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In Reply to: RE: The masters used are frequently different posted by rick_m on July 10, 2012 at 15:17:20
Tony Lauck would throw up at hearing about your experience.
My CBS CD1 test disc has a reference 1k level that is 0.2 dB over and unless I backoff, the sine wave has a flat top!
Follow Ups:
No, fmak. In those days, I threw up when listening to CDs. And it was obvious with my two box Proceed player that bits weren't just bits as the fiber optic cable did not sound as good as the coax.
It is not possible for a CD to have a reference level that is over 0dBfs. There is simply no way to encode such a number. If you are getting a flat top it is either because the test track isn't a sine wave or because something is not working properly in your equipment, i.e. you are getting digital or analog clipping somewhere.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
I am telling you that the analog output of CD1 on some reference tracks exceeded the CD 0dB standard and are clipped. I actually measured the distorion thru a very high quality (almost textbook) dac.
According to what you said, there cannot be 'hot' CDs, which is not what happens in practice.
Rip the test disk and examine the samples numerically. You will find that no sample deviates from the allowed range of -32768 to +32767, inclusive. Therefore this test disk is a legal CD. A DAC should play it undistorted. If a DAC can not play it, it is a DAC problem. The most likely cause is limiting in the output of a digital filter. That this happens is evidence that the DAC designer was more interested in good numbers on a spec sheet rather than good sound. By sacrificing less than 1 dB of signal to noise ratio this problem could have been avoided.
Your comment about "hot" CDs is something else. In most cases idiot producers, engineers, and/or musicians are deliberately distorting their "music" with compression and even clipping in the hopes of selling copies to idiot customers who have never heard of a volume control. None of these CDs are too hot, they are just poor. When played on a good system they will sound the same as they did when played in the mastering studio.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Well, I have to admit that my friend's expensive high res digital system IS impressive. He made digital high res copies of some of my vinyl records, and I was hard pressed to tell the difference. In the end, there was a slight difference, but I was SHOCKED at how good his copies sounded. Only a few of my friends can tell the difference between my vinyl records and my friend's digital copies. Of course, this is a great sign for the future of the high end. Progress is sometimes slow and uncertain, but, sometimes, it does occur.
Do you know what ADC and DAC your friend used? Do you know the hires digital format used? It would also be helpful to have know the rest of the system to put the comparisons in perspective.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
It's always a dac problem to you.
It was not only this dac, which is one of the best, but others as well. Rip it, do a fft analysis on any decent editor, and the distortion harmonics are there. The level is over the 0dB reference line. That is the proof of the pudding.
> > The level is over the 0dB reference line. < <
Can't be, something must be measuring an incorrect level because digital doesn't work beyond 0db!
I've recorded many LPs to digital, and I've clipped signals on numerous occasions. This is readily evident when measuring the results/levels ... numerically ... and NOT ONCE did I get a reading OVER 0db ... hence the "clipping".
You might want to share the data files for others to measure.
tb1
Show me the data. You can not do this. You are blowing smoke.Show me a single sample on the disk that is larger than +32767 or smaller than -32768. You can't. Such numbers do not correspond to any possible pattern of pits on the disk. What you describe is no more possible than a five digit odometer on an automobile showing a milage larger than 99,999. There is no magic here whatsoever. Every single bit on the disk can be identified and quantified using a microscope. It isn't even necessary to use a computer to demonstrate this point, but one will need to be a consummate "squint" to examine more than a tiny part of the disk. A competent engineer armed with a microscope and a copy of the Red book specification can do this. I doubt that you have ever read the red book specification or looked at an actual CD under a microscope.
I can take a 1 kHz sine wave in 44/16 format (dithered) and the spectrum shows a single peak, with noise at -128 dB. There are no harmonics. I can resample this to 176.4/16 and look at the spectra. Again no harmonics and the noise is at roughly the same level. If I play this test tone through my speakers there is no distortion at any volume level that I can stand. My system is not broken.
I don't know where you get these DACs that are "the best". If they can't play a simple test tone without distortion they are audiophool equipment.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Edits: 07/11/12
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