Xref: utzoo sci.electronics:10693 rec.video:11181 Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!zaphod.mps.ohio-state.edu!rpi!uupsi!rodan!amichiel From: amichiel@rodan.acs.syr.edu (Allen J Michielsen) Newsgroups: sci.electronics,rec.video Subject: Re: CD's and digital audio (was Why I hate CDs) Message-ID: <2486@rodan.acs.syr.edu> Date: 19 Mar 90 05:31:43 GMT References: <1554@redsox.bsw.com> <38844@iuvax.cs.indiana.edu> Reply-To: amichiel@rodan.acs.syr.edu (Allen J Michielsen) Organization: Syracuse University, Syracuse, NY Lines: 71 >In article <1554@redsox.bsw.com> campbell@redsox.bsw.com (Larry Campbell) writ >>In article bas+@andrew.cmu.edu (Bruce... >>-The analogy with audio is that a CD with frequency response out to 10 >>-MHz would not sound better than one with frequency response out to 20 >>-KHz, because the human ear can't hear the higher frequencies. >> >>Speak for yourself. Perhaps the *average* human ear can't hear higher >>than 20 KHz, but some can. I don't know what frequency they are, but >>CDs would have been nice if they had a decent high frequency rolloff; but if >>I A/B an LP and a CD it is clear that the CD has cut off the higher >>frequencies. >> >>Anyone know if DAT will have a better high end than CDs (presumably this >>depends almost entirely on its sampling rate)? 1. If you were to do a FFT or detailed signal analysis of LP's VS CD's you would discover that LP's may/can/do sound 'brighter' in some circumstances. a. The 'label' re-eq'ed the lp pseudo master to create a cd master. (This is the worst, & especially a problem with older stuff that the un-mixed masters are a memory, especially from smaller labels.) b. The extra LP high frequency 'response' is noise. It is nearly random and is/was (usually) NOT intended as a part of the audio program. (some high end cd players allow you to add desired pseudo noise to recreate this effect, they add a funny name but all they do is create frequency modulated noise using the actual signal as a base freq multip. 2. Human freq response is typically about 22Khz for 30Db roll off for a 20 year old male. This average changes to about 20Khz & 40Db by age 40. I can still personally hear out to 24Khz at 20Db, but also can hear it dropping over the last several years. I quite sure that human recorded max was 28Khz & 15 Db. Usually what we hear loudly from ultra sonic devices are harmonics, USUALLY. 3. If you think CD's are bad, DAT has a 45DB NOTCH cut in it at 15KHZ, that is about 1K wide above 3DB. I find this offensive cut worse than anything cd's could do. Besides, as in 1a 1b, they will sound the same because the lp noise isn;t there, & the bad eq's stuff should be all gone by the time it really hits these shores, but don't count on either. 4. If the cd's sound so bad for top freq, you could also be hearing a junk cd player. 5. If played a analog or digital, digitizing ratethat of cd or above, & given pictures of 3 waveforms, which you are listening to: The waveform type is listened to & 'taught' at a low freq, 10K or below. Then again at 18 or 20 & amplified to correct for tested subject rolloff, the resulting type selection rolls off from a average around 95% to 5%. Basically random chance. Therefore, audibly; the method by which CD's recreate higher frequency waveforms, does not make any measurable difference. I agree, the sampling rate should have been higher & given today technology would/could be. But, consider the following, if the same were said of LP technology, we would just be switching from 78's to laser read 8" analog 100 minute disks. Can you imagine your or any real stereo today, which 78's are just ending as the 'standard' media ? A standard media (any) has to make tradeoffs for the current affordable technology when the standard 'goes public'. It also has to make tradeoffs that can be sold to the market, packaged,..... Further, I believe that amyone that thinks lp's as a 'standard' will outlast CD's is in a dream world. DAT isn't the thing that will do it, and TOO much money has been gambled on it for something else to come along in time to kill of cd's soon, (IF even that is possible now, but.....). DAT's are one sided, so rewinding will return as a major Pain in the A. Then we consider tape damage & wear. Up north & down south temperature is a major source of tape death in the car. I would never consider putting a 12-15 $ abrasive original in such a environment. Then we consider getting dubbing decks for DAT's & the installed cassette car base. I believe that recording CD's will stamp out any chance that DAT may have, even for the audiofile. For most of us, DBX, dolby C, & metal tape would be sufficient. Too bad the early DBX system flaw(s) weren't fixed & accepted by the public at large. al