rocky500 Posted June 26, 2013 Posted June 26, 2013 (edited) I was reading up on the Oppo Bluray player and came across this Interesting http://lavryengineering.com/pdfs/lavry-sampling-theory.pdf Moved my other part to Room accoustics Edited June 26, 2013 by rocky500
davewantsmoore Posted June 26, 2013 Posted June 26, 2013 http://lavryengineering.com/pdfs/lavry-sampling-theory.pdf If I were preparing my "bible", this paper would be in it. It needs to be noted carefully though that this paper is about sampling (putting things into the digital system) ... not taking them out again (eg. playback).... playing back audio at higher rates (oversampling, etc), can offer benefits.
firedog Posted June 26, 2013 Posted June 26, 2013 (edited) I was reading up on the Oppo Bluray player and came across this Interesting http://lavryengineering.com/pdfs/lavry-sampling-theory.pdf Moved my other part to Room accoustics If I were preparing my "bible", this paper would be in it. It needs to be noted carefully though that this paper is about sampling (putting things into the digital system) ... not taking them out again (eg. playback).... playing back audio at higher rates (oversampling, etc), can offer benefits. Read the article and then search for other competent engineers who totally disagree with approach and conclusion, and will give you all sorts of learned reasoning about why 4X sampling rates and above DO work and DO make sense. I don't think there is anything like a "Bible" in audio. In the end, forget all the theories - listen and buy what sounds good to you. Concentrating too much on the technical side and making decisions that way will only take away from your enjoyment of the music in the end (note, I did say "too much"). It's how it's sounds in the end that counts, not the theory behind it. Edited June 26, 2013 by firedog 1
Newman Posted June 26, 2013 Posted June 26, 2013 In the end, forget all the theories - listen and buy what sounds good to you. Spoken like a true consumer. The economy thanks you. OTOH there is a theory of how to listen ...better remember not to forget that one. 2
firedog Posted June 29, 2013 Posted June 29, 2013 Spoken like a true consumer. The economy thanks you. OTOH there is a theory of how to listen ...better remember not to forget that one. Newman- I am all in favor of learning to improve listening skills. That is very different from judging equipment or recordings based on a technical paper or someone's idea about the "right" way to make equipment or record music. Whatever you think of Lavry and the approach in the paper in the link, the fact remains that the position in the paper is not "agreed wisdom" among equipment designers, audiophiles, or qualified engineers. The Web is full of learned technical discussions disagreeing about just such points. That was the point of my post advising the poster to listen and decide, rather than basing his choices on a position staked out in a paper. Again, improving listening skills is possible and recommended, so no argument with you there.
Guest fordgtlover Posted June 29, 2013 Posted June 29, 2013 Newman- I am all in favor of learning to improve listening skills. That is very different from judging equipment or recordings based on a technical paper or someone's idea about the "right" way to make equipment or record music. Whatever you think of Lavry and the approach in the paper in the link, the fact remains that the position in the paper is not "agreed wisdom" among equipment designers, audiophiles, or qualified engineers. The Web is full of learned technical discussions disagreeing about just such points. That was the point of my post advising the poster to listen and decide, rather than basing his choices on a position staked out in a paper. Again, improving listening skills is possible and recommended, so no argument with you there. You might be surprised by what we do actually know. here are some really useful videos on the topic created by people who do this stuff for a living http://www.xiph.org/video/
firedog Posted July 3, 2013 Posted July 3, 2013 (edited) You might be surprised by what we do actually know. here are some really useful videos on the topic created by people who do this stuff for a living http://www.xiph.org/video/ And again, the web is full of people debunking the xiph video. Not saying it is incorrect, just repeating that knowledgeable people disagree on this topic, so it's one of the last ones that I think you can safely claim we KNOW the answer to. BTW, not irrelevant to note that the xiph people have a commercial interest in hi-res not being a necessary format, i.e., one that audibly improves sound reproduction. Edited July 3, 2013 by firedog
Guest fordgtlover Posted July 3, 2013 Posted July 3, 2013 And again, the web is full of people debunking the xiph video. Not saying it is incorrect, just repeating that knowledgeable people disagree on this topic, so it's one of the last ones that I think you can safely claim we KNOW the answer to. BTW, not irrelevant to note that the xiph people have a commercial interest in hi-res not being a necessary format, i.e., one that audibly improves sound reproduction. What is the story with xiph having an interest in hi-res and its purported sound improvement not being necessary? They are focused on open source multimedia standards for web - they aren't commercial. What part of the picture am I not seeing?
