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Hydrogenaudio Forum => General Audio => Topic started by: icstm on 16 March, 2012, 07:31:57 AM

Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 16 March, 2012, 07:31:57 AM
SOME THOUGHTS

All this talk about skin “hearing” music, “feeling” the vibrations of the music etc raises for me a separate debate.

Whilst I completely agree that ABX is an excellent tool for spotting consciously detectable differences (ie respondents must be wilfully aware of the difference to make their choice) what about our unconscious decisioning? Just the other day their was a BBC documentary “out of control” which they were explaining how your unconscious mind is often calling the shots and influencing the decisions you make.

So we have 3 different types of tests:
1)   Signal waveform analysis (as was used to check to see if JPlay was doing anything or FLAC v WAV using Audio DiffMaker
2)   ABX audio testing (man in the middle) for checking for conscious discrimination of different samples
3)   Enjoyment factor (or some other form of what some philosophers call qualia)


I am not saying to know that our skin reacts to sound or anything like that however I can believe that there is more to our enjoyment of music than just what our ears hear, for example I was at a classical concert yesterday and we slipped from the back to some seats in the front where we could feel the power of the music more in our bellies. Is this just due to the increased volume and would our ears have provided our brains with sufficient information if I had desensitised my stomach – I am not so sure. Now clearly in this example I was conscious of this effect, but there may be others I was not and yet still added to my overall enjoyment.

So even assuming that enjoyment is a wholly conscious act there could be unconscious inputs that the brain turns into conscious states. However these states could be impacted by the ABX test in 2 ways:
A.   Not enough time is allowed for in playing the samples for these unconscious inputs to take effect
B.   The act of enjoying a concert vs the act of trying to spot differences mean the brain is trying to do different things and thus doing the second might not require the same inputs as used in the first (I assume we are happy that the outputs of those 2 exercises are likely to be different and in a different form

Now bear in mind that for this thread I am in the 16/44 is sufficient for playback camp – I am still saying I am not fully satisfied that tests (1) and (2) are sufficient to provide complete proof. It is a bit like evolution (as some other poster mentioned). There is some proof for the theory, there are many wholes (for example in the fossil line) however there is no proof for any other theory...
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: dhromed on 16 March, 2012, 07:56:57 AM
I was at a classical concert yesterday and we slipped from the back to some seats in the front where we could feel the power of the music more in our bellies. Is this just due to the increased volume[?]


Yes.

It is a bit like evolution (as some other poster mentioned). There is some proof for the theory, there are many wholes (for example in the fossil line) however there is no proof for any other theory...


Implying that audio testing is just as vague as evolution does a gross disservice to both fields.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Speedskater on 16 March, 2012, 08:24:40 AM
In a really good ABX test:

First] The listener should by very familiar with the sound of both products before the start of the test.

Second]  While the most sensitive tests (JND) are usually done with very short samples,  the listener should be permitted to listen to each product for as long as they wish.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: pdq on 16 March, 2012, 08:32:27 AM
Don't assume any limitations to how ABX testing is applied. The only real limitation is that it needs to be applied double-blind, i.e. there can not be any means other than the effect being tested to differentiate A from B from X.

Your reference to conscious decisions isn't even a limitation. There is no reason that the subject even be aware that he is taking an ABX test if the observer can evaluate his reactions without them being verbalized. Similarly there is no requirement that the testing be within some time period. Testing could take place over months or years and still be just as valid.

Finally, I will point out what has been said many many times before. ABX testing cannot prove that there is no difference between A and B. It can only provide reasonable certainty that there is.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 16 March, 2012, 09:10:13 AM
I was at a classical concert yesterday and we slipped from the back to some seats in the front where we could feel the power of the music more in our bellies. Is this just due to the increased volume[?]

Yes.
but that does not answer how exactly that increased volume is captured by the brain

Your reference to conscious decisions isn't even a limitation.
(1) There is no reason that the subject even be aware that he is taking an ABX test if the observer can evaluate his reactions without them being verbalized.
(2) Similarly there is no requirement that the testing be within some time period. Testing could take place over months or years and still be just as valid.
I really like both of these and both of these were in my head when I wrote the first post. However what I could not decide is how I capture the results from the tests and how and when I ask for their answers.

