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16 bit vs 24 bit, any samples that work?
AndyH-ha
post Feb 14 2009, 12:46
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The resulting silence was expected. Remember, the tone + silence demonstrations was just my proof-of-concept trial.

In regard to subtracting the 16 bit dither from the converted to 16 bit file, consider two possible variations.

First, instead of converting the dither file to 16 bit to invert-mix with the audio file, convert the audio back to 32 bit, then mix-invert the dither into that (i.e. subtract the original dither). This gives a different result because the audio file is still really only 16 bit of data while the dither has 24 bits. The second half of the tone + silence does not come out silent, although it will have a lower level noise than the dither that was added.

Next repeat the experiment that originally gave silence in the second half of the file but instead of the original dither file, use ay other with noise file of identical specifications. Convert it to 16 bit and subtract. The result is not silence because the ďditherĒ subtracted is not the same data.

Silence only results if the subtraction is of identical data. Staying withing the 16 bit realm, from beginning to end, will produce silence, working with 24 bit data, without converting to 16 bit, will produce silence. Not only the part that started as silence, but also the part of the file that has a signal can be zeroed out completely if all operations stay within the bounds of 16 bit, or 24 bit, where ever we are operating.

Therefore, subtracting the converted-to-16-bit-dither from the dithered-and-converted-to-16-bit audio should completely remove the dither -- except for those tiny values that are the quantization errors of converting the mix of audio and dither to 16 bit. I donít see why one would call it anything other than the conversion quantization error, or why one would expect it to be any more arbitrary than any other quantization error.
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MLXXX
post Feb 14 2009, 16:12
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QUOTE (AndyH-ha @ Feb 14 2009, 21:46) *
Therefore, subtracting the converted-to-16-bit-dither from the dithered-and-converted-to-16-bit audio should completely remove the dither -- except for those tiny values that are the quantization errors of converting the mix of audio and dither to 16 bit. I donít see why one would call it anything other than the conversion quantization error, or why one would expect it to be any more arbitrary than any other quantization error.
I confess I still do not see the purpose of the exercise. If someone wanted to know the extent to which an original file differed from a 16-bit rounded version of it, they could simply subtract the rounded version from the original. Similarly, if they wanted to know the extent to which a dithered 16-bits file differed from the original higher resolution file, they could again simply do a subtraction of those two files.

What you have dubbed the "conversion quantization error' is something else again and I do not understand the significance if it. It will be different for different 32-bit float random dither files employed. It will be a function of the actual dither file, despite some part of that dither file being attempted to be eliminated. It is a creature of calculation and the steps to be followed to create it have been clearly explained, but what in principle it represents, is I'm afraid, still not clear to me.
___________


I hope that Martin (and others) will be giving us the benefit of their ABX reports (+ comments) in the near future on Martin's 24 bit original version versus the dithered 16 bit version at post #145, even if some of those those reports are to the effect that the two versions appear to sound the same.

This post has been edited by MLXXX: Feb 14 2009, 16:12
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Nordenstam
post Feb 14 2009, 21:47
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Hello!

Am one of those others on gearslutz that did 10/10 ABX on the 24 vs HPTPDF 16 bit dither.

The chain was foobar->RME AES32 with asio driver->Lavry DA10. A bit transparent path. The problem with such a setup is that the digital stream can only take one signal at a time. (obviously, being bit transparent). This makes for a disruptive tick sound and a slight interrupt when changing streams between A and B samples. Subtle differences are easier to hear when there's continuos playback. I think it would be easier with two DAC's and a physical ABX unit doing analogue switching. Or, drop the bit transparent path idea and use a software mixer instead. If foobar could send each sound to different output ports, the 40 bit mixer in the RME card could be used and the tick sound/interrupt would hopefully be gone. Providing for that may have an influence on the results.

ABX'ing the 16 bit HPTPDF was not that amazingly hard. I can't say exactly what it is that I'm listening for. It usually changes a few times as the test progresses. When I find a difference to hang on to, it's only good for a few trials until I'm desensitized. Then I have to find another difference, hang on to that until I loose it, and so on. Perhaps the best way to listen is to squint with the ears and simply try to catch the quality of the material. I know this all sounds very vague, but that is exactly the way I listen too, when trying to hear such things. Trying to hear an obvious conscious difference is a sure way to fail. It's a sort of lateral listening.

