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full frequency range recording


Parrot

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With all the posts about new tweeters, and super tweeters, and the rolling off of frequencies on vintage amps, I thought it might be beneficial to point out that the full range of sound we hear is 30Hz to 14KHz. If you want proof, it's right here on the inner sleeve of a London ffrr record. Anything above and below those extremes is wasted.

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Parrot, Let me ask you this; The human ear DOES NOT hear 20HZ, you feel it, not hear it? 20KHz the human ear can't hear that either? The older you are the less you hear on the high end? Basically what you posted is true, and all the talk about a range of 20Hz on the low end, to a range of 20KHz or more is just idle talk? This is my understanding, or am I off base on this? Please give me your opinion on this, although I think you just did.

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I can hear from about 30Hz to 10kHz at 75db SPL (louder than normal conversation) at my sweet listening spot as measured slowly on C scale with Radio Shack analog meter. I am upper-40s. Studies show however that humans can discern a different difference with frequencies as low as 5Hz and as high as 25kHz. Youthful hearing at certain SPLs is very sensitive:

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80dB: 300 to 6kHz

90dB: 100 to 6kHz

100dB: 25 to 6kHz

110dB: 100 to 7kHz

Pretty narrow range huh?[*-)]

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First of all, the fundamental frequencies of all the highest playing natural instruments top out around less than 5000Hz (any only a handfull can get anywhere near that) - everything else on up is overtones and harmonics which help differenciate the overall different sounds of the instruments. Basically you tweeter is for the harmonics.

Some instruments (like cymbals) go up to 90,000Hz! Even if you can't hear the highest sounds, it is important that some of these sounds be present within the signal because they influence the sounds that you do hear (one of the reasons vinly that holds up to 50000Hz sounds different from CDs that hit the wall at 22000Hz.)

Experiments have been performed to demonstrate that people can tell the difference between music reproduction that passes ultra high frequency content from music reproduction that does not - even though they cannot hear it, it changes the way the music sounds.

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Good points pauln. Before anyone claims that there is no way to record 50KHz on vinyl, Quadraphonic sound in theseventies used an FM modulated carrier recorded between 30 and 50 KHz to capture the rear channel information and allow compatability with standard two channel systems.

Rick

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oldbuckster, I think your understanding of the situation is correct. The thing that drives the 20Hz demand is the fake instrument noises on rap "music" and Godzilla stomping around on home theatres.

A useful chart:

http://www.listenhear.co.uk/general_acoustics.htm

Thanx for the chart info, and your answer, my only comment is Rap isn't music!

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oldbuckster, I think your understanding of the situation is correct. The thing that drives the 20Hz demand is the fake instrument noises on rap "music" and Godzilla stomping around on home theatres.

A useful chart:

http://www.listenhear.co.uk/general_acoustics.htm

Thanx for the chart info, and your answer, my only comment is Rap isn't music!

Not for xenophobes!! [:D][;)][:D][;)]

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Well I can hear up to 23kHz...at least that's how high I got on my last

official test a few years ago. But I also have relatively young ears.

I would very much like to see some documentation about LP's playing up

to 50kHz. It's also important to point out that the design limitations

for FM modulation are quite different than for a normal audio signal...

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I know that at 58 years old I don't hear as well as 30, but I think that is normal. Years of factory work before OSHA mandated hearing protection didn't help either. My dad always said that the Rock n Roll will make you deaf, hope he was wrong.

Jacksonbart, There must be 2 Godzilla's, the one from here killed himself after listening to rap music.

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I have seen those labels too Paul - did wonder if it was the genuine opinion of the day or simply as high as they could reliably measure in those days.

I certainly don't hear anything missing from the music on those old Londons at the top end - but as with others my hearing rolls off rather lower that the 20 KHz limit of CD.

Last time I did a frequency sweep on my system I couldn't hear the 16 Khz tone - the only way I knew it was playing at all was the meter in my hand.

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I, too, could once hear out to 23 or more khz. "Ultrasonic" burglar alarms left running (but disconnected to the alarm during the day) at museums and banks were PAINFUL when I would step under one doing a good 140 db!

Also, I concur one of the limits of CD is the 22khz cuttoff compared to LP or live music. I do not know what impact these directly inaudible components have on what we can hear, but they do.

Also, while I don't have documentation, if you can find references to the old JVC/RCA (I think) LP quadraphonic system you will have the proof of LP's going out to 50khz and cartridges made to play them back. Never worked well, as, like CD, that 50khz bandwitdth was split in half with the front channel played normally and the rear channels double in frequency to occupy the rest of the bandwidth, then transcoded back to audible by a decoder.

However, the problems were more in the transcoding and such that with the medium or cartridges.

Dave

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