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In Reply to: RE: INTERNET TEST: 24-bit vs. 16-bit Audio. posted by SBGK on April 20, 2014 at 10:01:03
True.. Not internet streaming as some might expect. Too many other variables attached to doing that as well. Besides, that likely would limit most folks to sitting in front of the computer.As for dithering, that's standard anyways for all bit-depth reduction. Plus it adds a bit of noise. Let's just say I'm using nothing fancy at all...
Hope you get a chance to try and respond.
Best regards.
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Archimago's Musings: A 'more objective' audiophile blog.
Edits: 04/20/14 04/20/14Follow Ups:
in every test of up and downsampling I have never found the result to be satisfactory compared with the original, so say I hear a difference - that doesn't prove anything about 16 bit vs 24 bit.
16 bit 96000 hz is an unusual combination, my reference player can't play that.
Another factor is how the dac handles 16 bit in 24 bit containers, this can impart noise of it's own.
Pity you can't get in the same room as people who hear a difference and see if you can hear what they are hearing.
not saying I can tell 16/44 from 24/192, but hirez tracks do sound different maybe because of the mastering, think it's impossible to tell. I'll just continue to listen to what sounds the best.
http://mqnplayer.blogspot.co.uk/
""Pity you can't get in the same room as people who hear a difference and see if you can hear what they are hearing.""
That is the crux of the history of his straw man/trolling.
Cheers,
"Asylums with doors open wide,
Where people had paid to see inside,
For entertainment they watch his body twist
Behind his eyes he says, 'I still exist.'"
This was exactly my point, dithering alters the sound and the change depends on the type and extent of the dither.
I suspect that some inmates have not been exposed to good relockers equipped with dither functions, to Pacific Micronics units such as the Rotel 990, and so on.
Fred, since you are so knowledgeable, please tell us how you would have generated the 16 bit files from 24 bit versions. Would you have used dither? If so, what version and why did you select this one? If no, then why did you make this decision?
The Rotel 990 includes an HDCD decoder. HDCD uses non-standard decoding of 16 bit samples. (The process uses subtractive dither. See linked thread.) The HDCD format offers no sonic benefit over regular PCM unless the special decoder is used. Given that nearly all 16 bit recordings use standard linear PCM encoding and do not require proprietary decoders most people would exclude formats requiring proprietary decoders from 24 bit vs. 16 bit comparisons.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Simple, I would have used different dither schemes to see how close or far apart the files are. If they are close, then post saying so and specifying how dither has been applied (instead of saying that dither has been applied in a couldn't care very much manner). If not, I wouldn't bother with a survey.
Go back to the Rotel, I am not talking about HDCD.
I guess I must conclude from your answer that you have not done the kinds of tests that involve different dithering schemes, otherwise you could easily have given specific answers to my questions.
Your point about the Rotel is, exactly what?
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
I once spent a year playing with the Meridian 518 that leading recording guys like Green Room used and wrote about.
You clearly doesn't know what the Rotel 990 can do wit dither schemes. Go find out first before more questions as my time is valuable.
The Rotel 990 CD player uses the Pacific Microsonics PMD 100 HDCD decoder chip, which provides a number of dither modes. The user interface of the Rotol exposes these to the user. I am familiar with how this chip works, having investigated it several years ago while researching how HDCD works and as part of a general project to understand the theory and practice of dither.
The Rotel user manual is quite terse, but the PMD 100 chip specification provides considerable detail about the dither function. From reading the chip specification and being familiar with the HDCD patents I concluded that there are three reasons why dither might be useful in a product such as the Rotel 990 CD player where this chip is used: 1. The PMD 100 includes a digital volume control When used to attenuate a signal there will be additional bits generated by the multiplications. If dither is not used, this will result in distortion. 2. The PMD 100 includes an HDCD decoder which produces a 24 bit output. If the decoder is being used with a 20 bit DAC chip (as in the Rotel) then there will be distortion added unless dither is applied. 3. The use of dither can improve the sound of multi-bit DACs by causing their low-level errors to be randomized, but this comes at the expense of added noise. Because the last two reasons are specific to a particular product design employing the chip, there are configuration options for dither. As the chip manual describes, the best choice may depend on the converter chip and analog amplifiers further downstream:
Dither Modes
The PMD-100 provides 8 different output dithers in Program mode. All dither levels are available for output data
widths from 16 to 24 bits at 8 Fs and 4 Fs oversampling rates only. Dither must be disabled if the 2 Fs oversampling rate
is selected (as well as 24 bit mode must be selected when the 2 Fs oversampling rate is selected). There are seven levels
of high-frequency weighted dither (modes 0-6) plus minimum amplitude white triangular PDF dither (mode 7). Modes
0 and 7 are minimum amplitude dithers which correct quantizing errors only, whereas modes 1 through 6 are increasing
levels of high-frequency weighted dither designed to smooth out non-linearity errors in multi-bit DAC’s (Modes 0 or 7
are appropriate for single-bit DAC’s). The HF weighted dithers put the dither energy above the audio spectrum, where
most of it is later filtered out by the analog low-pass filter following the DAC. In general, multi-bit DAC’s behave better
with high levels of dither, but some analog circuits following the DAC may have problems with transient intermodulation
distortion (TIM) when confronted with high levels of high frequency energy. The best dither level for a particular circuit
implementation must be determined empirically.
