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Does downgrading from 24/192 to 16/44.1 hurt?, Vynil rips
krafty
post Apr 2 2013, 19:22
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I was wondering if downgrading, with sox, material with 24-bit and 192kHz samplerate, to 16-bit and 44.1kHz samplerate hurts a lot.
Not that I have noticed anything, but is this a dirty technical procedure?
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Nick.C
post Apr 2 2013, 19:31
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Why would it?

From what I have read, 16/44.1 has not yet been proven to be inadequate as a final delivery format, full stop.

Wasting storage space storing the signal between 22.05kHz and 96kHz seems wasteful as it is inaudible to a (human) listener.

16-bits is also considered to be more than enough to store the full range of vinyl.


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greynol
post Apr 2 2013, 19:37
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While this might be a blatant appeal to authority, isn't it also widely held here that sox as one of the best sample rate converters in terms of performance data?


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krafty
post Apr 2 2013, 19:40
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Yes Nick.C,

This is my understanding too.

However I have some vinyls that I happen to found very good rips but they are 24/192, that is, too overkill.
Since the person ripped on such high-resolutions, does down-sample cause it to have artifacts like "horribly distorted" sound as I recollect someone said here that "downsample" was worse than "upsample".
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Apesbrain
post Apr 2 2013, 19:59
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QUOTE (krafty @ Apr 2 2013, 14:40) *
However I have some vinyls that I happen to found very good rips but they are 24/192, that is, too overkill.
Since the person ripped...

Caution, you may be on thin ice with regard to TOS#9.
Edited: Allowing for the possibility that you actually also own the physical vinyl; at least that's a defensible, "gray" area.

This post has been edited by Apesbrain: Apr 2 2013, 20:04
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greynol
post Apr 2 2013, 20:02
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QUOTE (krafty @ Apr 2 2013, 11:40) *
does down-sample cause it to have artifacts like "horribly distorted" sound as I recollect someone said here that "downsample" was worse than "upsample".

If your recollection did not include seeing ABX results then you're best served by purging it from your memory.

Now if you're truly concerned, I think you would perform your own ABX testing to satisfy this concern, rather than simply rely on what someone says once again. This is not to say that I don't trust Nick.C.


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greynol
post Apr 2 2013, 20:05
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QUOTE (Apesbrain @ Apr 2 2013, 11:59) *
Caution, you may be on thin ice with regard to TOS#9.
Edited: Allowing for the possibility that you may actually also own the physical vinyl; at least that's a defensible, "gray" area.

So long as he doesn't go into any more detail by specifying where or how, I think the topic at hand is worth keeping alive. In the future, krafty, try to avoid saying things that might draw this kind of attention.

This post has been edited by greynol: Apr 2 2013, 20:06


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krafty
post Apr 2 2013, 20:06
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QUOTE
Caution, you may be on thin ice with regard to TOS#9.
Edited: Allowing for the possibility that you may actually also own the physical vinyl; at least that's a defensible, "gray" area.


Ok. No further posts on this.

QUOTE
If your recollection did not include seeing ABX results then you're best served by purging it from your memory.


I remember he was a high-regarded member here, he elaborated some of the listening tests. I'll look for that post to check it out.
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pdq
post Apr 2 2013, 20:18
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QUOTE (krafty @ Apr 2 2013, 15:06) *
I remember he was a high-regarded member here, he elaborated some of the listening tests. I'll look for that post to check it out.

This would have gone much more smoothly if you had initially linked to this person's post and then asked if his concerns were valid/applied to your situation.
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mjb2006
post Apr 2 2013, 20:39
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Of course we don't listen with our eyes, but the differences between sample rate converters are demonstrated visually at http://src.infinitewave.ca/ ... There you will find that SoX is among the best, at least when converting from 96 kHz to 44.1, which is all they tested. (Generally I would say that any bright non-purple lines on the lower two-thirds of the graph, or to the right of the main peak, indicate a risk of audible problems in actual music.)