Could not do the same with either Chris J's special dither or the 24_16_fb2k_dither.wav provided in this thread. So I take it that this is borderline territory. If HPTPDF is audible on this file, better dither may be audible on another file. My favorite for testing such things is to use deep bass sounds, only.. Probably a big no no around here. With such contrived test files, just about any dither should be audible, at least at elevated levels. But I guess that doesn't carry much weight in itself. What I'm trying to get at is that with other pieces of music, better ears/gear/room etc, other 16 bit dithers may be audible too.

As for the differences, just about all 16 bit dithered files can be seen to have more noise than a 24 bit file, when viewed in a spectrogram(like in Izotope RX). Unless the 24 bit source is particularly dirty.


Best regards,

Andreas Nordenstam
(mastering)
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AndyH-ha
post Feb 14 2009, 22:50
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When simply comparing the original with the dithered 16 bit version, the dither is so much greater than any data lost or altered when converting to 16 bit that it is hardly possible to find anything except the dither.

If your other offered possibility, the rounded version, means comparing the original with an un-dithered 16 bit conversion, there will be a great deal of distortion in that 16 bit version that hides any differences in which we may be interested.

The purpose of removing the dither after converting to 16 bit is to be able to see and analyze the difference between 24 bit and 16 bit without dither or distortion confounding the results. Does that offer any insight? I donít know if there is anything beyond the demonstration that the difference is so very small that it is hard to imagine hearing it, or any effect of it, at normal listening volume settings.

The suggestion about using this approach to produce listening samples is to prevent dither noise itself from being the cause of an audible difference, as the most recent ABX success post suggests.

Iím not absolutely certain there isnít something else that Iím missing. That question was the purpose of my posts on the subject.
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MLXXX
post Feb 15 2009, 00:36
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Hi AndyH, perhaps another member will be able to provide confirmation/insight into what the "conversion quantization error" file represents.

QUOTE (Nordenstam @ Feb 15 2009, 06:47) *
Could not do the same with either Chris J's special dither or the 24_16_fb2k_dither.wav provided in this thread. So I take it that this is borderline territory. If HPTPDF is audible on this file, better dither may be audible on another file.
Andreas, thank you very much for this. If we find that Martin cannot successfully ABX the 24_16_fb2k_dither version either, then we appear to be back to square one. That is, with a good dither, the 16 bit dithered version sounds the same as the higher resolution original, for normal recording and listening levels.

As you say, it is possible that another high resolution audio file will lead to an audible difference when well dithered; but at this point in time, it appears no-one has been able to supply such a file.

Thanks again,
MLXXX

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Martin Kantola
post Feb 15 2009, 03:50
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Here's two runs I did today, might try again tomorrow:

foo_abx 1.3.3 report
foobar2000 v0.9.6.1
2009/02/14 20:20:45

File A: C:\Documents and Settings\Valued Customer\Desktop\TEST\samples\24.wav
File B: C:\Documents and Settings\Valued Customer\Desktop\TEST\samples\24_16_fb2k_dither.wav

20:20:45 : Test started.
20:39:06 : 01/01 50.0%
20:43:06 : 01/02 75.0%
20:49:13 : 02/03 50.0%
20:49:37 : 02/04 68.8%
20:49:46 : 03/05 50.0%
20:50:08 : 04/06 34.4%
20:50:32 : 05/07 22.7%
20:50:57 : 06/08 14.5%
20:51:25 : 07/09 9.0%
20:51:48 : 08/10 5.5%
20:53:15 : 09/11 3.3%
20:54:08 : 09/12 7.3%
20:54:56 : 10/13 4.6%
20:55:27 : 10/14 9.0%
20:56:20 : 10/15 15.1%
20:56:44 : 10/16 22.7%
20:56:57 : 11/17 16.6%
20:57:09 : 11/18 24.0%
20:57:43 : 12/19 18.0%
20:57:54 : 13/20 13.2%
20:58:57 : 13/21 19.2%
20:59:08 : 14/22 14.3%
20:59:32 : 15/23 10.5%
21:00:47 : 15/24 15.4%
21:00:59 : 16/25 11.5%
21:01:05 : Test finished.

