marce Posted February 6, 2018 Share Posted February 6, 2018 On 05/02/2018 at 6:34 AM, sandyk said: What is exported from the USB Port to the DAC is an ANALOGUE representation of the digital data, and subject to the usual analogue vagaries due to the length of the cable, the isolation between D+and D-, and +5V Vbus and 0 volts, correct impedance of the USB cable, noise on the PC's internal +5V USB supply etc. Some longer USB cables don't even have shields, presumably done deliberately to extend the operating distance of the cable !!! https://www.audiostream.com/content/draft?page=1 http://www.audiostream.com/content/theres-no-such-thing-digital-conversation-charles-hansen-gordon-rankin-and-steve-silberman-p http://www.audiostream.com/content/qa-john-swenson-part-1-what-digital http://www.audiostream.com/content/qa-john-swenson-part-2-are-bits-just-bits https://www.audiostream.com/content/qa-john-swenson-part-3-how-bit-perfect-software-can-affect-sound Nope its digital, digital signals and digital engineering... Yes we know a digital signal is made up of a fundamental sine with many harmonics added, the number dependant on the rise time. Other than that its digital and so the signals are not affected the same way analogue signals are, that why we look at info by the likes of Howard Johnson etc. An eye diagram also shows us the effects of a cable on the wave as well as many other things. The main difference is unlike an analogue signal noise is not added to the information. For information regarding this thread, look up EMC/Signal Integrity, thats basically what it is about. Henry Ott, Ralph Morrison and Keith Armstrong are a good source for EMC, Howard Johnson, Eric Bogatin for signal integrity jabbr 1 Link to comment
Spacehound Posted February 6, 2018 Share Posted February 6, 2018 2 minutes ago, sandyk said: The attached is more like what is received at the DAC ! From : https://www.rs-online.com/designspark/raspberry-pi-waveforms Read the line directly above the photo again. Link to comment
marce Posted February 6, 2018 Share Posted February 6, 2018 23 hours ago, One and a half said: So are these references worthless? Footnote 1For those who are truly interested in diving in deeper... High Speed Digital Design: A Handbook of Black Magic Howard Johnson, Martin Graham, 1993 High Speed Signal Propagation: Advanced Black Magic Howard Johnson, 2003 Electromagnetic Compatibility Engineering Henry W. Ott, 2009 EMC for Product Designers, Fourth Edition Tim Williams, 2007 Grounding and Shielding: Circuits and Interference Ralph Morrison, 2007 Digital Circuit Boards: Mach 1 GHz Ralph Morrison, 2012 Solving Interference Problems in Electronics Ralph Morrison, 1995 Noise and Other Interfering Signals Ralph Morrison, 1991 Read more at https://www.audiostream.com/content/theres-no-such-thing-digital-conversation-charles-hansen-gordon-rankin-and-steve-silberman-p#RSUrc61YKh1Tmc9z.99 Standard design office documentation.Read some of them and you'll understand digital signal propagation and its associated problems, not the same problems as analogue or say microwave. Link to comment
sandyk Posted February 6, 2018 Share Posted February 6, 2018 24 minutes ago, marce said: Nope its digital, digital signals and digital engineering... Yes we know a digital signal is made up of a fundamental sine with many harmonics added, the number dependant on the rise time. Other than that its digital and so the signals are not affected the same way analogue signals are, that why we look at info by the likes of Howard Johnson etc. An eye diagram also shows us the effects of a cable on the wave as well as many other things. The main difference is unlike an analogue signal noise is not added to the information. For information regarding this thread, look up EMC/Signal Integrity, thats basically what it is about. Henry Ott, Ralph Morrison and Keith Armstrong are a good source for EMC, Howard Johnson, Eric Bogatin for signal integrity Many people agree that it is an analogue representation of the digital signal that is exported from the USB port. Spacehound agreed with that several posts back. " While I agree about it being analogue, it's a representation, as you say. It's not somethin that you have to amplify or whatever accurately. " I would suggest that you look at the links I provided earlier in this thread, especially this one, followed by those that Garry posted. https://www.audiostream.com/content/theres-no-such-thing-digital-conversation-charles-hansen-gordon-rankin-and-steve-silberman-p " Any degradation of the digital waveform will have consequences, and when that waveform is degraded, there is no way to restore it properly. Once the fine detail is lost, it is lost forever. - C.H." How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file. PROFILE UPDATED 13-11-2020 Link to comment
