Frequency Response of L.P's

Zaikesman...As you say, response to several octive above the highest frequency of interest is an indication of good performance up to that frequency.

When I was in college (many moons ago) I was a subject in some research project relating to hearing, and, as part of this project, my ears were "calibrated". At that time my hearing did extend well beyond 20 KHz, which was the highest frequency of interest to the experiments. Perhaps because of this early experience I have maintained an interest in the subject of human hearing ability.

Over the years the highest frequency pure tone that I can hear has moved steadily down. By now I guess it is around 12 or 14KHz. But, while I cannot hear a 16 KHz tone, I can sense the effect on white noise of a low pass filter at 18 KHz. This is why honest response to 20 KHz is necessary, and why a supertweeter good to 30KHz can be desirable if the source can match this.

Response to 100 KHz is no big deal for an ultrasonic transducer, but it would be a stretch to call it a loudspeaker.

There is the old story of Geoff Emerick the Beatles guy calling Rupert Neve in to suss a fault on a console,that he designed,and Emerick's "golden ears" were not happy with.It turned out that Emerick could hear a fault in 3 panels generated by a 3dB glitch at 54Khz.Some transformers were wired wrongly and he could hear it even though it seemed to be o.k.and people thought he was being fussy.Ultrasonics do effect hearing.stefanl

Stefanl: I'm sorry, but to me that story is likely mostly apocryphal. There were no monitors Emerick could have been using that would reproduce 54KHz flat even if he could hear that high (which I don't believe), and I doubt the response of his board was extended flat beyond that frequency either. If the story has a germ of basis in fact, I would have to assume that whatever was the fault in the board (a ringing spike caused by incipient oscillation? - certainly not a -3dB dip), it must have been precipitating some audible artifacts affecting frequencies down much closer to the range of normal human hearing.

Eldartford: I can understand that smooth ultrasonic extension will aid in maintaining waveform linearity lower in the audioband, and that glitch-free gradual ultrasonic roll-off beginning well above the audioband is probably never a bad quality to cultivate everywhere throughout the recording/reproduction chain (even if a lot of what goes on up there is probably noise). But to me it seems that when it comes time for such a signal to exit a speaker, most conventional designs will be capable of only such limited dispersion that one would have to listen perfectly on-axis with their head in a vise to receive much of the theoretical benefit...

The story about Geoff Emerick is true I have seen 2 Rupert Neve interviews online where he repeats it,and a discussion on a Pro-Audio forum talking about it and how well thought of he is.Anyway in a transcript I have,Mr.Neve talks about his 5106 Console and it goes 5Hz to 150Khz.He says all his designs of this time were of that order.The 5106 being designed by Geoff Watts who worked for Mr.Neve at that time.There is a Neve Webpage and redesigned versions of the early Consoles may be offered.stefanl

Fine as the console may have been, that doesn't answer the monitor question. Again, I don't doubt that there may be a germ of basis in fact for this story, but no matter what Mr. Neve theorizes, I don't believe it's because Mr. Emerick can hear minor response variations *at* 54KHz, even if the audible problem did turn out to be *correlated with* or *caused by* something occurring at that frequecy. Mr. Neve may be in a position to know what the end result of episode was, but IMO can't be certain about the mechanism for its original detection. It makes for a nice story though...