Frequency Response of L.P's

Amps...no problem. Many speakers roll off by a few dB at 20KHz. Some supertweeters are good to 30Kc and higher. "Ultrasonic" transducers go much higher, but noone (except bats) cares about sonic fidelity at these frequencies.

Why then, (a little unrelated) does the Avalon Eidelon Diamond series speaker boast a supertweeter that goes to 100Khz? The 'regular' Eidelon goes up to about 40Khz.

How high is the regular CD player capable of ??...... vs a phono cartridge??

How high can we hear?

JB: The presumed advantage of that diamond tweeter would have to include its performance in the audible range, not just its allegedly greater extension. The exact Hz figures I'm guessing are mostly 'specsmanship'. One of the real benefits of designing a tweeter diaphragm with the highest possible rigidity-to-mass ratio is the potential to move its fundamental resonance frequency out as far above the audioband as possible (allowing it to act most like a pure piston within the audioband), and I assume that's the reason for the "diamond" construction. There's nothing of musical value going on at 100KHz anyway, even if the software could capture it, the rest of the system could transmit it, and we could hear it (we can't). A CD and its player can only capture and transmit information up to between 20KHz and 22KHz due to the Red Book sampling frequency standard, but it's generally thought that the audioband side effects of the steep filtering above that frequency limit - rather than the loss of any higher frequencies per se - is mostly to blame for any audible artifacts that degrade CD HF reproduction. Human hearing is nominally considered to extend to 20KHz max., but while a few individuals (probably mostly young, and maybe mostly female) may be able to hear up to a somewhat higher frequency limit, most of us adult males actually get by with hearing response that begins rolling-off well before those heights, maybe between 12KHz and 16KHz, and a lot of us are completely deaf to info above 16KHz-18KHz or even lower.

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