adamdea Posted February 6, 2018 Share Posted February 6, 2018 1 hour ago, marce said: Standard design office documentation.Read some of them and you'll understand digital signal propagation and its associated problems, not the same problems as analogue or say microwave. Anyone interested in actually thinking about this subject might wish to start by asking themselves what the title was of the paper in which Shannon proved the sampling therorem, and why. No really. http://nms.csail.mit.edu/spinal/shannonpaper.pdf You are not a sound quality measurement device Link to comment
Popular Post Spacehound Posted February 6, 2018 Popular Post Share Posted February 6, 2018 1 hour ago, sandyk said: Many people agree that it is an analogue representation of the digital signal that is exported from the USB port. Spacehound agreed with that several posts back. " While I agree about it being analogue, it's a representation, as you say. It's not somethin that you have to amplify or whatever accurately. " I would suggest that you look at the links I provided earlier in this thread, especially this one, followed by those that Garry posted. https://www.audiostream.com/content/theres-no-such-thing-digital-conversation-charles-hansen-gordon-rankin-and-steve-silberman-p " Any degradation of the digital waveform will have consequences, and when that waveform is degraded, there is no way to restore it properly. Once the fine detail is lost, it is lost forever. - C.H." I will return, briefly. "Any degradation of the digital waveform will have consequences, and when that waveform is degraded, there is no way to restore it properly. Once the fine detail is lost, it is lost forever. - C.H." That's bollox. 'Digital' transmission is DESIGNED to be immune to a considerable amount of degradation. It's why the system is deliberately designed so that the levels and waveforms aren't critical. Don't believe me? Ask IBM or any manufacturer of modern airplane control systems. (Real airplanes, don't confuse them with my comment below.) What is more, you can buy digital systems where the signal transmission level is below the universe's background 'hiss' level and they work perfectly even in a high noise environment. In any model airplane shop. That's yer lot from me. esldude and marce 1 1 Link to comment
marce Posted February 6, 2018 Share Posted February 6, 2018 1 hour ago, sandyk said: Many people agree that it is an analogue representation of the digital signal that is exported from the USB port. Spacehound agreed with that several posts back. " While I agree about it being analogue, it's a representation, as you say. It's not somethin that you have to amplify or whatever accurately. " I would suggest that you look at the links I provided earlier in this thread, especially this one, followed by those that Garry posted. https://www.audiostream.com/content/theres-no-such-thing-digital-conversation-charles-hansen-gordon-rankin-and-steve-silberman-p " Any degradation of the digital waveform will have consequences, and when that waveform is degraded, there is no way to restore it properly. Once the fine detail is lost, it is lost forever. - C.H." That quote is pointless and means nothing, what fine detail... if it were an analogue signal it would have a meaning as it is it means nothing. The waveform is degraded by signal transmission, NONE of the information being carried by the digital signal is lost by that degrading of the digital signal, usually some rounding off of the edges. Like the rest of the article is a bit of fluff put out for the true believers, not a lot of content its a magazine interview not a white paper. esldude 1 Link to comment
marce Posted February 6, 2018 Share Posted February 6, 2018 27 minutes ago, adamdea said: Anyone interested in actually thinking about this subject might wish to start by asking themselves what the title was of the paper in which Shannon proved the sampling therorem, and why. No really. http://nms.csail.mit.edu/spinal/shannonpaper.pdf Why pick on me... I am quite au fait with signal transmission and the issues involved. Whilst a relevent paper, far too heavy on the maths rather than the practical side. Link to comment
