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For you smart audiophiles...
wrote in message ... On Fri, 28 Dec 2007 10:04:55 -0500, "D.Duck" wrote: "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. The windings on the yokes were a major source of high frequency noise. That too. |
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