perhaps but I'm still waiting for the formats that will allow us to deliver the higher sample rate on disc or via downloads. Remember the files double in size when you move from 96 to 192 kHz.
The fact remains that virtually all so-called HD recordings do not have any apparent sound above 25 kHz and reproduction systems, especially speakers, cannot reproduce frequencies above about 40 kHz. Traditional recording techniques for capturing classical music places the microphones at least 15-20 feet away from the instruments. With the inverse square rule (which states that the amplitude of a sound diminishes by one over the distance squared...or simply put...the further you place the microphones away from the source the less the signal you will hear), there is not much sound captured between 25-48 kHz. At 96 kHz, it is possible to record up to 48 kHz partials...and AIX Records does. Our spectragraphs show substantial amounts of sound between 25 - 45 kHz (whereas SACD recordings, which might be able to record and reproduce these high frequencies avoids delivering them because of the noise shaping required to make DSD work in the audible band). So in my humble opinion, moving from 96 to 192 makes no difference in the resulting sound of a particular recording.
Would I opt to record at 192 or even 384 kHz if I had the chance? Yes, I would but my equipment and the practical realities of audio in 2011 makes it unnecessary. When the rest of the record labels start delivering sound above 30 kHz (which we already do), I'll revisit the question.
I'll finish with this quote I located online discussing the relative merits of 192 kHz…
"I am hoping 192 KHz will die the death it deserves, because it is without any value over 96 KHz, which already provides well more than enough headroom in sampling rate for the most critical audio recording and playback imaginable.
I speak as an engineer (EE), but the forces of marketing, advertising hype, and anecdotal claims are powerful ones in today's market. And there are development engineers (EEs) who are forced to comply because corporate management compels them to and their salaries depend on it."