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Audible results from measurements
Yahzi
post Feb 23 2013, 06:08
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Hi there,

The claims I hear for audible differences existing for different electronics amount to frequency response, noise and distortion.

These distortion graphs are between the two I/V stages of a DAC :



And :



The claim is that these DACs measure flat, but the measurements show the effects of certain filters at play. Looking at the distortion components, is this enough of a difference to cause gross audible differences? The claims I hear are that different filters used in DAC design can result in audible differences irrespective if that DAC measured perfectly flat.

What do you think?
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Yahzi
post Feb 26 2013, 15:09
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QUOTE ("Arnold B Kreuger")
It is very true. For example most audio professionals who depend on listening, as they get older they acquire one or more younger engineers that they train how to listen, and then rely on their ears.


Sure, but then one can't really dismiss the claim that they can hear distortion products 100 dB below the fundamental, right? I mean the claim sounds bonkers, but if people can perceive things that others can't, then ...

Unless there any studies of human audibility thresholds that are statistically relevant that show humans can't perceive distortion below a certain point?

This post has been edited by Yahzi: Feb 26 2013, 15:10
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Arnold B. Kruege...
post Feb 28 2013, 20:57
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QUOTE (Yahzi @ Feb 26 2013, 09:09) *
QUOTE ("Arnold B Kreuger")
It is very true. For example most audio professionals who depend on listening, as they get older they acquire one or more younger engineers that they train how to listen, and then rely on their ears.


Sure, but then one can't really dismiss the claim that they can hear distortion products 100 dB below the fundamental, right?


Which they?

You are missing the point. The 100 dB number is better than what the best young listeners can achieve.

QUOTE
I mean the claim sounds bonkers, but if people can perceive things that others can't, then ...


A key part of listener selection and training is monitoring people's sensitivity as compared to other listeners. One of the tests we applied was to look at the individual scores and see if any of the listeners did consistently better. Some people who did consistently poorly were taken aside and encouraged to not participate in the group tests. Some tests were by invitiation and we were careful who we invited, and I mean this in a good way.

When a few people did exceptionally well, we did additional trials with them to see if their results were real or a statistical anomaly. You know if you flip coins, you may get long runs of heads or tails. If you do enough flips, additional flips even things out. Same thing can happen with listeners.

We also had situations where people would do worse than guessing. We watched the tests carefully and noticed that this could happen when the listeners were unconsciously communicating, such as groaning when they were having a tough time hearing differences. One of the things about ABX is that if you are having problems hearing a difference, you generally know it long before you score the test.

Later on I did quite a bit of work with tests involving a known difference that was varied in size. I would start listeners out with large differences, and make the difference smaller in subsequent tests. Eventually, the listeners with working with the natural difference. This made it possible to see who was capable and who was trying versus those who were not trying all that hard or were simply not getting it.

QUOTE
Unless there any studies of human audibility thresholds that are statistically relevant that show humans can't perceive distortion below a certain point?


There are usually a number of different ways to estimate the audibility of a given kind of artifact. You can do different kinds of tests involving the same artifact. Sometimes you can estimate the audibility of an artifact from things like the Fletcher Munson curves or masking curves. In those cases where the same artifact is tested for a number of independent ways, they often give very consistent results.

For example you can estimate the audibility of an artifact using both ABX and ABC/hr tests, which are actually very dissimilar listening tests. The key is that no matter how you present the alternatives or how you ask people to compare them, when they are hearing something their responses correlate with the presence or absence of the stimulus, and when they are not hearing something their responses become random.

There are also other kinds of testing besides presenting samples. You can give people an unmarked knob that varies the level of the artifact, and let them turn it up and down until they feel that they have homed in on the level where it is just audible. This same scheme is used in audiometry - ear tests. It is arguably not exactly double blind, and a creative listener can spoof it, but it can also give very good results.