However I disagree with your statement that I have now put in bold. My reasoning is as per my first post. What you do with your suggestions goes someway to address the problem, but we need some other way of capturing responses for a comparison
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: pdq on 16 March, 2012, 09:20:10 AM
There are many ways that one could envision determining a subject's response without asking him/her. Just off the top of my head, someone may subconsciously avoid coughing if one is enjoying what one is listening to. Count how many times the subject coughs in a certain time period and use that as the basis of the test.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: KMD on 16 March, 2012, 09:25:20 AM
I agree that  being engrosed in a listening experience and trying to spot the difference between two sources is a different application of the intellect.


-
Owen.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 16 March, 2012, 09:31:07 AM
pdq -
I agree that there should be a way to measure it, I am just not clear on the specifics that will work for our cases.
As I said in the now OP, I am comfortable assuming we are interested (at least at this stage) is conscious stages of mind, even if these are driven from unconscious inputs. So I "know" that I am happy, even if I don’t know what exactly I am experiencing to make me happy.

ABX is looking at a different conscious stage, rather than "I am happy" it is looking at "I am spotting a difference". We can agree that it is possible for 2 different samples to trigger the second in the specific for of "I am spotting a difference in these 2 samples". Whereas you seem to be wanting to use it to also answer the first. I suggest that this is really the second state in a different form "I am spotting a difference in the happiness state created by these 2 samples". This is slightly different from what we wanted to measure.

That is the act of us comparing our own happiness states actually changes our state of mind which could be stopping us conducting the measurement we actually wish to measure.

Your example of coughs is an example of a world we could explore to get around this, but as I started off this reply by saying, I am not clear on the approach we should take.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: KMD on 16 March, 2012, 09:36:39 AM
How about adding market discipline to an ABX test. At the end of the test the participants are invited to purchase one of the sources. I'm liking that.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Arnold B. Krueger on 16 March, 2012, 09:46:03 AM
I was at a classical concert yesterday and we slipped from the back to some seats in the front where we could feel the power of the music more in our bellies. Is this just due to the increased volume[?]

Yes.
but that does not answer how exactly that increased volume is captured by the brain


There is this book named "This is Your Brain on Music".  Answers your question.

Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Arnold B. Krueger on 16 March, 2012, 09:51:03 AM
I agree that  being engrosed in a listening experience and trying to spot the difference between two sources is a different application of the intellect.


That said, faulting bias controlled listening tests on the grounds that there is a difference between them and a listening experience at a live venue (obviously true!) is an example of a false comparison.

Nobody brings a pair of speakers to a venue, and compares them to the live performance, except maybe guys like me who record them. Then we mostly use headphones for pretty obvious reasons.

If you want to compare ABX to something relevant, compare it to a listening comparison done at a dealer's or a friend's.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: KMD on 16 March, 2012, 10:00:09 AM
I  wasn't refering to a live venue. By listening experience I meant exactly that, the act of enjoying and being engrosed in something that may be the subject of an ABX test.



Owen.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Porcus on 16 March, 2012, 10:20:35 AM
Don't assume any limitations to how ABX testing is applied. The only real limitation is that it needs to be applied double-blind,


The ABX test method and the double-blindness are distinct concepts. The former is a type of experiment, the latter is a method to address and mitigate a certain type of bias. You can have double-blind experiments that are not of the ABX type, and you can have ABX with or without double-blinding. Question is rather, which one(s) of these four combinations (ABX or not, double-blind or not) it makes sense to use.

If we are facing the issue of use of A/B tests which are prone to placebo-type bias, then a very modest request for improvement would be: Suggest the smallest possible blinded (i.e. 'blindable'!) modification to sighted A/B. The mitigation of placebo is an end, the double-blinding is a well-established means to that, and ABX is ... well, basically iterated comparison, so it passes as a small modification to AB. Problem solved.

