Frequency Response of L.P's

One method of quadraphonic recording on vinyl involved recording from 20Khz to 40Khz, but this information was Frequency Modulated, using a special preamp to decode it. Because it was FM, flat frequency response and low distortion was not required. (Like FM radio).

Nevertheless, the requirement for some kind of sensitivity up to 40KHz caused large improvements in pickup technology, which has benefited us long after quad vinyl died.

Some audiophile recordings have claimed flat response to 22KHz. This is fairly easy to measure simply by looking at the grooves with a microscope.

Do you think our amps and speakers today can reproduce the 20Khz and below frequency?

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.