When people say that a lot of this stuff has been tested to death, they are not kidding!
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Posts in this topic
- Yahzi   Audible results from measurements   Feb 23 2013, 06:08
- - splice   QUOTE (Yahzi @ Feb 22 2013, 21:08) ... th...   Feb 23 2013, 13:11
|- - Yahzi   QUOTE ("splice")It is definitely not ...   Feb 23 2013, 14:09
|- - DonP   QUOTE (Yahzi @ Feb 23 2013, 08:09) QUOTE ...   Feb 23 2013, 16:31
- - Yahzi   I was having a debate with a DAC designer who cite...   Feb 23 2013, 16:42
- - Wombat   QUOTE (Yahzi @ Feb 23 2013, 17:42) Is thi...   Feb 23 2013, 17:29
- - Yahzi   The claim is that the harmonic distortion componen...   Feb 23 2013, 17:42
|- - julf   QUOTE (Yahzi @ Feb 23 2013, 17:42) If you...   Feb 23 2013, 18:09
- - Yahzi   QUOTE They *can* definitely affect timbre, if the ...   Feb 23 2013, 18:23
|- - julf   QUOTE (Yahzi @ Feb 23 2013, 18:23) QUOTE ...   Feb 23 2013, 22:05
- - Yahzi   Sorry, just to add : looking at those graphs, the ...   Feb 23 2013, 18:27
|- - Arnold B. Krueger   QUOTE (Yahzi @ Feb 23 2013, 12:27) Sorry,...   Feb 23 2013, 20:09
- - greynol   Can and do are two different things. Personally, I...   Feb 23 2013, 18:31
- - Arnold B. Krueger   QUOTE (Yahzi @ Feb 23 2013, 00:08) Hi the...   Feb 23 2013, 19:56
- - Yahzi   One of these days I'll book a flight to the St...   Feb 23 2013, 20:44
- - Yahzi   QUOTE ("Arnold B. Kreuger")I've done...   Feb 23 2013, 20:48
|- - Arnold B. Krueger   QUOTE (Yahzi @ Feb 23 2013, 14:48) QUOTE ...   Feb 24 2013, 14:24
|- - Yahzi   This may be a silly question, but in terms of harm...   Feb 25 2013, 13:36
|- - Arnold B. Krueger   QUOTE (Yahzi @ Feb 25 2013, 07:36) This m...   Feb 25 2013, 14:37
|- - DonP   QUOTE (Arnold B. Krueger @ Feb 25 2013, 08...   Feb 25 2013, 18:49
|- - Arnold B. Krueger   QUOTE (DonP @ Feb 25 2013, 12:49) QUOTE (...   Feb 26 2013, 02:04
- - Yahzi   So if I told the DAC designer that his distortion ...   Feb 25 2013, 17:54
- - Yahzi   Sorry Arnold, how do you work out the harmonic per...   Feb 25 2013, 17:57
|- - julf   QUOTE (Yahzi @ Feb 25 2013, 17:57) Sorry ...   Feb 25 2013, 18:31
|- - Arnold B. Krueger   QUOTE (julf @ Feb 25 2013, 12:31) QUOTE (...   Feb 26 2013, 02:06
- - Jplus   The dB scale is logarithmic. 20 dB means a differe...   Feb 25 2013, 18:30
- - Yahzi   What do you guys think of this : "Designers ...   Feb 26 2013, 06:48
- - mzil   It's true some people can hear things others c...   Feb 26 2013, 07:00
|- - Arnold B. Krueger   QUOTE (mzil @ Feb 26 2013, 01:00) It...   Feb 26 2013, 14:49
- - Yahzi   But mzil, just take your time to watch it. It mi...   Feb 26 2013, 07:21
|- - mzil   QUOTE (Yahzi @ Feb 26 2013, 01:21) But mz...   Feb 26 2013, 07:34
|- - probedb   QUOTE (mzil @ Feb 26 2013, 06:34) Worryin...   Feb 26 2013, 14:33
|- - mzil   QUOTE (probedb @ Feb 26 2013, 08:33) QUOT...   Feb 26 2013, 18:06
|- - probedb   QUOTE (mzil @ Feb 26 2013, 17:06) It is a...   Feb 27 2013, 11:52
- - greynol   Tell him you'd like him to disprove the existe...   Feb 26 2013, 07:30
- - greynol   Everything else being equal, the car will have bet...   Feb 26 2013, 07:58
- - Yahzi   Just out of curiosity, did any of you watch the wh...   Feb 26 2013, 10:44
|- - greynol   QUOTE (Yahzi @ Feb 26 2013, 01:44) Just o...   Feb 26 2013, 16:46
- - Jplus   I watched all of it, sometimes pausing to read the...   Feb 26 2013, 13:46
|- - Arnold B. Krueger   QUOTE (Jplus @ Feb 26 2013, 07:46) I watc...   Feb 26 2013, 14:34
- - Yahzi   QUOTE ("Arnold B Kreuger")It is very tru...   Feb 26 2013, 15:09
|- - julf   QUOTE (Yahzi @ Feb 26 2013, 15:09) Sure, ...   Feb 26 2013, 15:57
|- - 2Bdecided   QUOTE (Yahzi @ Feb 26 2013, 14:09) Unless...   Feb 26 2013, 19:35
|- - Arnold B. Krueger   QUOTE (Yahzi @ Feb 26 2013, 09:09) QUOTE ...   Feb 28 2013, 20:57
- - pdq   You may be mischaracterizing whet Arnold said. It...   Feb 26 2013, 15:53
- - greynol   The burden to provide support falls on the people ...   Feb 26 2013, 16:13
- - Wombat   QUOTE (Yahzi @ Feb 23 2013, 17:42) I was ...   Feb 26 2013, 17:14


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