firedog Posted July 5, 2013 Posted July 5, 2013 (edited) What is the story with xiph having an interest in hi-res and its purported sound improvement not being necessary? They are focused on open source multimedia standards for web - they aren't commercial. What part of the picture am I not seeing? First, they have an interest in promoting ogg vorbis, a lossy format. So it is in their interest to denigrate full resolution as "unnecessary"; otherwise users might not want their format. Second, they can license software or packages they've developed using the open source code to commercial interests. So again, it is in their interest to see their standard adopted, and not see users go over to lossless or hi-res. And if you don't think that has any influence, at least as developers and promoters of ogg vorbis, they can't exactly be seen as an objective voice in the debate. Edited July 5, 2013 by firedog 1
Guest fordgtlover Posted July 5, 2013 Posted July 5, 2013 First, they have an interest in promoting ogg vorbis, a lossy format. So it is in their interest to denigrate full resolution as "unnecessary"; otherwise users might not want their format. Second, they can license software or packages they've developed using the open source code to commercial interests. So again, it is in their interest to see their standard adopted, and not see users go over to lossless or hi-res. And if you don't think that has any influence, at least as developers and promoters of ogg vorbis, they can't exactly be seen as an objective voice in the debate. Like any standards organisation of course it is their role to promote their own standards, but they promote a range of other open standards as well including FLAC, which is lossless, supports hi-res and is free. https://wiki.xiph.org/index.php/Main_Page Ogg-Vorbis is released under the GNU GPL - it's also free. https://en.wikipedia.org/wiki/GNU_General_Public_License Vorbis was developed because of the threat back in the day to start charging for the use of MP3. Xiph is a non-profit organisation developing open web multimedia standards. Can you explain again why Xiph aren't the good guys? And, what do you mean by full resolution? 2
firedog Posted July 7, 2013 Posted July 7, 2013 (edited) Like any standards organisation of course it is their role to promote their own standards, but they promote a range of other open standards as well including FLAC, which is lossless, supports hi-res and is free. https://wiki.xiph.org/index.php/Main_Page Ogg-Vorbis is released under the GNU GPL - it's also free. https://en.wikipedia.org/wiki/GNU_General_Public_License Vorbis was developed because of the threat back in the day to start charging for the use of MP3. Xiph is a non-profit organisation developing open web multimedia standards. Can you explain again why Xiph aren't the good guys? And, what do you mean by full resolution? It has nothing to do with being good guys. Simply put, they have a point of view or to put it another way "an axe to grind". BTW, the head of "non-profit" ziph.org has a JOB working on and promoting Ogg Vorbis at Red Hat, a commercial enterprise. Full resolution=not lossy. I'm not sure why it is hard to understand that someone who is actively promoting a lossy format has an interest in saying a non-lossy hi-res format is, at best, unnecessary. In any case, I think anyone who reads the material should be aware of it. Again, you posted a link and recommended this article and implied it is the "truth". Like most material saying hi-res is unnecessary, it purports to state as "fact" some things that are in dispute. And while the authors may "do this for a living" - so do other people who don't agree with them. You might be surprised that everything we think we do "know" - we don't know it to the level of certainty you imply. Edited July 7, 2013 by firedog
davewantsmoore Posted July 7, 2013 Posted July 7, 2013 Read the article and then search for other competent engineers who totally disagree with approach and conclusion, and will give you all sorts of learned reasoning Link to the ones you're talking about ?! There is nothing controversial in the Lavry paper IMHO.
