supposed hearing limit of 20khz is b.s., just saying

[james0tucson]

This shit really isn't up for debate.

The last time I heard that was on an extremely late night Cable Access program about the existence of UFOs. If you don't allow your premise to be debated, you haven't made your case.

[camsr]

http://www.amazon.com/Master-Handbook-A ... 0071360972

This book covers a few basics on the human ear and our hearing mechanism. I suggest you read it to learn the basics before making biased hypotheses on how the world works. Static tones are always louder and more easily perceived. And the Equal Loudness contour is based on the perception of static tones. These days, engineers use noise because the material is multi-octave. The point is that we only receive so many frequencies for a given power level, and the static tone is king. It will be heard, but is not relevant to music. Try analyzing noise centered around 25.1 khz and measure the power, as this would be far more interesting.

[spaceman]

Let's not spoil this thread with meaningful facts people.

[flynsk]

Let's talk about how infrasound at 18Hz makes people see ghosts. That's more fun. SCIENCE!

[spaceman]

Let's talk about how sheep bladders can be used to prevent earthquakes.

[Ford Prefect]

Let's talk about how sheep bladders can be used to prevent earthquakes.

screw the quakes...how many sheep fit in one o' them bladders?

[rifftrax]

Besides, what's to argue? The thread title refers to a "supposed" limit on hearing but no qualified person I know has ever "supposed" that to be the case.

"The ear is an amazing body part because it enables humans and animals to hear what goes on around them. Hearing is one of the five senses of the body. The ears help the body to pick up sound waves and vibrations. Sound travels in waves through the air, the ground, and various other substances. Sound cannot be seen, but it can be felt by vibrations.

The number of vibrations that are produced per second is called frequency. Frequency varies for each sound and is measured in hertz. One hertz is equal to one vibration per second. A sound with a low frequency will have a low pitch, such as a human's heartbeat. A sound with a high frequency will have a high pitch, such as a dog whistle. Humans cannot hear sounds of every frequency. The range of hearing for a healthy young person is 20 to 20,000 hertz. The hearing range of humans gets worse with age. People lose the ability to hear sounds of high frequency as they get older. The highest frequency that a normal middle-aged adult can hear is only 12-14 kilohertz. Also, the hearing range for men worsens more quickly than the hearing range for women. This means that women will have the ability to hear notes of higher pitch than men of the same age do."

- Christopher D'Ambrose -- 2003

"Experiments have shown that a healthy young person hears all sound frequencies from approximately 20 to 20,000 hertz."

- Cutnell, John D. and Kenneth W. Johnson. Physics. 4th ed. New York: Wiley, 1998: 466

"The maximum range of human hearing includes sound frequencies from about 15 to about 18,000 waves, or cycles, per second."

- "Ear". Microsoft Encarta Encyclopedia. CD-ROM. 2000

"The full range of human hearing extends from 20 to 20,000 hertz."

- Caldarelli, David D. and Ruth S. Campanella. Ear. World Book Online Americas Edition. 26 May 2003

"The human ear has receptors that can detect sound frequencies raging from 16 vibrations to20,000 vibrations per second."

- Sebastian Haskel and David Sygoda. Biology, A contemporary Approach. New York: Amsco, 1996

"The maximum range of human hearing includes sound frequencies from 15 to about 18,000 waves,or cycles, per second."

- Lerder, Francis C. "The Human Ear." Encarta Encyclopedia Deluxe 2004. CD-ROM

"Hearing or audition is the sense of sound perception and results from tiny hair fibres in the inner ear detecting the motion of atmospheric particles within (at best) a range of 20 to 20000 Hz. Sound can also be detected as vibration by tactition. Lower and higher frequencies than can be heard are detected this way only."

- Sense. Wikipedia. 2004

"The ear can hear sounds ranging from 20Hz to 20kHz"

- http://www.kemt.fei.tuke.sk/Predmety/KE ... aring.html

Needless to say, these people all seem to think that there is a limit and that it occurs at 20khz or below. I could keep going if you like. It's entirely possible that every single last one of them is "unqualified" but that certainly would be a suspect conclusion to arrive at.

[Meffy]

Those all appear to be approximations for the popular market, not scientific statements. Most of them don't speak in terms of limits but the expected passband. World Book is targeted toward junior high school-level readers. Encarta? :-} I used to keep a list of howlers extracted from its virtual pages.

If you want to demonstrate that your thesis holds water, you'll get onto those measurements. Without those you have no data and nothing to discuss past speculation. Speculation's okay to discuss but not much depth there.

[kx.001]

I always thought it was used as it was handy for the logarithmic nature of dB.

[camsr]

passband.

Shame on all these decent publications not specifying this. But you got it right. What is much more interesting, is the slope or descent of perception as frequency rises. There is no brickwall filter built into your brain, sorry.

rifftrax, you have the test equipment. Why not do some experiments at a safe SPL and tell us how noise at these frequencies is perceived? For equal power from noise through to static tone, the perception should vary considerably.

[Meffy]

Why not do some experiments at a safe SPL

YES! I should've emphasized that before when suggesting doing the tests. Hearing damage is nothing to sniff at.

[Doug1978]

In the end of the day, we're all just numbers.

[Meffy]

*matrix dripping green text effect*

[nineofkings]

Hey guys, I just ran a 4 minute mile. Prove me wrong.

[whyterabbyt]

Hey guys, I just ran a 4 minute mile. Prove me wrong.

metric minutes or imperial minutes?