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Sampling/Time Resolution - In search of sources
FreaqyFrequency
post Oct 4 2011, 21:36
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Posts: 58
Joined: 4-October 11
From: VA Beach, VA
Member No.: 94145



Greetings all,

I've been lurking on these forums for about the last year, and I finally signed up today to pick the brains of some of the more knowledgeable individuals here.

On Saturday, I'm giving an 8 minute informative speech on the essential elements of digital audio (PCM to be exact, leaving DSD out given the time limit), why it was a logical progression from analog recording and storage technology, and a brief sketch of lossy/lossless implementations of it.

My primary objective at this point is to get a rock solid source, stating that (and why) any sampling rate is able to capture a given bandlimited source with perfect time resolution (ignoring frequency response and filtering in this case, dealing only with time). I was encouraged to touch upon this point in particular because of a presentation I found on YouTube a few months back, whose essential message was "Digital is bad because you hear the music as packets rather than as an analog waveform" and was advocating that everyone dispense with their digital media and go get a turntable and vinyls. My intent is to disprove the "packets" notion, and this source is the closest I have seen to doing that as of now:

http://www.tonmeister.ca/main/textbook/node639.html

If anyone could supply further documentation (or their own findings/conclusions on the matter), that would be most appreciated. Thanks! smile.gif
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FreaqyFrequency
post Oct 8 2011, 17:33
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Group: Members
Posts: 58
Joined: 4-October 11
From: VA Beach, VA
Member No.: 94145



Thank you very much JJ, I've been following your work in particular for some time, between the thread at Skeptic back in 2005 and the Audio Myths Workshop at AES 2009. Your level of expertise is invaluable, and I thoroughly appreciate your chiming in here. smile.gif In fact, I read the link which krabapple posted as I was making final preparations to my Powerpoint yesterday, and considered adding in the "accurate to 346 picoseconds" blurb, but as you're about to see below, it's rather lucky that I didn't attempt to do so.

I gave the speech today, and the result...well, I had to trim the fat significantly and STILL ended up four minutes over the time budget, which means that I only got to mention CD and PCM in passing, while I did still cover the fact that, in CD form, PCM represents frequencies beyond the range of human hearing, and that its dynamic range can be as high as 130 dB (I had to bend this one for the sake of leaving out technicalities; this is of course when dither and noise shaping are used properly, and only in certain bands). My approach ended up being one focusing on the evolution of this technology (recording, manipulation, storage and playback that is) from the phonograph to PCM today. My teacher and even a couple classmates commented that they were very impressed by my level of confidence in discussing the material, so that (kinda sorta?) made up for going over time.

No recording, sadly, but I will tell you that a good amount of the speech was based directly on the first 8 minutes or so of this video here.

http://xiph.org/video/vid1.shtml

Monty is a far more eloquent/prepared speaker than I am, so if you haven't already seen this video, it's definitely worth it. No new information, only the fact that he summarizes so much, so neatly.

Thank you all again for your participation in this thread, I look forward to my stay here. I'm prepared to learn a whole lot more, since I know the end of the rabbit hole is a long way down from here. biggrin.gif

*Edit: I had missed the 2pi function in 1/(2pi*quant. levels*fs), so I guess that figure would actually be closer to 55 picoseconds. Either way, pretty far below the ability of any human being to distinguish a timing difference.

This post has been edited by FreaqyFrequency: Oct 8 2011, 17:58
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Posts in this topic
- FreaqyFrequency   Sampling/Time Resolution - In search of sources   Oct 4 2011, 21:36
- - saratoga   QUOTE (FreaqyFrequency @ Oct 4 2011, 16:3...   Oct 4 2011, 21:40
- - benski   http://www.dspguide.com/ch3/3.htm Another good to...   Oct 4 2011, 21:41
- - FreaqyFrequency   Wow, you guys are quick on the draw! Thorough...   Oct 4 2011, 21:56
- - C.R.Helmrich   Was about to post the link that benski already pos...   Oct 4 2011, 22:19
- - xnor   Some introductory wiki pages: Sampling Nyquist-Sha...   Oct 4 2011, 22:42
- - Speedskater   You might look through member "woodinville...   Oct 4 2011, 23:21
- - knutinh   It is called Shannon-Nyquist sampling theoreme, an...   Oct 5 2011, 01:44
- - Axon   All I can suggest is to read this section from the...   Oct 5 2011, 02:23
- - FreaqyFrequency   Again, many thanks for all the replies, extremely ...   Oct 5 2011, 03:14
|- - dhromed   QUOTE (FreaqyFrequency @ Oct 5 2011, 04:1...   Oct 5 2011, 09:25
|- - db1989   I, too, like that analogy—and dhromed’s! Thi...   Oct 5 2011, 19:54
- - drewfx   The critical piece of information to stress to ...   Oct 5 2011, 17:38
|- - benski   QUOTE (drewfx @ Oct 5 2011, 12:38) The cr...   Oct 5 2011, 18:02
|- - dhromed   QUOTE (drewfx @ Oct 5 2011, 18:38) When t...   Oct 6 2011, 10:03
- - FreaqyFrequency   That is a great analogy, and analogies will be a s...   Oct 5 2011, 19:02
- - DVDdoug   QUOTE When the digital signal is converted back to...   Oct 6 2011, 00:03
- - krabapple   If you want to see the sorts of trainwrecks that h...   Oct 6 2011, 01:22
|- - 2Bdecided   QUOTE (krabapple @ Oct 6 2011, 01:22) If ...   Oct 6 2011, 12:42
- - Woodinville   The time resolution of a PROPERLY reconstructed PC...   Oct 8 2011, 03:12
|- - Woodinville   QUOTE (Woodinville @ Oct 7 2011, 19:12) T...   Oct 9 2011, 00:04
|- - Northpack   QUOTE (Woodinville @ Oct 8 2011, 03:12) T...   Oct 9 2011, 11:28
|- - Woodinville   QUOTE (Northpack @ Oct 9 2011, 03:28) Tha...   Oct 9 2011, 11:45
- - FreaqyFrequency   Thank you very much JJ, I've been following yo...   Oct 8 2011, 17:33
- - FreaqyFrequency   So I was flipping through some of my documents as ...   Feb 12 2012, 23:47
- - MichaelW   As the thread has been resurrected, and as the mis...   Feb 13 2012, 01:48
- - 2Bdecided   QUOTE (MichaelW @ Feb 13 2012, 00:48) two...   Feb 13 2012, 16:12
- - knutinh   QUOTE (2Bdecided @ Feb 13 2012, 17:12) On...   Feb 13 2012, 22:21
- - MichaelW   QUOTE (2Bdecided @ Feb 14 2012, 04:12) Pr...   Feb 13 2012, 23:02


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