Popular Post adamdea Posted February 6, 2018 Popular Post Share Posted February 6, 2018 Just now, marce said: Why pick on me... I am quite au fait with signal transmission and the issues involved. Whilst a relevent paper, far too heavy on the maths rather than the practical side. Not picking on you! Sorry that wasn't what I meant. I think it rather supports your point. Signal integrity in the presence of noise is what digital transmission is about. It's what its for. All this rfi guff and "digital is analogue" nonsense is a way of programming people to think backwards. esldude and Spacehound 2 You are not a sound quality measurement device Link to comment
marce Posted February 6, 2018 Share Posted February 6, 2018 I see Spacehound was rather more succinct in his appraisal of the comment than I was. Just to add more... The big problem as things got faster was twofold; one there was no way to measure and assure high speed links, and two most of the corners were square or 45 degrees which results in reflections and degradation of the signals. Wrong regarding corners look at…http://www.sigcon.com/Pubs/edn/bigbadbend.htm As said its an article aimed at a particular audience and biased heavily towards their beliefs... Link to comment
marce Posted February 6, 2018 Share Posted February 6, 2018 2 minutes ago, adamdea said: Not picking on you! Sorry that wasn't what I meant. I think it rather supports your point. Signal integrity in the presence of noise is what digital transmission is about. It's what its for. All this rfi guff and "digital is analogue" nonsense is a way of programming people to think backwards. As said it is a relevant paper but something simpler on BER or similar would be more illustrative of the point, someone did put up some figures and to be honest its a non issue these days in most instances... They would moan if we still controlled stuff using 4-20ma loops etc. LOL but then maybe it was better because is was analogue.... Link to comment
marce Posted February 6, 2018 Share Posted February 6, 2018 One thought, looking for EMC using a tuned circuit with an antenna will show you its presence, what it wont show you is how much will be picked up by other equipment that hopefully won't be a tuned circuit with an antenna, but shielded electronics with some thought to EMC prevention engineered into it.... esldude 1 Link to comment
sandyk Posted February 6, 2018 Share Posted February 6, 2018 This link was originally posted by Alfe in C.A. This should get up a few Objective noses. BYE ! http://www.johnvestman.com/digital_myth.htm How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file. PROFILE UPDATED 13-11-2020 Link to comment
Don Hills Posted February 6, 2018 Share Posted February 6, 2018 11 minutes ago, sandyk said: .. This should get up a few Objective noses. Only if you inhale. opus101 1 "People hear what they see." - Doris Day The forum would be a much better place if everyone were less convinced of how right they were. Link to comment
sandyk Posted February 6, 2018 Share Posted February 6, 2018 13 minutes ago, Don Hills said: Only if you inhale. Just thank your E.E. God that he isn't also a C.A. member ! Recording and Mastering Engineers are often able to hear things that brainwashed EE.s and Software designers keep insisting isn't possible . Reading big textbooks and dusty old white papers is a poor substitute for actually listening. G'night from Sydney Au. How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file. PROFILE UPDATED 13-11-2020 Link to comment
Popular Post mansr Posted February 6, 2018 Popular Post Share Posted February 6, 2018 1 hour ago, Spacehound said: "Any degradation of the digital waveform will have consequences, and when that waveform is degraded, there is no way to restore it properly. Once the fine detail is lost, it is lost forever. - C.H." That's bollox. When people like Charles Hansen and John Swenson, who really should know better, say such things, I have to suspect they do it because they know it sells. And then they get worshipped like some kind of messiah. Disgusting. esldude, Bystander, gridlock74 and 1 other 2 1 1 Link to comment
marce Posted February 6, 2018 Share Posted February 6, 2018 1 hour ago, sandyk said: Just thank your E.E. God that he isn't also a C.A. member ! Recording and Mastering Engineers are often able to hear things that brainwashed EE.s and Software designers keep insisting isn't possible . Reading big textbooks and dusty old white papers is a poor substitute for actually listening. G'night from Sydney Au. hearing things can be cured now with help, my voices I use to hear have diminished with the help of professionals, making the world a safer place.... Don Hills 1 Link to comment