davewantsmoore Posted July 7, 2013 Posted July 7, 2013 That is very different from judging equipment or recordings based on a technical paper Somewhat backwards IMHO. No one's going to judge something based on a technical paper..... but when they do decide if they like the sound or not.... they might discover "why" by understanding technical things. 1
davewantsmoore Posted July 7, 2013 Posted July 7, 2013 (edited) the fact remains that the position in the paper is not "agreed wisdom" among equipment designers, audiophiles, or qualified engineers. More info please (the devil is in the details). I don't agree that this is not accepted wisdom. There is nothing controversial in the Lavry paper. And again, the web is full of people debunking the xiph video Debunking is a very strong word. There are some reasons why high rates and depths are desirable... but there is nothing "untrue" in the Xiph papers or videos. xiph people have a commercial interest in hi-res not being a necessary format, i.e., one that audibly improves sound reproduction. Why? I don't agree. Edited July 7, 2013 by davewantsmoore
davewantsmoore Posted July 7, 2013 Posted July 7, 2013 (edited) First, they have an interest in promoting ogg vorbis, a lossy format. So it is in their interest to denigrate full resolution as "unnecessary"; So why do the Voris people recommend lossless formats for archival purposes. They are not stupid, and understand there are things a lossless codec is more suited to. Ogg. Their container format can hold other codecs of audio than Vorbis, like FLAC or PCM. If they thought such formats were undesirable, then why would they design their own container format to hold them?! Edited July 7, 2013 by davewantsmoore
davewantsmoore Posted July 7, 2013 Posted July 7, 2013 And if you don't think that has any influence, at least as developers and promoters of ogg vorbis, they can't exactly be seen as an objective voice in the debate. Absolute drivel. <facepalm> Whether their voice is valid is based on the justification for their position. Science is not a democracy. It is completely possible to separate the concern you raise above .... from the evaluation of whether what they're saying is correct. CarMakerX says the running costs of their new hybrid car are really low. Do we just say, "oh you can't be very objective" .... or do we test their claim independently of such considerations ?!
davewantsmoore Posted July 7, 2013 Posted July 7, 2013 Again, you posted a link and recommended this article and implied it is the "truth". Like most material saying hi-res is unnecessary, it purports to state as "fact" some things that are in dispute. And while the authors may "do this for a living" - so do other people who don't agree with them. There are a lot of people on the internet who don't really know what they're talking about... that's for sure. Like I said before. The Lavry and Xiph articles are factual. They make some subjective conclusions which could be debated, depending on what you are trying to achieve.... but the facts they cover in their discussion, are just that. Facts. If we can show some publications which present that the facts covered in those articles are not actually facts.... then you'll see it on the 6 oclock news.
firedog Posted July 7, 2013 Posted July 7, 2013 (edited) There are a lot of people on the internet who don't really know what they're talking about... that's for sure. Like I said before. The Lavry and Xiph articles are factual. They make some subjective conclusions which could be debated, depending on what you are trying to achieve.... but the facts they cover in their discussion, are just that. Facts. If we can show some publications which present that the facts covered in those articles are not actually facts.... then you'll see it on the 6 oclock news. Well, it certainly won't be on any 6 o'clock news. Maybe the Daily Audiophile. Factual...well yes the Nyquist theorem exists and is "correct". That actually doesn't mean much in terms of sound reproduction. The theory, for instance, assumes infinite filters exist and infinite bit depth is available. None of those exist in real life. So saying "the articles are factual...they make some conclusions which could be debated" is sort of meaningless when you headline a "factual" article "24/192 downloads are silly". Lavry is pretty much a minority of one (maybe two) in the audio world in his specific conclusions and his point of view. I'm not going to supply you with links,then we'll get in a debate about the quality of the links. Take 5 minutes and find those who disagree with him and ALSO are qualified to know what they are talking about. It's not that hard. Edited July 7, 2013 by firedog
davewantsmoore Posted July 7, 2013 Posted July 7, 2013 Well, it certainly won't be on any 6 o'clock news. No, it will. It would affect almost every branch of science to know soundwaves/vibration/pressure behaves differently.
