h a l f b a k e r y
If you need to ask, you can't afford it.
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You may or may not be aware that Sony have been busily shipping XCP software with their music discs, that basically is rootkit and shags your computer.
I've also always thought that vinyl sounds more "real" than CD. It could be redesigned to be smaller in size, and with modern technology be read
by a much finer needle than was originally available. However part of the fun of buying an old vinyl disc was the artwork that came with it.
Now there are many forms of rapid manufacturing processes involving the production of plastic prototypes and models. These are intended to avoid the need to go through the time consuming, expensive, and inflexible pattern making and casting process. It at heart involves the interpretation of digital instructions in the manufacture of a 3D model in either plastic or wax.
It struck me that those instructions can be sent over any distance you want. So if you had a minature Rapid Manufacturing Vat it would be possible to connect by phone line to a central database and download the pattern to any disc that you wanted.
So what's the point?
A) The whole process is unconnected to your computer so no risk of viruses, rootkit etc
B) You can listen to the full glory of vinyl
C) You can make as many copies as you want
D) Sony can boil their heads.
Sony should burn in hell
http://news.bbc.co....hnology/4406178.stm
[Jacob Marley, Nov 07 2005]
Sony backs down
http://news.yahoo.c...ony_copy_protection
[Shz, Nov 11 2005]
Short name, e.g., Bob's Coffee
Destination URL.
E.g., http://www.coffee.com/
Description (displayed with the short name and URL.)
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I would love to have a lathe in the corner of my sitting room so that I could cut acetates as and when I needed them. Printing the covers is more of a problem - or rather, downloading the artwork. All in all though, a fine plan. Especially part D). |
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The problem is the quality - whilst a vinyl is higher quality on an expensive player it degenerates much more quickly. Also, phone lines have limited bandwidth, especially when transmitting analogue (think how tinny the music is when you get put on hold). People say cds havent got the same quality as vinyl but infact it is more the atmosphere - listening to voodoo chile without the crackles of vinyl is not the same. |
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Cds sample the music 131072 times every second which means it can accurately reproduce any frequency up to about 40kHz which is more than enough. |
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On the list at the moment this sits above "Personnel Suppression Weapon". Personally, prefer "Downloadable Vinyl Personnel" and "Suppression Weapon". |
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Phone bandwidth isn't an issue, since you're dowloading a CAD model which will be a certain size and quality, and will take however long it takes. As [wags] pointed out, a lathe would be the best option. |
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Another thing has occured to me. The vast majority of the object being 3D printed, is a standard flat wide cylinder so this part of the instruction isn't needed. It's only the last few layers of the surface that are required. This should cut down on download times. And if you use a blank to build the surface onto, then the manufacture time is also cut down. Or as [Wags] says you use a removal process rather than an addition process by using a lathe then the technology would probably be cheaper. In fact if you used a laser etcher then it would be pretty quick as well. |
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//Cds sample the music 131072 times every second which means it can accurately reproduce any frequency up to about 40kHz which is more than enough.//
I think you'll find that CDs sample at 44.1 kHz, not 128. (MiniDisc is slightly better at 48 kHz.) Although that rate still covers all frequencies directly within normal human hearing, it misses out on the sum and difference tones which are an important part of music; when an instrument produces two tones of, say, 7040 Hz and 7060 Hz, a difference tone of 20 Hz and a sum tone of 14100 Hz are also discernible, and these, in turn, interact further. Vinyl (and other analog media) preserve these derived tones, but CD (and other sampled media) simply kill them. |
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//I've also always thought that vinyl sounds more "real" than CD.// And ironically, you're creating an analogue disk with digital information. |
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And bear in mind that sampling at 44.1kHz only allows you to approximate a tone of 22.05kHz at the highest, just outside our range of hearing. It's not more than enough, it's *just* enough because that was what it was designed to be. |
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Nice explanation of harmonics [angel] but I don't understand why a cd would have trouble with either 20Hz or 14.1Khz? In theory (and usually in practice) a cd can capture anything we can hear. Still miss vinyl though. |
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20 Hz and 14.1 kHz aren't a problem; I simply used those figures to illustrate sum and difference tones for anyone unfamiliar with the terms. A 28 kHz tone in the left channel of an analog recording could interact with a 30 kHz tone in the right channel to produce an audible 2 kHz difference tone (and a 58 kHz sum tone which could interact further). These tones would not appear in playback of a sampled recording because their constituent tones would have been removed (or rather, ignored) by the sampling. |
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<annoying whine>But WHY?</aw> Surely a microphone works on the same basic principle as the ear, so any vibration that's actually there is picked up (and by inference, any tone we think we hear but which isn't actually vibrating air molecules is just a product of our imagination)? I know this isn't really the right place for such questions, but hey. |
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It's called frequency response moom. Anything that passes audio through will emphasise certain frequencies and supress others. It will also have an upper and lower bound to the frequencies it can cope with. The human ear copes with roughly anything from 20Hz to 20kHz and so most audio equipment is designed to cope with all these frequencies, preferable without emphasising or suppressing any of them at all (known as a 'flat' frequency response). Some microphones can hear frequencies both lower and higher than we can, and some equipment can record and analyse these sounds, but most can't. Just like some cameras can photograph infra-red and uv, but most can't, simply because we don't need them to. |
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Aaaargh! Band-pass, Butterworth, aliasing and Nyquist... all running around in my head mocking me and my shoddy memory for my electronic circuits classes at uni... |
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[moom], you can't directly hear the 28 or the 30 kHz tones in my last example but you could hear the result of them being in the same place at the same time. You're not imagining this result; it's actually there, vibrating real air molecules. Digital audio removes the original high (inaudible) frequencies from the source recording so they don't even appear, so cannot produce the sum and difference tones in the final playback.