----------
Total: 16/25 (11.5%)

***

foo_abx 1.3.3 report
foobar2000 v0.9.6.1
2009/02/14 21:14:20

File A: C:\Documents and Settings\Valued Customer\Desktop\TEST\samples\24.wav
File B: C:\Documents and Settings\Valued Customer\Desktop\TEST\samples\24_16_fb2k_dither.wav

21:14:20 : Test started.
21:15:36 : 01/01 50.0%
21:16:42 : 02/02 25.0%
21:17:50 : 03/03 12.5%
21:18:55 : 03/04 31.3%
21:20:18 : 04/05 18.8%
21:21:38 : 05/06 10.9%
21:22:26 : 06/07 6.3%
21:23:40 : 07/08 3.5%
21:24:44 : 07/09 9.0%
21:25:34 : 08/10 5.5%
21:26:57 : 08/11 11.3%
21:27:08 : 09/12 7.3%
21:27:15 : 10/13 4.6%
21:27:26 : 11/14 2.9%
21:27:42 : 11/15 5.9%
21:28:26 : 11/16 10.5%
21:28:52 : 12/17 7.2%
21:29:53 : 13/18 4.8%
21:30:52 : 13/19 8.4%
21:31:37 : 14/20 5.8%
21:33:35 : 14/21 9.5%
21:34:06 : 14/22 14.3%
21:34:39 : 14/23 20.2%
21:35:20 : 15/24 15.4%
21:35:55 : 15/25 21.2%
21:35:58 : Test finished.

----------
Total: 15/25 (21.2%)

Again so easy to get distracted and sidetracked. And my ears get very tired. More about what I think I'm hearing later...

Martin
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2Bdecided
post Feb 15 2009, 22:07
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If you add those together, you get 31/50, which is 5.9% i.e. there's a 1-in-17 chance of getting that purely "by chance". That's pretty good!

The table of these percentages is here:
http://www.kikeg.arrakis.es/winabx/bino_dist.zip

Cheers,
David.

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2Bdecided
post Feb 15 2009, 22:10
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Nordenstam and Martin,

Are you concentrating on the quiet part of the file? Or, to put it another way, can you hear the difference on the loud part of the file?

Common sense suggests it must be the quiet part, but lots of people claim (typically without ABX) that it's equally "obvious" during loud parts.

Cheers,
David.
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Martin Kantola
post Feb 16 2009, 01:32
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QUOTE (2Bdecided @ Feb 15 2009, 16:10) *
Are you concentrating on the quiet part of the file? Or, to put it another way, can you hear the difference on the loud part of the file?


Not listening to the quiet parts. The artifacts seem to be present within the audible part of the music, or actually part of it. It's very interesting, even if the differences are tiny. What it seems to suggest is either that properly dithered music is not 100% perfect even above the 16-bit noise floor, or that our hearing does not work exactly as we first thought...

Another question is, would a very good D to A converter produce better 16 bit audio too (and not only better 24 bit) so that the differences would in fact be smaller on a good system?

Martin
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Canar
post Feb 16 2009, 02:04
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QUOTE (Martin Kantola @ Feb 15 2009, 16:32) *
Another question is, would a very good D to A converter produce better 16 bit audio too (and not only better 24 bit) so that the differences would in fact be smaller on a good system?
Most definitely. The better the DAC, the better the signal. You appear to be hearing a difference, though there is still a reasonable chance that you are not. Even if you are, that just means that the two signals are differentiable on your hardware. Improving (or worsening) your hardware may remove the differentiability.

Are you still doing this test on that laptop?


--------------------
You cannot ABX the rustling of jimmies.
No mouse? No problem.
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Martin Kantola
post Feb 16 2009, 02:38
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QUOTE (Canar @ Feb 15 2009, 20:04) *
Most definitely. The better the DAC, the better the signal.


Thought so. Will do some testing with my favourite DACs when I'm back in my studio. Of course, the rest of the system will have better resolution too.