davewantsmoore Posted July 7, 2013 Posted July 7, 2013 Factual...well yes the Nyquist theorem exists and is "correct". That actually doesn't mean much in terms of sound reproduction. The theory, for instance, assumes infinite filters exist and infinite bit depth is available. None of those exist in real life. So saying "the articles are factual...they make some conclusions which could be debated" is sort of meaningless when you headline a "factual" article "24/192 downloads are silly" The Lavry article is not about sound reproduction! I'm not going to supply you with links,then we'll get in a debate about the quality of the links. I wouldn't do that...... .... but if I DID, it would actually be about the quality of their reasoning, correctness and justification ..... so if I did that, and I was actually correct, then you'd have to concede that the link you'd provided was not evidence. Lavry is pretty much a minority of one (maybe two) in the audio world in his specific conclusions and his point of view. Wow. I don't think I could raise my eyebrows any higher. How about this then. Can you tell me which of his "specific conclusions" are disagreed with? .... and then I might be able to try and discover why/why/how they are disagreed with.
davewantsmoore Posted July 7, 2013 Posted July 7, 2013 The theory, for instance, assumes infinite filters exist and infinite bit depth is available. None of those exist in real life. Of course. There are practical consequences of not having infinite functions available... but these consequences are easy enough to quantify and discuss. So saying "the articles are factual...they make some conclusions which could be debated" is sort of meaningless when you headline a "factual" article "24/192 downloads are silly". The reasoning for the Xiph article "24/192 downloads are silly" are all sound reasons. There are of course situation where storing the highest quality is desirable .... and there are practical reasons why higher rates and depths might work better in a converter ... but these can be reconciled with over-sampling, and do not require actual higher rates and depths in the original source.... Ofcourse, if you wanted to avoid oversampling (which you might if you device works better without it)... then you'd need to again, begin with higher rates and depths... either with more data to begin with .... or again, oversampling.... but done outside the playback loop.
davewantsmoore Posted July 7, 2013 Posted July 7, 2013 Conclusion: There is an inescapable tradeoff between faster sampling on one hand and a loss of accuracy, increased data size and much additional processing requirement on the other hand. AD converter designers can not generate 20 bits at MHz speeds, yet they often utilize a circuit yielding a few bits at MHz speeds as a step towards making many bits at lower speeds. The compromise between speed and accuracy is a permanent engineering and scientific reality. Sampling audio signals at 192KHz is about 3 times faster than the optimal rate. It compromises the accuracy which ends up as audio distortions. While there is no up side to operation at excessive speeds, there are further disadvantages: 1. The increased speed causes larger amount of data (impacting data storage and data transmission speed requirements). 2. Operating at 192KHz causes a very significant increase in the required processing power, resulting in very costly gear and/or further compromise in audio quality. The optimal sample rate should be largely based on the required signal bandwidth. Audio industry salesman have been promoting faster than optimal rates. The promotion of such ideas is based on the fallacy that faster rates yield more accuracy and/or more detail. Weather motivated by profit or ignorance, the promoters, leading the industry in the wrong direction, are stating the opposite of what is true. Take your pick....
daemon d Posted July 7, 2013 Posted July 7, 2013 What does the weather have to do with it? Is it related to global warming. Not sure whether or not to believe that... Sorry just being an arse, no discussion need be entered into. 2
davewantsmoore Posted July 7, 2013 Posted July 7, 2013 What does the weather have to do with it? HAH!... Nice spot.
aechmea Posted July 7, 2013 Posted July 7, 2013 What does the weather have to do with it? Is it related to global warming. Not sure whether or not to believe that... Sorry just being an arse, no discussion need be entered into. I saw that too. Had a chuckle. Not quite as frustrating as seeing people interchange 'then' and 'than' - which aren't even homophones. Sorry.
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