Dither Notes:
1) Dither level 6 is the highest level of high-frequency weighted dither available with the PMD-100.
2) In Stand-Alone Mode, dither mode 0 (minimum high frequency weighted) is available. Setting pin 4 DITH low
will disable all dither including programmed dither and should be used only for test purposes.
The significance of this is that Keith Johnson was well aware that the characteristics of digital signal processing interact with all the downstream analog electronics, including amplifiers as well as converter chips. This means that it is not possible to "optimize" a dither function outside of the context of a particular playback chain. In particular, it is not possible for Archimago to "optimize" the use of dither (or non-use thereof) for a 24 bit to 16 bit conversion. Suggesting or implying otherwise is incorrect and inappropriate. Audiophiles should be aware that their "knowledge" of what is "optimum" is highly specific to the particular components used in their system. Great engineers, such as Keith Johnson, have always known this.
One can approximate all of the dither modes in the Rotel CD player by appropriate configuration of audio editors, so the customary audiophile dismissal is inapplicable: "If you haven't heard product X you are not qualified to comment on this subject."
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
what I said in one line. The Rotel enables dither to be changed according to user preference. It also changes SQ significantly depending on setting.
What was your wobble about?
Perhaps I was too subtle for your mind. I was explaining that I did not have to listen to the Rotel to understand the effects to be heard, as I had already explored these in great detail some time ago.
More important was the explanation provided by Keith Johnson (presumably as he was the brains behind PM) as to how dither choices interact with downstream electronics. Again, nothing new here, but apparently it's not a concept that everyone appreciates, especially those who complain that developers of source components are not properly "optimizing" their products, something that is impossible outside of the context of the complete playback chain. This issue of system interaction is the key to justifying Archimago's choice of simple dither for his experiment.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Quite the opposite and you admitted that the effects can be great.
Subtle in several hundred unrelated words? Ah,mental experiments are of no use in audio.
explains a lot about the bits are bits stance if the premise is that these tracks sound the same.
http://mqnplayer.blogspot.co.uk/
The reason behind my posts is simply this.
Do a survey on some premise; publish the finding on the web, and this becomes fact.
This kind of thing has been a feature of PC audio from the start.
The files are all 24/96. No problem if your DAC doesn't play 16/96.
They were just converted to 16/96 with a little dither (again, nothing fancy!) and then put back into the 24/96 container... That's all... The DAC will not notice any change between tracks.
Listen and let me know if the last 8 bits make an audible difference; remembering of course that there's no DAC on earth that can accurately reproduce those last few bits of dynamic range in 24-bit audio data.
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Archimago's Musings : A 'more objective' audiophile blog.
"Listen and let me know if the last 8 bits make an audible difference; remembering of course that there's no DAC on earth that can accurately reproduce those last few bits of dynamic range in 24-bit audio data."
I believe you will find that there are DAC chips out there that are good to at least 21 or 22 bits when it comes to dynamic range. With DACs using these chips in conjunction with quiet analog electronics at least five or six of the eight low order bits will affect the output. If the highest quality DAC chips are used in parallel then it may be possible to get up to 23 bits with today's chips. Putting extra DAC chips in parallel can improve signal to noise performance, especially if the paralleled chips are fed slightly different digital input so that their individual errors can cancel out. Also, the extra drivers provide more current into the summing resistor and this reduces the thermal noise.
If you have a high gain low noise preamplifier it might be possible to confirm this for your particular DAC by putting the preamplifier in between the output of the DAC under test and the ADC used by your analyzer. Putting the extra gain in would eliminate noise floor issues in your ADC from affecting low level measurements. In this regard it may be helpful to have a DAC that provides a high output level in balanced mode, as this will provide more signal to the preamplifier and ensure that the input stage in the preamplifier does not become the limiting source of system noise. (This is one of the reasons why pro-audio converters use balanced signals and high peak voltages rather than the cheaper methods used with RCA connectors in consumer gear.)
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
listened and found a difference in all 6, 3 were pleasant to listen to and 3 were not so pleasant.
http://mqnplayer.blogspot.co.uk/
''As for dithering, that's standard anyways for all bit-depth reduction. Plus it adds a bit of noise. Let's just say I'm using nothing fancy at all...''
saying this shows that you don't understand the effect of dither and dither functions on sound quality.
