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#1
Posted to rec.audio.pro
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The sample rate/bit depth war
I really don't want to start this battle again, but I'm trying to justify
to my video counterparts that 48K/16 sampling is adequate for a blu-ray disk that can handle 96K/24. Here's the test I'm planning: 1) Let them choose a blu-ray soundtrack that they think exemplifies the niceties of 96K sampling. 2) Rip that sample bit-accurate into 96/24. 3) Create an disk from the ripped copy still in 96/24. 4) Reduce the level by 48 dB then raise it back again, effective emptying the bottom 8 bits. 5) Create another disk as in (3) above at 96/24. 6) Have them pick between disks from (3) and (5) in a blind test. By using copies made from the same source using the same steps and playing back in the same machine with the same converters, I should get a fair test. There is a pass of decompression/recompression when reading/creating a blu-ray disk, but both disks will have the same processing. Anything wrong with this scenario? |
#2
Posted to rec.audio.pro
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The sample rate/bit depth war
Carey Carlan wrote:
I really don't want to start this battle again, but I'm trying to justify to my video counterparts that 48K/16 sampling is adequate for a blu-ray disk that can handle 96K/24. Here's the test I'm planning: 1) Let them choose a blu-ray soundtrack that they think exemplifies the niceties of 96K sampling. 2) Rip that sample bit-accurate into 96/24. 3) Create an disk from the ripped copy still in 96/24. 4) Reduce the level by 48 dB then raise it back again, effective emptying the bottom 8 bits. Maybe, maybe not - I'd look at the samples first. 5) Create another disk as in (3) above at 96/24. 6) Have them pick between disks from (3) and (5) in a blind test. By using copies made from the same source using the same steps and playing back in the same machine with the same converters, I should get a fair test. There is a pass of decompression/recompression when reading/creating a blu-ray disk, but both disks will have the same processing. Anything wrong with this scenario? Take both disks, rip 'em, calculate the difference signal* and see. *in CoolEdit, this involves copying one disk's worth, and using the "mix paste" tool with the 'invert' checkbox selected. -- Les Cargill |
#3
Posted to rec.audio.pro
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The sample rate/bit depth war
On Nov 14, 4:22*pm, Carey Carlan wrote:
I really don't want to start this battle again, but I'm trying to justify to my video counterparts that 48K/16 sampling is adequate for a blu-ray disk that can handle 96K/24. Here's the test I'm planning: 1) Let them choose a blu-ray soundtrack that they think exemplifies the niceties of 96K sampling. 2) Rip that sample bit-accurate into 96/24. 3) Create an disk from the ripped copy still in 96/24. 4) Reduce the level by 48 dB then raise it back again, effective emptying the bottom 8 bits. 5) Create another disk as in (3) above at 96/24. 6) Have them pick between disks from (3) and (5) in a blind test. By using copies made from the same source using the same steps and playing back in the same machine with the same converters, I should get a fair test. *There is a pass of decompression/recompression when reading/creating a blu-ray disk, but both disks will have the same processing. Anything wrong with this scenario? This only addresses the word length. Some disks may have 48k sample rate disguised as 96k. Examine the data to determine both the true sample rate and word length of the audio. Then you can do 3 tests, one for 96-48-96, one for 24-16-24, and the big one ... 96/24-48/16-96-24. Personally, I think 48/24 is more than adequate, and that outside of a "monitoring" environment very few listeners will discern anything better than 48/16. JMO. I would have liked CDs to adopt 48/16 at the beginning, but it's way too late to talk about that now. rd |
#4
Posted to rec.audio.pro
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The sample rate/bit depth war
On Nov 14, 9:26*pm, RD Jones wrote:
On Nov 14, 4:22*pm, Carey Carlan wrote: I really don't want to start this battle again, but I'm trying to justify to my video counterparts that 48K/16 sampling is adequate for a blu-ray disk that can handle 96K/24. Here's the test I'm planning: 1) Let them choose a blu-ray soundtrack that they think exemplifies the niceties of 96K sampling. 2) Rip that sample bit-accurate into 96/24. 3) Create an disk from the ripped copy still in 96/24. 4) Reduce the level by 48 dB then raise it back again, effective emptying the bottom 8 bits. 5) Create another disk as in (3) above at 96/24. 6) Have them pick between disks from (3) and (5) in a blind test. By using copies made from the same source using the same steps and playing back in the same machine with the same converters, I should get a fair test. *There is a pass of decompression/recompression when reading/creating a blu-ray disk, but both disks will have the same processing. Anything wrong with this scenario? This only addresses the word length. Some disks may have 48k sample rate disguised as 96k. Examine the data to determine both the true sample rate and word length of the audio. Then you can do 3 tests, one for 96-48-96, one for 24-16-24, and the big one ... 96/24-48/16-96-24. Personally, I think 48/24 is more than adequate, and that outside of a "monitoring" environment very few listeners will discern anything better than 48/16. JMO. I would have liked CDs to adopt 48/16 at the beginning, but it's way too late to talk about that now. rd- Hide quoted text - - Show quoted text - Take this drivel and shove it - I'm not readin this no more. |