QUOTE (Canar @ Feb 15 2009, 20:04) *
You appear to be hearing a difference, though there is still a reasonable chance that you are not.


Oh c'mon... Look at the results, the probability of guessing was down to less than 3% during the second run. I'm not that lucky :-) But it sure was difficult with this dither.

QUOTE (Canar @ Feb 15 2009, 20:04) *
Even if you are, that just means that the two signals are differentiable on your hardware. Improving (or worsening) your hardware may remove the differentiability.


Obviously I can't try all brands and models of hardware... But how likely is it that it's only on this specific Sony laptop with these headphones that one can hear a difference? Remember that I tried truncated + three different flavors of dither so far.

Martin

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2Bdecided
post Feb 16 2009, 11:31
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QUOTE (Martin Kantola @ Feb 16 2009, 01:38) *
Oh c'mon... Look at the results, the probability of guessing was down to less than 3% during the second run. I'm not that lucky :-)
It doesn't work like that. Those percentages are the stats for that point in the test if that was the point you pre-decided you were going to stop before the test commenced.

The chance of hitting "5%" at some point during the run are far higher than 5%. Similarly, if you start testing, with the intention of stopping when you reach "5%", the chance of hitting "5%" is higher than 5%!

Calculating the actual stats for that (it's called a "sequential ABX") are difficult, and depend on the conditions. There's an excel spreadsheet about it here...
http://www.hydrogenaudio.org/forums/index....st&p=151958
...so if you intend to do 25 runs, and you'll count <5% (the "0.95" column in that table) at any point as a "pass", the chances of passing somewhere in 25 attempts are 11.2%, or about 1-in-9.

If you want to run sequential ABX tests, you need to aim for <1% to be sure the actual chance is <5%.


I'm posting simply to clarify that particular part, not to say you didn't pass. I've already said that I think you "almost" passed - just not because the displayed value dipped below 5% at some point.

Cheers,
David.

P.S. original (non-sequential) ABX stats thread:
http://www.hydrogenaudio.org/forums/index....showtopic=14679
Calculator that doesn't do any stats, it just simulates random ABX and says how many passes there are:
http://ff123.net/abx/abx.php
(obviously it matches the stats, but it was useful in proving the stats are correct)
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MLXXX
post Feb 16 2009, 13:40
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QUOTE (Martin Kantola @ Feb 6 2009, 10:28) *
Remember that I was listening on my crappy laptop setup with very low level on the phones, so had to listen to changes in timbre and not in low level detail or similar.

QUOTE (Martin Kantola @ Feb 10 2009, 04:12) *
I can try ABX:ing with this shitty setup, but I'd much rather get deeper into the testing when I'm back in my studio with proper gear, where I'll be able to measure the SPL used too.

QUOTE (Martin Kantola @ Feb 16 2009, 11:38) *
Will do some testing with my favourite DACs when I'm back in my studio. Of course, the rest of the system will have better resolution too. ... Obviously I can't try all brands and models of hardware... But how likely is it that it's only on this specific Sony laptop with these headphones that one can hear a difference?

Hi Martin, at this point in time you are the only person to report an ABX verified difference between 24.wav and 24_16_fb2k_dither.wav

It will be quite an important result if you can also report an ABX verified result using equipment other than the "crappy laptop setup". It would be useful too if you could comment on where in the file the difference is most noticeable, and what the difference sounds like.

QUOTE (Martin Kantola @ Feb 10 2009, 04:55) *
Don't think the 24 bit standard is only a result of clever marketing. There must have been a lot of testing at low (or normal) level among people who developed all these converters and software.

There is plenty of evidence 24-bits are useful for recording and mixing. That is not in dispute. However, there is remarkably little, if any, evidence that 24 bits are actually needed for distribution of the final mix to the consumer, compared with a noise shaped dither. (I might mention that a related and contentious question, whether 96KHz sampling might be audibly superior to 48KHz sampling, is not part of the subject matter for the current thread. It's a separate minefield!)