(In addition to 'ABX in place of A/B' and 'double-blind', this forum also would expect a standard to statistical procedure to evaluate the scores before drawing inference from them. That is a third distinct concept!)


i.e. there can not be any means other than the effect being tested to differentiate A from B from X.
[...]
Testing could take place over months or years and still be just as valid.


Ah, well, in principle. In practice, you could easily violate the ceteris paribus desideratum, and it would be hard to get sensible results. There is an entire branch of the statistical science dedicated to the design of experiment.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: pdq on 16 March, 2012, 10:33:35 AM
I only mention testing over longer periods to counter the usual argument against ABX that it doesn't take into account long-term effects. If the length of the test is too short to take into account long-term effects then that is a limitation on how the test was applied, not in the methodology itself. Clearly it would be difficult to avoid other variables if the testing period were as long as years although random variation of the stimulus would help to alleviate that.

Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: drewfx on 16 March, 2012, 11:52:03 AM
SOME THOUGHTS
So even assuming that enjoyment is a wholly conscious act there could be unconscious inputs that the brain turns into conscious states.


One prime example of a proven and often unconscious input is expectation bias.

So the big problem is if you suppose that there are things that are perceptible only unconsciously and that can't be determined through ABX/DBT, how do you test for them with any reliability?

And if you can't get any sort of reliable evidence, does it make sense to suppose that such things really exist? Based on what?

You can certainly theorize that something might possibly exist, but should also ask, "How likely is it that something is only unconsciously perceptible in ways that specifically and effectively evade detection in controlled testing?".
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 16 March, 2012, 12:16:16 PM
@drewfx I think you are missing what I am saying. I am not saying that "there is a flying spegetti monter or a tea pot orbiting the moon it is just we cannot see them". I am simply saying that there is a chance that ABX/DBT where the listener is having to make a choise is not the right way to verify the unconscious elements.

As KMD says, listening for enjoyment and listening for a test are 2 different exercises. We (I) would like to know a method that can measure the difference between 2 samples when the listener is trying to listen for enjoyment. Maybe a EEG, maybe something else, but I would like to know.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: KMD on 16 March, 2012, 12:22:13 PM
icstm - yes an EEG filts in with my idea of how "engrosing" a stimulus is. Seeing as MP3 is based on perceptial encoding  what is meant by perception  for mp3 must be well documented.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: drewfx on 16 March, 2012, 12:46:54 PM
I am simply saying that there is a chance that ABX/DBT where the listener is having to make a choise is not the right way to verify the unconscious elements.


But you are supposing here that there are (or might be) otherwise undetectable unconscious elements. My point was, based on what?

It seems to me you are trying to improve the testing procedure to catch test cases that might not exist. Now that's not necessarily a bad thing, as ideally testing would catch everything conceivably possible.

But in the case of audio, it plays into the belief many people out there have (and I definitely don't mean to imply you're one of them) that "ABX/DBT is flawed in just such a way that it can't detect all this stuff that I know I can hear!".

So I think we need to keep that in perspective.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Arnold B. Krueger on 16 March, 2012, 01:11:31 PM
Don't assume any limitations to how ABX testing is applied. The only real limitation is that it needs to be applied double-blind,


The ABX test method and the double-blindness are distinct concepts. The former is a type of experiment, the latter is a method to address and mitigate a certain type of bias. You can have double-blind experiments that are not of the ABX type, and you can have ABX with or without double-blinding. Question is rather, which one(s) of these four combinations (ABX or not, double-blind or not) it makes sense to use.

If we are facing the issue of use of A/B tests which are prone to placebo-type bias, then a very modest request for improvement would be: Suggest the smallest possible blinded (i.e. 'blindable'!) modification to sighted A/B. The mitigation of placebo is an end, the double-blinding is a well-established means to that, and ABX is ... well, basically iterated comparison, so it passes as a small modification to AB. Problem solved.


The above paragraph pretty much describes our state of mind when we invented ABX. 