#5
Posted to rec.audio.pro
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The sample rate/bit depth war
"Carey Carlan" wrote in message
I really don't want to start this battle again, but I'm trying to justify to my video counterparts that 48K/16 sampling is adequate for a blu-ray disk that can handle 96K/24. Here's the test I'm planning: 1) Let them choose a blu-ray soundtrack that they think exemplifies the niceties of 96K sampling. 2) Rip that sample bit-accurate into 96/24. By what means that avoids the copy protection? 3) Create an disk from the ripped copy still in 96/24. 4) Reduce the level by 48 dB then raise it back again, effective emptying the bottom 8 bits. Again, by what means? Emptying the bottom bits with common audio software is not always trivial because they do their work in 32 bit floating point. My preferred method for emptying the lower bits is actually pretty obvious - convert it to 16 bits and then convert it back to 24 bits. This is basically the methodology described in several recent AES papers including one by John Vanderkooy at the recent San Francisco meeting. 5) Create another disk as in (3) above at 96/24. 6) Have them pick between disks from (3) and (5) in a blind test. By using copies made from the same source using the same steps and playing back in the same machine with the same converters, I should get a fair test. There is a pass of decompression/recompression when reading/creating a blu-ray disk, but both disks will have the same processing. Anything wrong with this scenario? This has been done many times and the results are that nobody hears a difference unless they do something like listen to very faint passages with high gain settings that would results in excess blasting during the loud passages. |
#6
Posted to rec.audio.pro
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The sample rate/bit depth war
"Arny Krueger" wrote in
: "Carey Carlan" wrote in message I really don't want to start this battle again, but I'm trying to justify to my video counterparts that 48K/16 sampling is adequate for a blu-ray disk that can handle 96K/24. Here's the test I'm planning: 1) Let them choose a blu-ray soundtrack that they think exemplifies the niceties of 96K sampling. 2) Rip that sample bit-accurate into 96/24. By what means that avoids the copy protection? The program is called "AnyDVDHD". 3) Create an disk from the ripped copy still in 96/24. 4) Reduce the level by 48 dB then raise it back again, effective emptying the bottom 8 bits. Again, by what means? Emptying the bottom bits with common audio software is not always trivial because they do their work in 32 bit floating point. Hmm. Correct. In 32 bit, that would be a 96 dB cut and restore. My preferred method for emptying the lower bits is actually pretty obvious - convert it to 16 bits and then convert it back to 24 bits. I was trying to avoid any data conversions. By doing nothing but changing levels I might convince others that no magic was happening. This is basically the methodology described in several recent AES papers including one by John Vanderkooy at the recent San Francisco meeting. 5) Create another disk as in (3) above at 96/24. 6) Have them pick between disks from (3) and (5) in a blind test. By using copies made from the same source using the same steps and playing back in the same machine with the same converters, I should get a fair test. There is a pass of decompression/recompression when reading/creating a blu-ray disk, but both disks will have the same processing. Anything wrong with this scenario? This has been done many times and the results are that nobody hears a difference unless they do something like listen to very faint passages with high gain settings that would results in excess blasting during the loud passages. I completely agree with the conclusions. I'm trying to convince those I work with that my formats are adequate so I won't having to work in extreme HD which is slower with bigger files and no benefit. |
#7
Posted to rec.audio.pro
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The sample rate/bit depth war
Carey Carlan wrote:
