Comments for Vinyl vs. CD - A Running Commentary - Parts 6 - 9 at http://www.hometheaterhifi.com , comment 1 to 62 out of 20 comments http://www.hometheaterhifi.com Fri, 10 Feb 2012 00:51:13 +0100 FeedCreator 1.7.3 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-3905 What about crosstalk? Maybe I've skipped it, but a main thing to consider is the crosstalk between the two channels. With regard to vinyl this is a huge kind of distortion. Crosstalk simply doesn't/can't exist in digital formats. - Jupiter8 Mon, 20 Dec 2010 22:05:43 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-3435 OK. You guys are so far out there on the technical end from my perspective. I read everything posted and understood some of it and the jist of most of it. (I'm a Degreed Mechanical Engineer) I most enjoyed the Sandbox Kicking the most!!! That was amusing!! I liked the posts in the first half that say, "just enjoy it" etc. Here is the deal. I liked to this blog because I am interested in buying a new Stereo. You guys have shown me something different and educational. Let me paraphrase from what I understood so a normal person can understand it. * CD Technology is limited to 16 Bit Resolution/44.1Khz Sampling rate. when an analog recording is recorded on CD, the music is sacrifcied. * Multimedia PC’s can handle uncompressed 24 Bit / 96Khz 7.1 sound. * A good recording is at 96Khz. * Modern Recording are above 100Khz., but have to be compressed to 44.1Khz to be playable on a CD. * SACD and DVD-A are compressed. Soon to be obsolete technology * 7.1Ch lossless Codecs on Blueray is emerging standard. * The recording and engineering make the difference. * Telarc produced some of the best sounding CD’s (feel free to correct or add) I was mostly saddened to hear JEJ state that 450Khz would be the rate to displace analog. It's ok, it just means I have to wait. . . As an outsider looking in; I have a bigger picture than the nitty/gritty technical arguments. This post by C. Weber June 22, 2008 says it all for me. Multi-stereo surround recording and High Resolution Recordings. Call me a Zen, Freak, or tell me to go back in my hole. Whatever. I'm just calling it as I see it from 30,000 feet. To me, this looks like the future, and the technology will come because of what you described. This is where to invest your stereo dollars, or equipment It's where I am headed as a consumer. IMO - Just a Guy Tue, 20 Jul 2010 10:09:32 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-3353 LPs from a good master sounds more real & detailed than the same song from a CD. usign decent analog equipment vs. the best digital equipment. the details are not IMD distortion or Noise. technically its far more complex than just IMD and noise floor. there are many other variables not even considered in the test. - Juan Pablo Cuervo Thu, 24 Jun 2010 07:47:00 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2714 Enrique, you need a graph or machine to tell you the difference? Just use the best instrument we have, your ears! - Piero Wed, 03 Feb 2010 03:06:07 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2710 Now that everybody is listening to MP3 through their iPods, computers, even hi-fi equipment, the whole topic is marginal at best. Perhaps it would be interesting to know how much are we missing by using MP3. - Enrique Tue, 02 Feb 2010 23:08:27 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2442 You asked for a vinyl vs vinyl comparison with the analog vs digital master being the variable. That's not a vinyl vs CD comparison which is why I asked what I asked. It was a question not a pontification. So without complicating things, what's the answer? And this is not engineering 101, it's addition and subtraction. Take the master and the copy, level-match, invert the polarity of either one and mix the two signals. Whatever they have in common gets cancelled, whatever they don't have in common is what's left and it's called distortion plus noise. Since you asked for 20 kHz in the vinyl vs vinyl comparison you might also want to specify whether it's the first play or the 20th, the 50th etc. Maybe 20 kHz according to number of plays can be its own comparison. Wouldn't you find that interesting? - Nick P. Tue, 01 Dec 2009 05:27:01 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2401 to actually see what the vinyl output looks like vs. the digital, since this thread was all about vinyl vs. cd, and not about your tired, unimaginative, repetitive pontification regarding the merits of 16/44 via engineering 101. - JM Thu, 19 Nov 2009 22:31:38 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2391 1. Analog outputs of analog and digital sine wave generators (as master as a master gets) can be compared directly so what would be the point of adding vinyl to each of their outputs? 2. The real test is still this - analog generator feeds A/D/A stage so output of A/D/A can be compared to the source. Measurable difference? Maybe. Audible difference using 10k and 20k sine waves? Good luck. - Nick P. Wed, 18 Nov 2009 06:58:34 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2383 It would be nice if we could see posts of vinyl at 10K and 20K from both an all analog recording, as well as one cut from a digital master. - JM Mon, 16 Nov 2009 20:14:22 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2265 I don't believe the graphs are true representations of the signal before the low-pass filter because the dots were connected with straight lines instead of connecting them using the mathematical formulas described on the Wikipedia page. Specifically the last bullet point under "Mathematical basis for the theorem" which I quoted earlier, with respect to the Dirac comb function. http://en.wikipedia.org/wiki/Nyquist–Shannon_sampling_theorem#Mathematical_basis_for_the_theorem 44.1kHz does not lack the required information for sound reproduction below 22kHz, but you can deconstruct/reconstruct more accurately if your process is performed at a higher sample rate. It is somewhat analogous to performing a chain of multiplication and division operations using decimal places even though your original numbers are integers. By using the decimal places, you help avoid rounding errors. This is mentioned under the "Practical considerations" section of the Wikipedia page. http://en.wikipedia.org/wiki/Nyquist–Shannon_sampling_theorem#Practical_considerations Dan Lavry