Our first attempt involved creating a hidden list of As and Bs that were assigned randomly before the test and maintained throughout the test.

We'd play the alternatives in accordance with the hidden list and ask people to respond by writing down on a personal piece of paper first which one they liked the most, and later on whether they thought that List Item N was A or B.  We made this change of direction because people complained that they thought they could hear a difference, but the alternatives were too much alike to create a preference.

This was found to be too hard because it put too much burden on our memory for the subtle details of what things sounded like.

Then we provided sources known to be A and B as references that the listener could compare to the unknown (which we started calling X) as many times as desired.  That was ABX and it always seemed to be wonderfully easy compared to what went before it.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Porcus on 16 March, 2012, 02:20:58 PM
The above paragraph pretty much describes our state of mind when we invented ABX.


 

I tried to be very careful not to make any claims on precisely what was actually intended or thought when it originally came about (or when it found its way into this forum's terms).

(And I actually wrote, but deleted before submitting, that I think ABXing is very modest indeed, as the typical mode of the unscientific layman (and the ingorant professional) would be to 'compare A to B and report the difference'. I was totally unaware that you actually attempted a higher level of ambition first. But this goes into a pet principle of mine as a ... well, professional geek: if you  try to explain differences, don't forget to check whether there is one. Otherwise, be aware that you are basically doing what-if analyses (which is perfectly fine, for example for precautionary purposes, as long as you are aware of it).)
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: googlebot on 16 March, 2012, 03:16:18 PM
If your primary listening situation is sighted, and not blind, and if seeing the music coming from a nicely furbished, expensive amp & HD source alters your perception of the sound, go for it! That alteration is real and modern science would not disagree. You will very likely not be able to tell it apart from a regular CD player and amp, when blindfolded, but you are usually not going to be listening while being blindfolded. So what?
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: saratoga on 16 March, 2012, 04:02:22 PM
As KMD says, listening for enjoyment and listening for a test are 2 different exercises. We (I) would like to know a method that can measure the difference between 2 samples when the listener is trying to listen for enjoyment. Maybe a EEG, maybe something else, but I would like to know.


Unless you believe that you're somehow more sensitive to artifacts when listening for enjoyment then actively looking for artifacts, I don't see that it matters.  If I concentrate and have a reference and still hear nothing, then I am quite confident that under my normal listening conditions I will also hear nothing.  I think its universally true that differences become more apparent under an A/B comparison, not less.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Porcus on 18 March, 2012, 10:04:10 AM
If your primary listening situation is sighted, and not blind, and if seeing the music coming from a nicely furbished, expensive amp & HD source alters your perception of the sound, go for it! That alteration is real and modern science would not disagree. You will very likely not be able to tell it apart from a regular CD player and amp, when blindfolded, but you are usually not going to be listening while being blindfolded. So what?


I have a better suggestion:
I am fairly certain that the FIFO buffer makes my DAC immune to any jitter from my $chickens**tmoney digital output. Knowing that the mumbojumbo segment of self-proclaimed audiophiles will have spent $$elephantsize on some oversensitive ill-constructed DAC, just because it 'reveals all the differences' between digital outputs, and then spent $$mammoth on a dejitter/reclock box which basically has a RAM the size of a 90's telephone, that gives me the pleasure of 'Gawd, what a bargain knowledge can buy' any time I hook up to my fb2k, and if I want to listen to Mahler or funeral doom, I can switch to 'heck, what has mankind come to be?'.

I know I shouldn't pull a 'my placebo is better than your placebo' without supplying the ABX logs to prove it, so let me stick to 'your placebo is not better than mine, and mine is much cheaper'. 
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: googlebot on 18 March, 2012, 10:40:01 AM
I am fairly certain that the FIFO buffer makes my DAC immune to any jitter from my $chickens**tmoney digital output.