I really don't want to start this battle again, but I'm trying to justify to my video counterparts that 48K/16 sampling is adequate for a blu-ray disk that can handle 96K/24. Here's the test I'm planning: 1) Let them choose a blu-ray soundtrack that they think exemplifies the niceties of 96K sampling. 2) Rip that sample bit-accurate into 96/24. 3) Create an disk from the ripped copy still in 96/24. 4) Reduce the level by 48 dB then raise it back again, effective emptying the bottom 8 bits. 5) Create another disk as in (3) above at 96/24. 6) Have them pick between disks from (3) and (5) in a blind test. By using copies made from the same source using the same steps and playing back in the same machine with the same converters, I should get a fair test. There is a pass of decompression/recompression when reading/creating a blu-ray disk, but both disks will have the same processing. Anything wrong with this scenario? Make a third disk that is a 48/16 disk but with the levels bumped up by 1 dB. Throw it into the mix. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#8
Posted to rec.audio.pro
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The sample rate/bit depth war
On Nov 15, 9:32 am, Carey Carlan wrote:
I was trying to avoid any data conversions. By doing nothing but changing levels I might convince others that no magic was happening. I do this all the time by loading a "high-res" file into Sound Forge, then reducing the bit depth and saving that as a copy. This is more direct than lowering and raising the gain, which may not do what you think it does. Other than that, I agree with your general concept of testing people blind. --Ethan |
#9
Posted to rec.audio.pro
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The sample rate/bit depth war
This has been done many times and the results are that nobody hears a difference unless they do something like listen to very faint passages with high gain settings that would results in excess blasting during the loud passages. I completely agree with the conclusions. *I'm trying to convince those I work with that my formats are adequate so I won't having to work in extreme HD which is slower with bigger files and no benefit.- you never will convince them these kind of audiophool things take the form of religious beliefs... no amount of sceintific evidence will change their belief.. Mark |
#10
Posted to rec.audio.pro
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The sample rate/bit depth war
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#11
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The sample rate/bit depth war
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#12
Posted to rec.audio.pro
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The sample rate/bit depth war
"Carey Carlan" wrote in message
(Scott Dorsey) wrote in : Make a third disk that is a 48/16 disk but with the levels bumped up by 1 dB. Throw it into the mix. --scott Oh, that's sneaky! I'll do just that. Not sneaky, but an excellent double check. Some listeners just don't get it, and failing to hear a 1 dB (or maybe 2 dB) overall level shift will expose them. If *everybody* fails to detect the 1 dB shift, there could be a problem with the program material that you are using. I've seen normally good listeners falter with program material that jumps around too much or is really unfamiliar. |
#13
Posted to rec.audio.pro
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The sample rate/bit depth war
"Arny Krueger" wrote in
: "Carey Carlan" wrote in message (Scott Dorsey) wrote in : Make a third disk that is a 48/16 disk but with the levels bumped up by 1 dB. Throw it into the mix. --scott Oh, that's sneaky! I'll do just that. Not sneaky, but an excellent double check. Some listeners just don't get it, and failing to hear a 1 dB (or maybe 2 dB) overall level shift will expose them. If *everybody* fails to detect the 1 dB shift, there could be a problem with the program material that you are using. I've seen normally good listeners falter with program material that jumps around too much or is really unfamiliar. Sneaky in the sense that I've never heard an audio test that didn't prefer the louder signal (within reason). I'm dealing with video people. I don't believe they'd realize that louder has an advantage. |
#14
Posted to rec.audio.pro
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The sample rate/bit depth war
"Carey Carlan" wrote in message
"Arny Krueger" wrote in : "Carey Carlan" wrote in message (Scott Dorsey) wrote in : Make a third disk that is a 48/16 disk but with the levels bumped up by 1 dB. Throw it into the mix. --scott Oh, that's sneaky! I'll do just that. Not sneaky, but an excellent double check. Some listeners just don't get it, and failing to hear a 1 dB (or maybe 2 dB) overall level shift will expose them. If *everybody* fails to detect the 1 dB shift, there could be a problem with the program material that you are using. I've seen normally good listeners falter with program material that jumps around too much or is really unfamiliar. Sneaky in the sense that I've never heard an audio test that didn't prefer the louder signal (within reason). I'm dealing with video people. I don't believe they'd realize that louder has an advantage. Hmmm, while I am a video person of sorts, I was first an audio