has a nice paper about this: http://www.lavryengineering.com/documents/Sampling_Theory.pdf - Josuah Thu, 08 Oct 2009 23:33:05 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2258 If you make a statement that you don't believe the graphs are true representations of the signal before filtration, you will have to say why you don't believe it, i.e., provide a link to a mathematical analysis that supports your statement. Otherwise, it is only an unsubstantiated opinion with no basis. Secondly, as to the 44.1 kHz lacking any information for reproduction of frequencies below 22 kHz, you contradict yourself in the next sentence by saying higher sampling rates will allow more accurate reproduction. If it's more accurate, then something was lacking in the lower sampling. And there is no "outside the realm of pure math" with digital sampling. It is all math. - JEJ Wed, 07 Oct 2009 00:40:34 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2256 My main disagreement is with the statement that the graphs you posted are a good representation of the pre-filter signal. I don't believe them to be so, nor do I believe 44.1kHz is fundamentally lacking any information needed to reproduce sounds below 22.05kHz (non-inclusive). I do agree that a higher sampling rate both when recording and playback will allow you to more accurately reproduce the sound, given practical considerations that come into play outside the realm of pure math. That's why modern ADCs and DACs oversample. - Josuah Tue, 06 Oct 2009 10:07:44 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2255 Regardless of the reconstruction algorithms, the graphs show that there is not much information to reconstruct the sinusoidal waveform at high frequencies. It is certainly not perfect. Otherwise, an article on Vinyl vs. CD would not even have been written by anyone, including us. It is because of the imperfect reconstruction that so many consumers don't like the sound. It is, after all, a reconstruction of the analog signal, not a reproduction. The process tries to fill in the blanks, and at high frequencies, the blanks are pretty big with 16/44 sampling. I think that if we were to go to 500 kHz sampling, 24 bit, no filter would be necessary because typical studio microphones don't respond beyond 20 kHz, and some even roll off at 15 kHz. - JEJ Tue, 06 Oct 2009 06:17:18 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2253 Or: "Theoretically, the interpolation formula can be implemented as a low pass filter, whose impulse response is sinc(t/T) and whose input is [a Dirac comb function modulated by the signal samples]." Either way, the input into the low pass filter is not just the samples with straight lines connecting them. - Josuah Mon, 05 Oct 2009 07:12:28 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2251 You're not supposed to draw straight lines between the samples. Even if you are trying to show the result before the low-pass "analog reconstruction" filter. See "The Procedure" section under: http://en.wikipedia.org/wiki/Nyquist–Shannon_sampling_theorem#The_sampling_process The reconstruction filter is to remove aliasing artifacts. Not to make the curve "curvy" instead of "straighty". - Josuah Mon, 05 Oct 2009 07:01:52 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2250 Use Cool Edit Pro or its Adobe successors. Even though the dots riding on the signal have a ridiculously different pattern, especially at high frequencies, that's how PCM works and the low-pass filter is key. If anyone wants to talk about how things change as signal frequency approaches half the sampling rate, even while ignoring an invention called oversampling, first look through the same glass at what happens when the same signal is cut to vinyl and played (one of the reasons that discrete quadrophonic had no chance). Speaking of vinyl loving rituals, a must-see: the Everybody Loves Raymond episode where he gets his 50s-jazz-vinyl-loving dad a CD player for Christmas. - Nick P. Mon, 05 Oct 2009 03:02:33 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2249 You mentioned flipping to side 2 as a limitation. With my set of classic jazz LPs, remastered at 45 RPM, I have to flip to side 2, then a second LP for side 3, and then to side 4. Each album is two LPs because of the increased tracking velocity (45 RPM instead of 33-1/3 RPM). Each side plays for about 10 to 15 minutes. - JEJ Mon, 05 Oct 2009 01:54:00 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2248 One has but to listen to a Beethoven symphonies on LP to hear the dynamic limitations of vinyl. And the ability of a CD to play an entire symphony with out "flipping" to side two is not just convenient, but essential! - JM Mon, 05 Oct 2009 00:08:05 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2239 A Couple of Points said - And JEJ, it's really quite misleading to show DAC output before reconstruction filtering had done its job. NO ONE hears the sine waves shown above. - It's not misleading. You just scanned the paragraphs too quickly. I specifically mentioned in paragraph 5 - The lines connecting the dots represent the signal that is fed to the output stage before any filters are applied. - and - The filter's job is to make these jagged lines more sinusoidal, so that it will be like the music that was recorded, which is also sinusoidal. The point of the discussion is to show how difficult a job the filters have with conventional Redbook CD encoding, and that even with 24/192, the 20 kHz region, which is on average, the limit of human hearing, the unfiltered waveform is not smooth. A few years ago, an engineer tested various sampling frequencies and listened for improvements in the reproduced sound with higher and higher sampling rates. He stated that it was at about 450 kHz that the limit of audible improvement was reached. I am beginning to think he might be right. - JEJ Sun, 04 Oct 2009 01:58:21 +0100 http://www.hometheaterhifi.com/technical-articles/427-a-secrets-technical-article.html#comment-2238 Not voting one way or another, but I think many of the vinyl lovers enjoy the rituals associated with it. - the careful disrobing of the record - the de-staticing and dusting - the gentle lowering of the cartridge - the tweaking After all that work, of course it's going to sound good. :-) PS For the record (no pun) I wish I had a lot of 50s era jazz classics on vinyl. - ws Sat, 03 Oct 2009 21:22:39 +0100