The test is useless.
Why does Archimago have to understand the subtleties of dither? He's asking for peoples' listening opinions. The listeners don't need technical details. All they need are their ears.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
it can be a test of how and what dither has been applied.Please explain this: how does hearing a difference with no particular attention paid to dithering depth or function add to the knowledge base on the sound quality of higher versus lower resolution music files?
At best, a survey like this, when published, is likely to add to adisinformation.
Edits: 04/20/14
Consider this: if people could not hear any differences between 16 bit and 24 bit that would have been a good demonstration that there is no benefit in distributing music to consumers in 24 bits. However, given that people have heard differences, one realizes immediately that there is an advantage in sound quality, namely distribute in 24 bits, if only to avoid the possibility that the dither step was done poorly.
One can not use a single set of listening tests to isolate the cause of sonic differences, only to ascertain that there were sonic differences. To attribute a cause one needs a model of possible causes and then one needs to conduct a series of experiments to isolate the cause that accounts for the effects heard. Such an experimental program has to start somewhere, and the obvious one where bit depth is involved is the type of experiment that Archimago has offered. If differences are found, then more exploration can be done to find out if there is a form of dither that would minimize these differences, possibly to the point where most people could not hear them. I think it unlikely that Archimago botched the use of dither in creating his test files. Most audio editing programs have a good implementation of the basic dither as this has been known for decades.
I should think it rather obvious, this being an Asylum, that all of these experiments are just being done for fun and are not likely to end up in a peer reviewed journal.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
Having raised a question and having it answered, I think you are just trying to score points as you often do.
I have better things to do.
What is not acceptable is someone carrying out a survey on questionable premises, as the result will no doubt be publicised as a valid conclusion.
In the past I've questioned the premises behind Archimago's posts and survey's, but in this case I did not do so because I could find nothing wrong with his premises. He does not deserve unwarranted sniping in this thread.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
your 'mastering' expertise claim is suspect.
Okay fmak. I'm not sure if this is all that relevant here. The technical details of how dither "works" isn't that important... Certainly a worthy topic for another thread. It's done as part of reducing bit-depth in any reasonable studio for decades, and that's all I did and will explain the exact setting later.
All I ask is people have a listen and tell me if they think one sounded better. Also how much confidence they have in the choice. It might end up that a person chooses the 16-bit version with confidence with all 3 samples and that'll enter into my analysis as well.
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Archimago's Musings : A 'more objective' audiophile blog.
Just an abusive ad hominem.
If you're saying 'he doesn't understand' something, why don't you splain it to us?
I guess you prefer hit-n-run posts to adding to the conversation.
"The problem with quotes from the internet is that many of them just are just made up."
-Abraham Lincoln
you have no notion of how dither affects sound from a system, you should not be posting like this.
After reading the text linked below, would you still say that fmak's post launches "just an abusive ad hominem", or simply states a basic fact?
The question, of course, becomes whether it's audible in one's system with one's ears - but there's no doubt that, at least theoretically, dithering is not harmless to sound quality.
"The question, of course, becomes whether it's audible in one's system with one's ears - but there's no doubt that, at least theoretically, dithering is not harmless to sound quality."
The absence of dither when it should have been used grossly affects sound quality at 16 bits. A low level sine wave just above the threshold is clearly audible as a clean sine wave with dither, but turns into a square wave without dither. Just below the threshold, a low level sine wave will still be audible above the noise with dither, but will be completely silent without dither. With recordings of acoustic music made in large concert halls one can hear the effect as a musical note fades out in the hall reverberations. With dither, the echos fade smoothly down to and below the noise floor. Without dither, the hall reverberations fade into gross distortion just before becoming abruptly cut off. The same effect occurs with studio recordings that have been manually faded at the end of a track. These effects are readily audible if one listens at natural (concert) volume in a quiet room on a resolving system.
Tony Lauck
"Diversity is the law of nature; no two entities in this universe are uniform." - P.R. Sarkar
dither can extend dynamic range and the final SQ depends on the dither depth and the dither function. Features like the Meridian Mastering Processor and the Apogee UV process apply some or all aspects of these. The effects are easy to demonstrate using a good editing program.
I can't hear a difference. My office setup is Heed Obelisk with a Schiit Bifrost w/analog update and Peachtree D4's with an SVS sub. It's a pretty good little system.
"The problem with quotes from the internet is that many of them just are just made up."
-Abraham Lincoln
Please make sure to fill out the survey, mbnx01. Also invite NY to the test when you see him next.I need more 68 y.o. respondents with musical experience listening to high-resolution audio with a pimped out car stereo.
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Archimago's Musings: A 'more objective' audiophile blog.
Edits: 04/20/14 04/20/14
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