person... The point is there though - some music makes technical differences far easier to hear than others. For example, while there is little controversy that in general an 11 KHz brick wall filter should be audible, it is possible to find natural program material that makes it hard to detect. OTOH, there are a very few musical instruments that basically sit there and ring strongly around 18 KHz, no matter what notes you play. Just touch them! Most people don't consciously hear the high pitched tone as such, but take it away with a 16 KHz brick wall filter and many listeneners will notice its comings and goings. Does the existance of rare instruments like these justify the need to always carry the bandpass out to 20-22 KHz, or is it reasonable to follow the general rule that holds for almost all music, which is that clean brick wall filtering around 16 KHz is just fine? These are the sorts of things that perceptual coder designers worry about. My philosophy is that I pick reasonable worst case test samples that are reasonably acessible to the people in the US. So, jangling key chains are OK, and a zither would be OK, but odd traditional instruments used rarely in a far corner of a lost province of Spain are not. |
#15
Posted to rec.audio.pro
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The sample rate/bit depth war
On Nov 15, 7:21*am, "Arny Krueger" wrote:
"Carey Carlan" wrote in message I really don't want to start this battle again, but I'm trying to justify to my video counterparts that 48K/16 sampling is adequate for a blu-ray disk that can handle 96K/24. Here's the test I'm planning: 1) Let them choose a blu-ray soundtrack that they think exemplifies the niceties of 96K sampling. 2) Rip that sample bit-accurate into 96/24. By what means that avoids the copy protection? 3) Create an disk from the ripped copy still in 96/24. 4) Reduce the level by 48 dB then raise it back again, effective emptying the bottom 8 bits. Again, by what means? *Emptying the bottom bits with common audio software is not always trivial because they do their work in 32 bit floating point.. My preferred method for emptying the lower bits is actually pretty obvious - convert it to 16 bits and then convert it back to 24 bits. This is basically the methodology described in several recent AES papers including one by John Vanderkooy at the recent San Francisco meeting. 5) Create another disk as in (3) above at 96/24. 6) Have them pick between disks from (3) and (5) in a blind test. By using copies made from the same source using the same steps and playing back in the same machine with the same converters, I should get a fair test. *There is a pass of decompression/recompression when reading/creating a blu-ray disk, but both disks will have the same processing. Anything wrong with this scenario? This has been done many times and the results are that nobody hears a difference unless they do something like listen to very faint passages with high gain settings that would results in excess blasting during the loud passages. Not sure what you mean by not hearing the difference? In my home work, I can hear the difference between recording 44.1/24 and 96/24, particularly with acoustic tracks, on my Sony headphones, with the 96/24 sounding better. Maybe this is because my audio card is of medium quality but I can definitely hear the difference. IMO - if you have a BR, then why not use the higher quality audio? Having said that, I think I might question going to 192. Mike C |
#16
Posted to rec.audio.pro
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The sample rate/bit depth war
"Mr Soul" wrote in message
Not sure what you mean by not hearing the difference? I mean in a level-matched, time-synched, double blind listening test. In my home work, I can hear the difference between recording 44.1/24 and 96/24, particularly with acoustic tracks, on my Sony headphones, with the 96/24 sounding better. Maybe this is because my audio card is of medium quality but I can definitely hear the difference. Like many others, I've tried this sort of thing with some of the finest audio cards, loudspeakers, and headphones around. I've had a goodly number of young, enthusiastic, well-trained listeners try it as well. Post again should you have the resources to try a level-matched, time-synched, double blind listening test. Don't feel like you've been singled out. Everybody sings a different tune after doing a proper blind listening test. |
#17
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The sample rate/bit depth war
Arny Krueger wrote:
Don't feel like you've been singled out. Everybody sings a different tune after doing a proper blind listening test. Not always, in part because there are some lousy converters out there. I have heard one case where the 44.1 audio sounded noticeably better than the same system at 96. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#18
Posted to rec.audio.pro
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The sample rate/bit depth war
I mean in a level-matched, time-synched, double blind listening test.
