IDM Mailing Archive

quoted 15 lines In a message from Matt:

> > In a message from Matt: > > >even though the human ear can only > >acknowledge sound waves of less than > >20 kHz (and presumably there is a similar > >limit for low frequencies), > >is this a valid reason to remove > >the frequencies outside these limits > >for sound reproduction. > > There is in fact a lower limit, it's generally reckoned to be 20Hz. You don't hear > people saying that you shouldn't record below 20Hz, you can in fact get sub woofers > which play nothing but these lower frequencies. Why on earth would you want to get rid > of the higher frequencies?

The human hearing has a frequency range of 20hz - 20khz. Young children have a much greater range. Humans cannot hear lower frequencies, sub-woofers only allow you to feel lower frequencies. In fact, it is possible that I made a mistake above. I think it is a limit of 50hz as the lowest frequency limit. As an example the human liver resonates at around 2-3 hz or is it 2-3khz. Cheers, Mike -- +------------------------------------------------------------------------+ | Michael Keay, Software Engineer VMark Software Ltd. | | E-Mail: mkeay@vmark.co.uk Power House, Davy Avenue, | | Tel : (01908) 234990 ext. 221 Knowlhill, Milton Keynes, | | MK5 8HJ, UK | +------------------------------------------------------------------------+

In message from Mike:

quoted 3 lines The human hearing has a frequency range of 20hz - 20khz. Young children

>The human hearing has a frequency range of 20hz - 20khz. Young children >have a much greater range. Humans cannot hear lower frequencies, >sub-woofers only allow you to feel lower frequencies.

Why would you want to exclude higher frequencies, I'm sure you could sense them is some way. Lots of love Tim One of the least common things in the world today is: common sense.

Tim said:

quoted 8 lines In message from Mike:

>In message from Mike: > >>The human hearing has a frequency range of 20hz - 20khz. Young children >>have a much greater range. Humans cannot hear lower frequencies, >>sub-woofers only allow you to feel lower frequencies. > >Why would you want to exclude higher frequencies, I'm sure you could >sense them is some way.

You could? The only senses left would be sight (can't see it), smell (can't smell them), taste (puhleeze), and touch. Unless someone can prove that you can feel frequencies above 20khz (I doubt it)..... ------------------------------------------------------------ | Bob Weisend | "I'm not an actor, | | rweisend@oboe.aix.calpoly.edu | but I play one | | http://www.calpoly.edu/~rweisend | on TV." | ------------------------------------------------------------

The human hearing range is not restricted to between 20hz -20khz. Everyone has a different hearing range, in fact Goodmans ran a speaker campaign based on the fact that women tested the speakers because women commonly have a greater hearing range than men. Sub woofers produce sound that you can hear and lower frequencies that you can feel. They are designed to produce bass when your main speakers can't get any lower. Sub woofers from REL have adjustable characteristics to allow them to act as an extension to your speakers. When Phillips started doing demos for DCC they claimed that the compression used removed sounds that you could not hear either frequency cut off or removing quiet sounds in loud passages. The only problem was that a lot of people could hear that the higher frequencies had been cut off and could hear the quiet sounds in the loud passages and noticed when they were removed. Some companys are know producing CD players which add very high frequency sounds which are beyond the range of the CD recording frequency range. Legato- link is an example. Can you hear a faint very high frequency sound when watching the TV? Many people can but is supposed to be above the human hearing range.

Going a little off-topic I think, but I couldn't resist to notice following:

quoted 2 lines The human hearing range is not restricted to between 20hz -20khz. Everyone

> The human hearing range is not restricted to between 20hz -20khz. Everyone > has a different hearing range

Correct..

quoted 2 lines Can you hear a faint very high frequency sound when watching the TV? Many

> Can you hear a faint very high frequency sound when watching the TV? Many > people can but is supposed to be above the human hearing range.

The frequency you're talking about is the line-frequency (horizontal) of the TV, and that's 15.625 kc so that's why most people can hear it. But because it's very weak, it's not irritating. I can always hear if there's a TV switched on when entering someones home :-) Cya! Timo ___ timoh@ultraworld.xs4all.nl ____| We have not scratched the surface |____ | of what the mind can do.. |

quoted 1 line The human hearing has a frequency range of 20hz - 20khz.

>>The human hearing has a frequency range of 20hz - 20khz.

This is a VERY general measure. Quantifying the lower range is problematic - it's hard to judge exactly what frequency is felt instead of being perceived in the ear. The upper end varies depending on everything from ear structure to how many SpeedMetal shows you've endured. Some people can't hear above 12kHz (victims of severe hearing loss), others can hear up to 25kHz (part dog, maybe?).

quoted 2 lines Young children

>>Young children >>have a much greater range.

And rednecks w/ guns have a much smaller range.

quoted 2 lines Humans cannot hear lower frequencies,

>>Humans cannot hear lower frequencies, >>sub-woofers only allow you to feel lower frequencies.

Just remember that Women Respond to BASS!

quoted 2 lines Why would you want to exclude higher frequencies, I'm sure you could

>Why would you want to exclude higher frequencies, I'm sure you could >sense them is some way.

quoted 3 lines You could? The only senses left would be sight (can't see it), smell

>You could? The only senses left would be sight (can't see it), smell >(can't smell them), taste (puhleeze), and touch. Unless someone can >prove that you can feel frequencies above 20khz (I doubt it).....

It's pretty easy to prove, actually. Most people can hear a 12kHz tone, right? So, all you have to do is listen to a Sine Wave at 12kHz, then a Triangle Wave of the same frequency. Hear a difference? Most people can. Why is this? If humans could't feel frequencies above 20kHz, then you couldn't hear the harmonics of the Triangle Wave, which are above 20kHz. Filter out the harmonics above 20kHz & you have a Sine Wave. Many acoustic instruments, and SOME analogue synthesizers, produce sound way past 20kHz. Brass instruments especially, tend to have significant energy up to 50kHz. So, listening to a CD can be a bit lacking. Don't worry, the analogue tape that most old music is recorded on is lacking in high frequencies too. Pioneer has just released a 96kHz DAT deck (frequency response to 48kHz). Look for Sony & Phillips to come out w/ some sort of "Enhanced" CD in the next few years so they can sell idiots yet another copy of "Led Zep IV". chill