Sean, I haven't seen the article in question. Does JA give any explanation for why he thought the SACD's lower HF dynamic range was academic? If the noise is very low to begin with -- as it should be for a player of this caliber (also evident from JA's statement that the player's dynamic range is excellent) -- a 15 dB increase in the SACD noise floor at 20 kHz may not be problematic, much less audible. Again, I haven't seen the graph, but I wonder if this may be what he meant by "academic." What is the baseline noise floor (i.e., what level was the 15 dB increase measured from)? How much dynamic range do you think is needed at 20 kHz to ensure fidelity of a recording? Does the SACD's slightly compressed HF dynamic range approach or exceed your threshold of concern?
The 80 dB rise in the noise out to 70 kHz is of greater concern to me. But here too, if the baseline noise is very low to begin with, even such a large noise increase in the ultrasonic may not be problematic, particularly since most systems greatly attenuate signals above 25 kHz. Then again, in very extended systems, perhaps some of the SACD's ultrasonic noise could get through and be sensed by certain listeners. Do you know if anyone has tried to measure SACD UHF noise from the speakers?
Don't know the answers - just putting out some stream-of-consciousness ramblings to see if we can come to understand the curious and somewhat troubling results you've pointed out. I'd be interested to hear your thoughts, along with everyone else's. Don