OK - I see what you mean. In a real scientific test, I have no idea how I would do. However, it my home studio, with material I was familar with, I thought 96/24 sounded better. Why the heck would anyone want to record in 192? Just to waste disk space. That does seem like overkill to me. Mr Soul |
#19
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The sample rate/bit depth war
On 11/16/2010 09:29 PM, Mr Soul wrote:
I mean in a level-matched, time-synched, double blind listening test. OK - I see what you mean. In a real scientific test, I have no idea how I would do. However, it my home studio, with material I was familar with, I thought 96/24 sounded better. The way of testing makes a big difference. You can hardly the placebo effect in such subjective tests. The good news is that you can easily do such tests for yourself. Just get a free abx comparison software like Foobar2000, abx comparator (linux), winabx or pc-abx and check your scores... Cheers, Boris |
#20
Posted to rec.audio.pro
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The sample rate/bit depth war
On Tue, 23 Nov 2010 01:24:45 -0800, Marc Wielage wrote:
If the intended audience is audiophiles who care, then maybe 96/24 a selling point and worth the extra trouble. Good point about this being a marketing issue, not entirely a technical one. Whether or not anyone can hear the difference, there will be some who want to buy 24/96 "because it's better" -- Anahata --/-- http://www.treewind.co.uk +44 (0)1638 720444 |
#21
Posted to rec.audio.pro
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The sample rate/bit depth war
Il 14/11/2010 23.22, Carey Carlan ha scritto:
I really don't want to start this battle again, but I'm trying to justify to my video counterparts that 48K/16 sampling is adequate for a blu-ray disk that can handle 96K/24. Here's the test I'm planning: 1) Let them choose a blu-ray soundtrack that they think exemplifies the niceties of 96K sampling. 2) Rip that sample bit-accurate into 96/24. 3) Create an disk from the ripped copy still in 96/24. 4) Reduce the level by 48 dB then raise it back again, effective emptying the bottom 8 bits. No, you just need to empty the upper 8 bits, the less significative. The best approach is still to TRUNCATE. Otherwise your daw will increase the bithdepth to 32 (at least) and is very hard to get the upper (16) equal to 0 by level adjustments. By the way 48 is not good for this, just 7 bits will be free. the magic number is 48,164799306236991234198223155919 dB, or 49! ;-) 5) Create another disk as in (3) above at 96/24. 6) Have them pick between disks from (3) and (5) in a blind test. By using copies made from the same source using the same steps and playing back in the same machine with the same converters, I should get a fair test. There is a pass of decompression/recompression when reading/creating a blu-ray disk, but both disks will have the same processing. Anything wrong with this scenario? Nothing wrong in this comparision, but DVD and BD are discs. On discs you loose what you don't use, so if the video part don't need more space, feel free to use 96kHz 24bits. Is much more useful to reduce the SR from 96 to 48kHz than the bitdepth! with SR you'll reduce the size by 2 against the bitdepth where you reduce just by 1.5. For the SR part, the blind test is very hard to be made because people don't know where to find differences, but there are still small differencies! 96kHz will give you a better waveform shape on highs. This not always noticeable. 96 make sense if you have a 96kHz recorded sound from the beginning. Upconvert from 48 to 96 is meaningless. The available room on disc and the max allowed program bitrate is the best discriminator in order to take a decision. The bitdepth is much more critical. 24 bits make a very big difference against 16. Always try to use 24 (just a 50% increase in size, but 256 times the dynamic range, 48dB!). Even if your original material is 16, internally, during the processing, the bitdepth is increased to 32 or more (daws) and is better to dither down to 24 at the end of the process. |
#22
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The sample rate/bit depth war
On Mon, 15 Nov 2010 14:32:51 GMT, Carey Carlan
wrote: "Arny Krueger" wrote in : "Carey Carlan" wrote in message I really don't want to start this battle again, but I'm trying to justify to my video counterparts that 48K/16 sampling is adequate for a blu-ray disk that can handle 96K/24. Here's the test I'm planning: 1) Let them choose a blu-ray soundtrack that they think exemplifies the niceties of 96K sampling. 2) Rip that sample bit-accurate into 96/24. By what means that avoids the copy protection? The program is called "AnyDVDHD". 3) Create an disk from the ripped copy still in 96/24. 4) Reduce the level by 48 dB then raise it back again, effective emptying the bottom 8 bits. Again, by what means? Emptying the bottom bits with common audio software is not always trivial because they do their work in 32 bit floating point. Hmm. Correct. In 32 bit, that would be a 96 dB cut and restore. That would be 32 bit fixed-point. In floating point a 96dB cut might just change the exponent (essentially the binary point) and still keep all the significant bits. Not sure of the exponent range, but it's a bother figuring out what floating point range would clip data by how much. My preferred method for emptying the lower bits is actually pretty obvious - convert it to 16 bits and then convert it back to 24 bits. I was trying to avoid any data conversions. By doing nothing but changing levels I might convince others that no magic was happening. Reduce the level by 48dB, write it to a 24-bit external file, load that file, then amplify by 48dB. This bypasses any internal floating-point "magic" that prevents bit depth loss with gain change. |
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