marce Posted February 6, 2018 Share Posted February 6, 2018 29 minutes ago, mansr said: When people like Charles Hansen and John Swenson, who really should know better, say such things, I have to suspect they do it because they know it sells. And then they get worshipped like some kind of messiah. Disgusting. I find it strange that Audio is the only area of electronics where designers are worshipped, the only parallels I can draw is the fashion industry... Link to comment
adamdea Posted February 6, 2018 Share Posted February 6, 2018 5 hours ago, mansr said: When people like Charles Hansen and John Swenson, who really should know better, say such things, I have to suspect they do it because they know it sells. And then they get worshipped like some kind of messiah. Disgusting. "Any degradation of the digital waveform will have consequences, and when that waveform is degraded, there is no way to restore it properly. Once the fine detail is lost, it is lost forever. - C.H." This is why books nowadays are so much worse than they used to be. Every time the text is copied the typeface is degraded irretrievably. Fortunately Emily Dickinson is still just about ok, but Homer is hopeless: unless someone can find an original never before copied text the Iliad will be finished forever. You are not a sound quality measurement device Link to comment
esldude Posted February 6, 2018 Share Posted February 6, 2018 7 hours ago, marce said: As said it is a relevant paper but something simpler on BER or similar would be more illustrative of the point, someone did put up some figures and to be honest its a non issue these days in most instances... They would moan if we still controlled stuff using 4-20ma loops etc. LOL but then maybe it was better because is was analogue.... 4-20ma was a smoother more human control. One where noise manifested itself as merely noise. And always keep in mind: Cognitive biases, like seeing optical illusions are a sign of a normally functioning brain. We all have them, it’s nothing to be ashamed about, but it is something that affects our objective evaluation of reality. Link to comment
Speedskater Posted February 6, 2018 Share Posted February 6, 2018 1 hour ago, adamdea said: "Any degradation of the digital waveform will have consequences, and when that waveform is degraded, there is no way to restore it properly. Once the fine detail is lost, it is lost forever. - C.H." Mr. Hansen was wrong. It's not the fine details that are lost. The result is total decoding errors or drop-outs. Link to comment
adamdea Posted February 6, 2018 Share Posted February 6, 2018 18 minutes ago, Speedskater said: Mr. Hansen was wrong. It's not the fine details that are lost. The result is total decoding errors or drop-outs. I agree, but of course it is not "any degradation of the digital waveform" which does that; for a decent dac it's only really really gross degradations. The manual for the old Benchmark Dac1 showed how badly you can mangle the signal without any change in the output. This includes using 1000 feet of cable, dropping the signal amplitude by many db, or adding up to 2000 nanoseconds jitter. You are not a sound quality measurement device Link to comment
Spacehound Posted February 6, 2018 Share Posted February 6, 2018 16 minutes ago, Speedskater said: Mr. Hansen was wrong. It's not the fine details that are lost. The result is total decoding errors or drop-outs. He's not the only one. There's lots of garbage comes from 'respected' DAC and associated stuff manufacturers. Most of 'em just buy Sabre DAC chips for a few dollars each, implement what's on the free Sabre data sheet, add 200-20,000 dollars, there ya go, you is a 'respected' expert and the more you charge the more 'respected' you are. Link to comment
mansr Posted February 6, 2018 Share Posted February 6, 2018 5 minutes ago, Spacehound said: He's not the only one. There's lots of garbage comes from 'respected' DAC and associated stuff manufacturers. Most of 'em just buy Sabre DAC chips for a few dollars each, implement what's on the free Sabre data sheet, add 200-20,000 dollars, there ya go, you is a 'respected' expert and the more you charge the more 'respected' you are. Respect is earned. The bigger the earnings, the greater the respect. Link to comment
Ralf11 Posted February 6, 2018 Share Posted February 6, 2018 I guess people who don't understand digital transmission, need to believe in Magik so they can insist on the same files sounding different Link to comment
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