Cheers

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Martin Kantola
post Feb 16 2009, 16:31
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QUOTE (2Bdecided @ Feb 16 2009, 05:31) *
QUOTE (Martin Kantola @ Feb 16 2009, 01:38) *
Oh c'mon... Look at the results, the probability of guessing was down to less than 3% during the second run. I'm not that lucky :-)
It doesn't work like that. Those percentages are the stats for that point in the test if that was the point you pre-decided you were going to stop before the test commenced.


Don't worry, I've understood how it works ;-) But that temporary low number shows that I was making the right choice several times in a row, which was when I felt I had 'tuned in' on the difference. It has no statistical value or significance, but hopefully illustrates how important the focusing part is of ABX listening. If I could manage to stay focus all the time my score would improve.

Martin
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Martin Kantola
post Feb 16 2009, 16:56
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QUOTE (MLXXX @ Feb 16 2009, 07:40) *
It will be quite an important result if you can also report an ABX verified result using equipment other than the "crappy laptop setup".


Will certainly do that as soon as I can. Would also like to involve others in the testing, to see if I can help them spot the difference by discussing it before the test.

QUOTE (MLXXX @ Feb 16 2009, 07:40) *
It would be useful too if you could comment on where in the file the difference is most noticeable, and what the difference sounds like.


What I listened for was the upper, 'air' region of the frequency response. The 16 bit seems to be slightly rounded off and lack detail. The highest frequencies produced by the strings is a good thing to focus on. In general I thought the 16 bit sounded a bit dampened and maybe even grainier, but not enough to help me with the ABX.

QUOTE (MLXXX @ Feb 16 2009, 07:40) *
There is plenty of evidence 24-bits are useful for recording and mixing. That is not in dispute.
As a sound engineer, I understand these benefits. But remembering the first time I had a chance to try 24-bit recording, it was not hard to appreciate the difference even on a single file without any processing and such. But of course, there was an upgrade in converters involved too.

The reason I think 16 bit format works so well for consumers is that the mastering engineers make them sound as good as possible, and are actually able to compensate for the tiny losses we discuss here, even with simple EQ. After all, music is to be enjoyed, not analyzed.

Like I might have mentioned before, the reason I'm still interested in the subject is that if we can show that 24 vs 16 bit is detectable at normal volumes, how does the lowered resolution affect us on a long-term and subconscious level? Is the CD sound less emotionally exciting than it could be? To me, well recorded music does transfer some 'energy' contained in the information and not only sound waves.

Martin
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krabapple
post Feb 17 2009, 04:17
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QUOTE (Martin Kantola @ Feb 15 2009, 20:38) *
Oh c'mon... Look at the results, the probability of guessing was down to less than 3% during the second run. I'm not that lucky :-) But it sure was difficult with this dither.


It doesn't work that way, sorry.

As things stand, you haven't yet breached the p<0.05 threshold, much less the p<0.01 threshold that some would argue is more appropriate for this phenomenon.

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Martin Kantola
post Feb 17 2009, 04:56
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QUOTE (krabapple @ Feb 16 2009, 22:17) *
It doesn't work that way, sorry.


Already said I knew that :-)

QUOTE (krabapple @ Feb 16 2009, 22:17) *
As things stand, you haven't yet breached the p<0.05 threshold, much less the p<0.01 threshold that some would argue is more appropriate for this phenomenon.


While I understand the importance of a probability threshold, don't see the point of me personally trying to satisfy those numbers. Instead I'd like to see more people getting similar results, to learn more if there's indeed something to this. Not trying to provide final scientific proof at this point, only make a suggestion which should be followed by more and better controlled testing.

It's really hard to hear the difference, that's simply why I can't breach the threshold. It's not necessarily because it's inaudible. Only a machine can deliver the same result time after time. Don't get me wrong, I've recently found ABX and I'm very excited about the possibilities, it seems to be a very effective way to rule out one's own beliefs. But I sincerely hope you're not saying that only p<0.01 would make this worthwhile discussing further?

Martin
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MLXXX
post Feb 17 2009, 12:10
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QUOTE (Martin Kantola @ Feb 17 2009, 01:56) *
What I listened for was the upper, 'air' region of the frequency response. The 16 bit seems to be slightly rounded off and lack detail. The highest frequencies produced by the strings is a good thing to focus on. In general I thought the 16 bit sounded a bit dampened and maybe even grainier, but not enough to help me with the ABX.


