"JG2U" wrote in message
...
On Fri, 28 Dec 2007 05:47:59 +0000, Larry wrote:

"Del Cecchi" wrote in
:

And isn't that 44k Bytes per second?

Oh, sorry....44.1K 16-bit SAMPLES per second. Bytes are 8 bit. Here, a
little background reality:
http://www.repairfaq.org/REPAIR/F_cdfaqb.html

Frequency response: 5 to 20,000 Hz +/- 3 dB.
Harmonic distortion: .008 % at 1 KHz.
Dynamic range: Greater than 90 dB.
Signal to noise ratio: Greater than 85 dB.

The frequency response is a dirty lie. That's the DISK frequency
response. If they want to SELL the music on FM radio, they use the RIAA
equalization standard of 50-15000 Hz....which is exactly the audio
bandwidth allowed on FM radio since World War 2 and what's been recorded
on all 33 RPM LPs since the first one was pressed. All the music you
listen to is recorded for FM transmission. Notice the freq response is
+/- 3%, not .3 or .03 or .00001. This means nothing because the worst
instrument in the listening string is YOU and your rotten human frequency
response. Drop by an audiologist and have your own hearing swept
frequency tested. It's just awful, even if you are 16 and never used
hiphop headphones so loud they could hear you in the next car.

Larry

A couple of corrections...

Nyquist's Theorum says that you must sample audio at a rate of at
least two times the highest frequency you want to recover, our else
aliasing (distortion) will occur. So 20,000 hz times 2 = 40,000. So,
the 44,100 samples per second rate allows up to 20,000 hz to be
recorded and played back. While it's true that most pop music is
recorded with a mix that will sound good on FM radio, the frequency
response on those recordings are not necessarily limited to 15kHz. The
FM transmission by its nature just rolls off anything above 15k in the
source material.

Also, the frequency response is +/- 3dB, not %. 3dB is about the
minimum volume change the human ear can detect in a complex audio
waveform (such as music). While the human ear does not have a flat
frequency response by any means, it CAN detect any changes from the
response curve it is used to hearing. Crank up your bass and treble
control to see what I mean.

What that means is that when you hear the playback of a particular
musical instrument through your sound system, you hear not only the
instrument, but also whatever was added and/or subtracted by the
recording and playback equipment. The less the equipment changes the
sound, the better and more accurate the instrument sounds compared to
the original source. That's why those specification numbers have to
be so good... your ear can hear the coloration that a limited or a
non-flat flat frequency response adds to the source. Even if the
sound is slightly outside of your audible hearing range, studies have
shown that those sounds still contribute to what your brain perceives.

Oh, and TVs don't whine anymore because they figured out ways to
mannufacture them so they are quieter. When one gets noisy I can
still hear it.

This biggest single contributor to the horizontal scanning frequency noise
came for a poorly constructed flyback transformer.