When ripping with peaks near 0 dBFS, vinyl's noise floor (the sound of vinyl rushing past the stylus in an empty groove) is around -50 to -60 dBFS, which is in the 10-bit range, so I highly doubt reducing from 24 to 16 bits ever could make a difference, even during the silent parts. Can you hear someone whispering when you're running a vacuum cleaner? Would you consider the whispering to be unwanted noise that reduces the "quality" of other sounds in the room?

This post has been edited by mjb2006: Apr 2 2013, 20:41
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DVDdoug
post Apr 3 2013, 01:56
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QUOTE
does down-sample cause it to have artifacts like "horribly distorted" sound as I recollect someone said here that "downsample" was worse than "upsample".
No!!!! I've never heard ANY difference when downsampling to 44.1kHz.

Downsampling throws-away information, and upsampling does not. If you downsample to 8kHz at 8-bits, you WILL notice the quality loss. wink.gif But, 44.1kHz/16-bits is better than human hearing and far-better than analog vinyl. Any information that's thrown-away is mostly noise, perhaps including some supersonic noise. In any case, nothing audible is lost.

Upsampling only the bit-depth is mathematically exact. So, you can go from 16-bits to 24-bits, and it's totally reversible... If you downsample back to 16-bits, you'll get the exact-same bytes. It's sort-of like writing 1000.000 instead of 1000. It takes more space to add zeros after the decimal point, but it doesn't add information. In fact, if you upsample the bit depth you are simply adding zero-bits to a binary number.

That's not generally true if you upsample the sample rate, even if you simply double the sample rate. If you upsample from 44.1kHz to 88.2kHz, and then back down to 44.1, there is interpolation and filtering. And with filtering there is always rounding. These teeny-tiny rounding errors are NOT audible, but the process is not mathematically perfect and the bytes will be different.

Of course, you don't automatically "improve quality" or "add information" when you upsample. The only time I upsample is when I'm going from CD (44.1kHz) to DVD (48kHz). It would also make sense to upsample if you are working on an audio project (mixing, etc.) and most of the project is at one sample rate, but you have one additional file at a lower sample rate. In that case, your DAW (digital audio workstation) will usually automatically re-sample everything to your "project settings".

This post has been edited by DVDdoug: Apr 3 2013, 01:57
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greynol
post Apr 3 2013, 02:16
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QUOTE (DVDdoug @ Apr 2 2013, 17:56) *
If you downsample back to 16-bits, you'll get the exact-same bytes.

Best practice is to use dither when reducing bit-depth in which case the process is not reversible.


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bandpass
post Apr 3 2013, 08:12
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QUOTE (DVDdoug @ Apr 3 2013, 00:56) *
If you upsample from 44.1kHz to 88.2kHz, and then back down to 44.1, there is interpolation and filtering. And with filtering there is always rounding. These teeny-tiny rounding errors are NOT audible, but the process is not mathematically perfect and the bytes will be different.

It doesn't have to be mathematically perfect: as long as the rounding error is (a few times) smaller than the quantisation error, then the bytes will be the same (assuming of course, a band-limited signal). And this is the case for any ratio, not just x2.
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cliveb
post Apr 3 2013, 09:48
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QUOTE (krafty @ Apr 2 2013, 19:40) *
However I have some vinyls that I happen to found very good rips but they are 24/192, that is, too overkill.
Since the person ripped on such high-resolutions, does down-sample cause it to have artifacts like "horribly distorted" sound as I recollect someone said here that "downsample" was worse than "upsample".

OK, you've got a vinyl rip at 24/192.

The worst conceivable way of converting it to 16/48 would be to throw away 3 out of every 4 samples without bothering to apply an anti-aliaing filter (ie. just keep every fourth sample), and to truncate every sample to 16 bits without dithering.

Since the source material was vinyl, I suspect you may very well not hear any difference even after such a ham-fisted approach. A well-executed downsampling using a decent application like sox will be completely benign.
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