A few comments:-

1. Where perceived differences are very small, suspicion develops that the playback equipment may be solely responsible. For example, the very slightly higher total high frequency energy in the dithered version could be trigerring a small power drain in the laptop audio system: unlikely but possible. It will be more convincing if/when the results can be replicated by Martin on other equipment.

2. If the higher frequencies of the strings is where the difference is most noticeable, perhaps another recording of strings can be found to show the effect more obviously, permitting others to hear it.

3. Those well versed in the mathematics of dither may cringe at this, but I have always thought it unlikely that dither would be found ineffective for the lower signal frequencies. Intuitively, high frequency dither provides an ample number of random variations per cycle of a low frequency sine wave signal for a clearly defined instantaneous "moving average value" to emerge that defines a value between adjacent discrete steps in the 16 bit quantisation; for the purpose of driving a woofer, or a mid-range speaker in its lower frequency range [and independent of any sophisticated technique of waveform reconstruction].

4. The effort required to hear the difference apears to be considerable. Even if people other than Martin end up hearing differences, if that is only through intense concentration then the differences may not be "material". It might be that money would be better spent on things such as replacing recording microphones with more advanced microphones, or using better loudspeakers, than releasing recordings at 24-bits rather than 16-bits dithered. [However, we are really still at point number 1, above, i.e. waiting for tests on other equipment or by other people.]

5. Occasionally when I listen to a section of 24.wav it seems to sound a little crisper than the corresponding section of 24_16_fb2k_dither.wav, but my ABX results are hopeless. I cannot differentiate the two files with any degree of reliability. The two files are for practical purposes, for myself, identical.
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2Bdecided
post Feb 17 2009, 15:22
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Re: point 3...

yes, but, Martin first ABXed it with bog standard 16-bit TPDF dither, no noise shaping. I then added another 8 bits of noise to get it back to 24-bits. He still "nearly" ABXed it. I can't think of an equipment issue that would cause an audible difference between real 24-bit and 24-bit with the bottom 8 bits noise.

FWIW the other comments I've heard about 16-bits vs 24-bits is that it sounds "grungy".

Cheers,
David.
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botface
post Feb 17 2009, 18:50
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I've just posted something in another thread but I think it's relevant here too.

I'd love to see some ABX results. A lot of the listening tests that people refer to here are done on headphones - because it's easier to spot artifacts that way - but most music is not mastered with headphone listening in mind. I'm more interested in finding out if somebody can spot differences over speakers that aren't evident over headphones. Martin, did you say you were going to use studio gear for your comarison? Would that mean speakers?I look forward to seeing some results
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Martin Kantola
post Feb 17 2009, 19:29
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QUOTE (botface @ Feb 17 2009, 12:50) *
Martin, did you say you were going to use studio gear for your comarison? Would that mean speakers?


Definitely. Not sure when I can get to that proper testing, could be as late as April, but I'd be happy to report back as soon as I've done some. One factor that might make it more difficult with speakers is small head movements. Speaker distortion is another of course. But the general resolution of the system will be much better, so it'll be interesting to see how it works out.

Martin
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krabapple
post Feb 17 2009, 20:17
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QUOTE (botface @ Feb 17 2009, 12:50) *
I've just posted something in another thread but I think it's relevant here too.

I'd love to see some ABX results. A lot of the listening tests that people refer to here are done on headphones - because it's easier to spot artifacts that way - but most music is not mastered with headphone listening in mind. I'm more interested in finding out if somebody can spot differences over speakers that aren't evident over headphones. Martin, did you say you were going to use studio gear for your comarison? Would that mean speakers?I look forward to seeing some results


If anything, I'd expect loudspeaker listening to be less conducive to discriminating differences than headphone listening...not more. What differences might be evident over them that wouldn't be evidence over loudspeakers ? (Assuming loudspeakers and headphones of comparable FR.)

