You're referring to this
"In one brief test with two subjects we added 14 dB of gain to the reference level quoted and tested the two sources with no input signal, to see whether the noise level of the CD audio channel would prove audible. Although one of the subjects was uncertain of his ability to hear the noise, both achieved results of 10/10 in detecting the CD loop. (We have not yet determined the threshold of this effect. With gain of more than 14 dB above reference, detection of the CD chain?s higher noise floor was easy, with no uncertainty. Tests with other subjects bore this out.)"
I'm referring to this
"4 A NOTE ON HIGH-RESOLUTION RECORDINGS
Though our tests failed to substantiate the claimed advantages of high-resolution encoding for two-channel audio, one trend became obvious very quickly and held up throughout our testing: virtually all of the SACD and DVD-A recordings sounded better than most CDs? sometimes much better. Had we not ?degraded? the sound to CD quality and blind-tested for audible differences, we would have been tempted to ascribe this sonic superiority to the recording processes used to make them.
Plausible reasons for the remarkable sound quality of these recordings emerged in discussions with some of the engineers currently working on such projects. This portion of the business is a niche market in which the end users are preselected, both for their aural acuity and for their willingness to buy expensive equipment, set it up correctly, and listen carefully in a low-noise environment. Partly because these recordings have not captured a large portion of the consumer market for music, engineers and producers are being given the freedom to produce recordings that sound as good as they can make them, without having to compress or equalize the signal to suit lesser systems and casual listening conditions. These recordings seem to have been made with great care and manifest affection, by engineers trying to please themselves and their peers. They sound like it, label after label. High-resolution audio discs do not have the overwhelming majority of the program material crammed into the top 20 (or even 10) dB of the available dynamic range, as so many CDs today do."
There is no lack of a positive result - http://www.aes.org/e-lib/browse.cfm?elib=15398
If you'd like to replicate it ...
- Recording microphones (a pair of Sennheiser MKH 8020), FR of 10Hz-60kHz.
- Two stereo feeds from the mic preamp (Millennia HV-3D) to two Micstasy ADCs, one set to 44.1/24 the other to 88.2/24
- Test signals: five musical/instrumental (orchestra, classical guitar, cymbals , voice, violin) recordings from live performances, taking place in several halls/rooms with varying dimensions & acoustics.
- For use in tests, 5-8 sec excerpts were used, with no processing except fade in.out via Pyramix 6 software.
- The 88.2 excerpts were downsampled to 44.1 via Pyramix software, so there were three sets of signals, native 44.1, native 88.2, and downsampled 88.2-->44.1.
- Playback: 5 blocks corresponding to the 5 excerpts, 12 trials per block ( i.e. all pairwise combinations of the three versions, each presented 4 times, twice in each of the two presentation orders), randomized ABX protocol.
- Playback hardware was an RME Fireface 800 DAC, a Grace m906 monitor controller, and a Classe CA-5200 stereo amp, feeding a pair of B&W 802D loudspeakers (FR 70Hz-33kHz).
- To avoid clipping a 750ms switching interval was employed, set in the user interface which was Cycle '74's Max/MSP/Jitter software package, all playback was at 24 bits.
Note: In my personal opinion, I think the 750ms interval is good. I think rapid or immediate time aligned switching in ABX could cause an illusion that two sounds are the same.
This test used very well controlled recordings completely under their own jurisdiction (unlike other tests selecting titles randomly, without knowing the recording technique involved).
High-rez isn't necessarily about hearing above 22.05kHz. If that were the case, I'd suspect an extremely limited number of people could perhaps hear information in the 22.05~26.00kHz range, with a very subtle difference in overtones and such, however it that were the case I'd declare it as a useless format.
Clearly, recording at 1Hz~100kHz is truer to reality, especially if it removes the need for all kinds of filters.
When you start discussing the various side-effects and designs of these filters, whether the extended frequency range is actually perceivable or not, and discuss the hardware limitations or performance of various ADC / DAC chips or if your speakers have IMD, it starts to become very academic. You could ill-quote different spec sheets all night, it just depends on the scenario of the situation, and the same rule applies to all listening tests looking for transparency, they are limited to the equipment in the scenario and human perceptivity.
Just to OT for a moment, Lavry says about 192kHz " the negative consequences of the reduced oversampling ratio far outweigh any benefits derived from the higher sample rates."
Really? My DAC states "...this DAC has up to 10 times less out-of-band noise compared to anything similar on the market today. It also has the capability to accept a 216KHz sample rate while keeping the same digital filter oversampling rate and the same speed of the modulator."
It all seems situational to me.
My current DAC costs less than $200 and SACD's are pretty cheap, with lamented higher sound quality, so I don't see how the marketing side is an issue either, DSD/.DSF playback will come down in price eventually.
The marketing to watch out for is fake high-rez and fake DSD. You can do this with a program like http://spectro.enpts.com/, but as high-rez content becomes more popular the content above 22kHz could be fabricated as well.
All in all microphones, speakers and the music itself is 6000 times more important than this sector, but I really fail to see the issue in trying to improve every component in audio playback to it's highest potential or slightly beyond.
For musical enjoyment I'll keep listening to 92 kbps MP3 with $10 Sony earbuds, but for the curiosity and intimacy of audio playback I'm very happy to try DSD and headphones with an FR like this... whyever not?
On the 750ms switch, this is to prevent audio illusions rather than introduce them, small differences are a lot more "visible" with quick change because our brains, with time, disposes audio memory and inserts its own perception of the audio into our hearing. Harmon studies have shown that quick change blind testing with trained listeners are a lot better than long term testing.
On 192khz, I don't think our ears are really trained/tuned for ultrasonics http://people.xiph.org/~xiphmont/demo/neil-young.html
On high resolution mics with extended HF range, obviously recording with such mics have a sure benifit which is off course, transient response but to me, thats about it.
But anyway, high rez whether fake or real, the mastering of such recordings are very well taken care of, the few SACDs I own have better mastering than their CD originals.