(Tries to think of an analogy.) Hold your hands a few inches apart, as though you're about to clap. Now (you probably won't actually be able to do this, but imagine it) move your right hand to clap every two seconds, and move your left hand every three seconds. You'll get a clap every six seconds; that's a difference tone. |
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Oh, okay. I get it now. Thanks. |
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[angel] - You should teach at sound college, you explain this stuff very well. |
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So, what I wantto know: If enough information was collected per a period of time could a digital recording be comparable to analogue? How much digital information would that be? I have heard rumors about the introduction into the market of HD CDs. Basically it would be one album on a DVD instead of a CD. Anyone? [angel]? |
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The problem is that you get into a very subjective area here - cd's actually provide a more accurate reproduction of the original sound than vinyl (angel will probably dispute this), it's just that vinyl can often sound "nicer". In fact there are many forms of distortion (magnetic tape, valve etc) which objectively degrade the sound while subjectively improving it. |
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There have been 24-bit 96kHz sampling systems around for a while now which is the sort of thing that hdcd's would use. This would give a more accurate reproduction than standard cds (noticable mainly in the highest frequencies and in quiet passages) but would not make it sound like vinyl. It is rather strange that 96kHz systems can reproduce frequencies up to 48kHz, whereas anything above 20kHz is a) inaudible, and b) invariably removed in the recording process. |
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[angel] - Just looked up some figures on vinyl. The best cutting lathes have a frequency response of 10Hz to 25kHz, which I suppose technically gives vinyl a marginal edge over cd (disregarding rather poor THD, inherent phase problems, lack of error correction etc...). You'd need some fairly kick-ass reproduction at home though :-) |
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There's a rule - I forget whose - that the sampling rate should be at least two, and preferably three, times the highest frequency to be sampled. Sampled audio should sound as good - that is, as faithful - as analog if the sampling rate is high enough. In practise, the sampling signal gets mixed up in the audio. You can use a filter to get rid of it, but then you also remove any intended signals in the same frequency band. The result may also sound just less pleasant, in a subjective way, which is why many people use valve (tube) amplifiers in hi-fi equipment; they add their own colour into the sound. (Personally I see no point in insisting on faithful recordings then imposing valve artifacts; better to add solid-state artifacts which are easier to control and remove. I reserve my valve amps for my guitars.)
[wags]: I coould never be a teacher; I'm too impatient. |
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Why not just digitally add scratches, pops, etc during playback? In theory, this would work like the 'add noise' filters they use to make digital film shots look like film film. |
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The scratches & pops are a direct result of Album Abuse! |
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The majority of my vinyl collection has no schrrittch-hmmmm or WHHHPOOHPs! It's only the ones I bought unseen for $0.25 a piece that have that. (It Irked me to no end that of the 40 titles I bought that way (& by no means is that the sum of my collection), that the Pink FLoyd albums were the ones that did that.) |
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I looked up the link & am wondering. How long ago was it that they put that crap on the CD's? Most of my CD collection is at least 5 years old as I stopped buying music after the change in my life represented by my 2 sons. I've put well over 150 CD's onto my computer at work & wonder about this BS Sony has pulled. |
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