It's nice, that a simple FIFO component is able to boost your musical enjoyment and assurance.  It certainly is placebo, though. A FIFO can buffer samples, but the clock rate must still be reconstructed from the S/PDIF input signal, and is thus prone to jitter. S/PDIF doesn't transmit timing information as a discrete value but implicitly and eventually analog.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: splice on 18 March, 2012, 07:17:51 PM
...  the clock rate must still be reconstructed from the S/PDIF input signal, and is thus prone to jitter.  ...


Er... not directly. The output clock is derived from the state of the FIFO buffer. It does vary slowly, but short-order intersample variations on the clock derived from the input S/PDIF signal are effectively suppressed. Consider the FIFO as a low-pass "jitter filter" with a cutoff frequency set by the size of the FIFO.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 19 March, 2012, 07:59:31 AM
BACK TO MY OP
How does THIS  (http://jn.physiology.org/content/83/6/3548.full)page change things?
It is from The American Physiological Society Journal of Neurophysiology.

It is 10 years old, so there maybe some newer studies.
It shows that the brain can responde to high-frequency components (HFCs) above the audible range, but I would want to know what impact this has on our conscious states.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: greynol on 19 March, 2012, 08:03:20 AM
A search of the forum should have revealed that the topic has already been discussed. As such I don't see the need to have it here as well.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 19 March, 2012, 09:55:04 AM
ah, did not realise that it was the much discredited work that I have seen referenced in other treads. Thanks for pointing out.

Has anyone else tried to replicate in terms of using EEG and PET scans? It seems sensible. It would be great if this has been done and the results are negative.

EDIT: further reading the old threads here it makes me wonder why this discussion in general has not be closed down? Is it for the reasons of my evolution analogy, ie there is evidence (allbeit incomplete) that there is NO difference when listening to this 24/192 recordings, however, even though there is no real evidence to support their position, because there is no evidence irrefutably prove that there is no difference they carry on?

For me I would ideally like to see something along the lines of a set of EEG or PET scans.
I saw some great scans that were taken whilst musicians were playing known pieces of music vs inprov and showed different parts of the brain at work - so I am sure they should be able to find a difference if there was one for our purposes.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: DonP on 19 March, 2012, 10:09:41 AM
Has anyone else tried to replicate in terms of using EEG and PET scans? It seems sensible. It would be great if this has been done and the results are negative.


If the argument is that the process of  ABX test is too distracting, I doubt a PET scan will fly.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 19 March, 2012, 11:09:24 AM
yeah, I was thinking about that too. Plus they are quite noisey machines...

So what can we do? I need some sort of remote analysis!
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Arnold B. Krueger on 19 March, 2012, 11:56:12 AM
...  the clock rate must still be reconstructed from the S/PDIF input signal, and is thus prone to jitter.  ...


Er... not directly. The output clock is derived from the state of the FIFO buffer. It does vary slowly, but short-order intersample variations on the clock derived from the input S/PDIF signal are effectively suppressed. Consider the FIFO as a low-pass "jitter filter" with a cutoff frequency set by the size of the FIFO.


Agreed.

This technology has to work, because the above methodology how every CD player contend with the often egregiously jittery digital data that comes off of the CD itself.  Nothing new, either. I first saw this method work on IBM computer tape drives in the 1960s, and it was old technology then!
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Porcus on 19 March, 2012, 02:04:23 PM
...  the clock rate must still be reconstructed from the S/PDIF input signal, and is thus prone to jitter.  ...


Er... not directly. The output clock is derived from the state of the FIFO buffer. It does vary slowly, but short-order intersample variations on the clock derived from the input S/PDIF signal are effectively suppressed. Consider the FIFO as a low-pass "jitter filter" with a cutoff frequency set by the size of the FIFO.


Agreed.

This technology has to work, because the above methodology how every CD player contend with the often egregiously jittery digital data that comes off of the CD itself.


While I have always assumed buffers to 'work' much in the sense that keeping the buffer roughly half-full, allows the next stage time to adjust slowly yet timely (which I have guessed is precisely what we want), I still don't really know what could go 'wrong' about this. In principle, it could run overfull and cropping off a sample, which would probably be less audible than running empty. But how would these issues sound on the borderline between total failure (i.e. no bits to wait for) and barely running? Could the 'scratch-scratch-schz-schz' type sound from badly damaged CDs be it?