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botface
post Feb 17 2009, 20:37
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QUOTE
If anything, I'd expect loudspeaker listening to be less conducive to discriminating differences than headphone listening...not more. What differences might be evident over them that wouldn't be evidence over loudspeakers ? (Assuming loudspeakers and headphones of comparable FR.)


I'm not expecting any specific differences but I don't listen via phones and since most music is mastered to be listened via speakers - as far as I'm aware - it seems a more relevant comparison to me
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AndyH-ha
post Feb 17 2009, 22:39
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The listening experience of headphones is quite a bit different than loudspeakers. Of necessity, I do my LP transfers using headphones, and in some ways that might be easier, but various small percussion instruments, and some other transients, can be hard to distinguish from vinyl noise at times on the headphones. It isnít that these sounds are less audible, they are just distinctly different.

Every once in a while I have to write my work to CD so I can use the living room system. Sounds that I was very uncertain about keeping are suddenly revealed very clearly to be, for instance, two wood sticks being struck together. Sounds of some other instruments sound as though they are really being produced by those instruments but on headphones it is nowhere near so clear.

Another thing: background noise, such as hiss or vinyl wear noise, will seem fully acceptable on headphones but very intrusive on the speakers. That I decide more NR is necessary after listening on speakers is obviously a personal preference, but the differences in sound, headphones to speakers, is pronounced. Then there is the fact that the sound stage and room ambience are not really there on headphones.

Some might believe this all indicates defective equipment but I donít think so. The soundcard and headphone amplifier are good. Iíve used Sennheiser HD600s, Grado SR125s, Sony MDR-V900s and V6s, and occasionally others. All sound different from each other, but none are poor quality. Iíve discussed this with audio and acoustical engineers; it seems to be well know, accepted, and considered more or less explained. Mixing and mastering people rarely consider headphones to be of any value for their work.

None of this says that differences would be undetectable on one and detectable on the other, but the fact hardly seems obvious. Much music really sounds ďbetterĒ to me on the speakers, but I still enjoy headphone listening; for some kinds of music I prefer the headphone experience.

I canít think of how it would be possible to ABX test headphones against speakers, there are too many obvious clues as to which one is using. Unfortunately I also canít do audio file ABX testing in the living room, and I have no intention of spending whatever it would take to allow me to operate a computer from my listening chair. These difficulties might lead some to maintain that differences are unproven, but it hardly seems reasonable to deny all experience that one cannot substantiate by tests.
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Martin Kantola
post Feb 17 2009, 23:02
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QUOTE (MLXXX @ Feb 17 2009, 06:10) *
1. Where perceived differences are very small, suspicion develops that the playback equipment may be solely responsible.


Always possible, but not very likely, I'd like to think that the playback equipment makes it even more difficult in this case. Why do you think these artifacts would not be tiny? After all, we're messing with a few LSBs here...

QUOTE (MLXXX @ Feb 17 2009, 06:10) *
2. If the higher frequencies of the strings is where the difference is most noticeable, perhaps another recording of strings can be found to show the effect more obviously, permitting others to hear it.


Great idea! Hoping to record another clip specifically for testing.

QUOTE (MLXXX @ Feb 17 2009, 06:10) *
4. The effort required to hear the difference apears to be considerable. Even if people other than Martin end up hearing differences, if that is only through intense concentration then the differences may not be "material". It might be that money would be better spent on things such as replacing recording microphones with more advanced microphones, or using better loudspeakers, than releasing recordings at 24-bits rather than 16-bits dithered.


Microphones are my main field, so I agree that they are very important and where we should spend most of the money :-) As for why this digital issue matters, it's because of two reasons IMHO:

a) what's assumed about audibility and human perception must constantly be updated, especially when it comes to anything nonlinear or discrete.
b) 16 bit PCM is hopefully not the final word in music or audio, and we need to learn more about what a better format should look like.

QUOTE (MLXXX @ Feb 17 2009, 06:10) *
The two files are for practical purposes, for myself, identical.


Thanks for listening. It's very difficult to hear, wasn't joking... But we know for a fact the files are not identical, so the question is can we learn how to focus on and detect the difference well enough to get reliable ABX results. There are so many other factors at play than the files themselves, our listening environment to begin with.

Martin

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