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Here, FRS stands for Full-Range Sound and HCS for High-Cut Sound (nothing above 20kHz). Wouldn't you agree that the same has been said about SACD Vs. redbook |
I, too, have paid attention to this research. I have a few problems with this:
(1) IMD(intermodular distortion) of the system at it's two settings was not measured/published, and correlated to a known threshold for human hearing tolerances(requring reference too or a new study in itself).(A BIG ERROR). Mention of IMD was made one time in the paper, and no specific data was provided. They also slightly mis-state that it should not be a problem in this test. To be specific, they quoted:
"To overcome this problem, we developed a bi-channel sound presentation system that enabled us to present the audible LFCs and the nonaudible HFCs either separately or simultaneously."
Problem is, that IMD is an artifact that will be caused by mixing the signals at line level OR at the acoustic level. It escapes me why they seem to think this is not the case. If one worries that it may be in the 'original' signal, well, a precision 44.1/16 recording/playback system will record ALL of the audible fundamentals of this distortion IF it was originall present. The form of IMD here, the problem is, is likely to be a result of the playback system itself. From what I can gather, they basicly had a supertweeter they engaged/disengaged. Another noteworthy point is that that could not induce these 'results' with the high frequency content alone. They state :
"Moreover, it is the combined presentation of HFCs and LFCs, not HFCs alone, that specifically induces the enhancement of alpha-EEG and activation in the deep-lying structures"
Further concern and investigation should be given to IMD content of the system, especially after this result.
A pertient fact omitted here when mentioning the 1978 study, is that the test subjects were all audio professionals with trained hearing skills, and proper statistial analysis and testing methodology was used. It's held up to scrutiny for over 20 years now. I only mention this becuase they keep citing this old study as if their new test is demonstrating credible different results.
(2) In the case of the 'subjective listening test', a standard accepted statistical/testing format was not used in this study.
Thus, this study is not accepted as a standard. If the researchers want to establish, as a standard, that a bandwidth exceeding RBCD's capability is important for human auditory system, more work is required. Notice that the 1978 study is still the accepted standard, and is cited as such by the JAES.
Personally, I will go with the more careful of the two studies. If they are able to prove that a higher bandwidth is important, fine. They have not accomplished this yet.
-Chris