(I guess somebody will jump the chance to say that such a question merely illustrates the that the problem is bogus ...)
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: googlebot on 19 March, 2012, 03:04:30 PM
Er... not directly. The output clock is derived from the state of the FIFO buffer. It does vary slowly, but short-order intersample variations on the clock derived from the input S/PDIF signal are effectively suppressed. Consider the FIFO as a low-pass "jitter filter" with a cutoff frequency set by the size of the FIFO.


Sounds nice, but the clock is usually recovered by a phase locked loop. When you feed this directly into an common DAC you can still measure slight amounts of jitter at the output. Reclocking is usually only found in rather expensive or exotic audio gear.

You can get rid of the jitter completely if you just save the buffer's output to your hard disk and play it back later at a fixed rate, e. g. at 44.1kHz (you could call that manual reclocking). The buffer mechanism you describe has nothing to do with clock recovery. The FIFO is not emptied in a constant rate, but in bursts, no clock signal is recovered at this stage. And refill speed is determined the PLL recovered input clock. You can also get rid of the input jitter by letting your sound card push samples at the PLL derived rate into a memory buffer and then empty the buffer at a chosen output sample rate.* And that's indeed possible, but not what is usually happening, neither in regular playback hardware nor software, in contrast to what your simplification suggests.

I'm not claiming that this is relevant in terms of audibility. But arguing from an objectivist perspective has enough credible aspects already (e. g. demanding double blind proof). IMHO you don't support the cause by denying inaudible, but measurable, imperfections of common playback paths with oversimplification.

* Using the PLL recovered clock as you master guarantees zero data loss due to clock differences (no clock is perfect). Pulling at a fixed rate will loose data here and then, again probably inaudible most of the time, but still a property one usually does not want in a digital system.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Arnold B. Krueger on 20 March, 2012, 09:38:06 AM
Er... not directly. The output clock is derived from the state of the FIFO buffer. It does vary slowly, but short-order intersample variations on the clock derived from the input S/PDIF signal are effectively suppressed. Consider the FIFO as a low-pass "jitter filter" with a cutoff frequency set by the size of the FIFO.


Sounds nice, but the clock is usually recovered by a phase locked loop.

When you feed this directly into an common DAC you can still measure slight amounts of jitter at the output. Reclocking is usually only found in rather expensive or exotic audio gear.


According to the manufacturer's data sheet the TI PCM2707 USB DAC chip includes a PLL and a FIFO buffer.

TI PCM 2707 data sheet (http://www.ti.com/lit/ds/symlink/pcm2707.pdf)

Fully assembled USB DACs incorporating this chip sell on eBay for under $70.

EBay offering (http://www.ebay.com/itm/MUSE-DA20-Top-quality-PCM2707-USB-DAC-Nice-Mini-DAC-/110714815648#ht_4435wt_1163)

I don't think this is an exceptional part, but similar to competitive parts from other sources.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 20 March, 2012, 11:48:37 AM
A PLL is to sync to signals to the same clock, whereas a FIFO buffer is a buffer - why wouldn't you have both?
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: pdq on 20 March, 2012, 12:37:48 PM
The amount of filtering that you can apply to the PLL is proportional to the amount of buffering that you provide. There is no reason that the PLL filter can't be fast enough that zero buffering is needed, but obviously this affects the amount of input jitter that can be tolerated, as well as the amount of output jitter.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Arnold B. Krueger on 20 March, 2012, 01:09:19 PM
SOME THOUGHTS

All this talk about skin “hearing” music, “feeling” the vibrations of the music etc raises for me a separate debate.

Whilst I completely agree that ABX is an excellent tool for spotting consciously detectable differences (ie respondents must be wilfully aware of the difference to make their choice) what about our unconscious decisioning? Just the other day their was a BBC documentary “out of control” which they were explaining how your unconscious mind is often calling the shots and influencing the decisions you make.

So we have 3 different types of tests:
1)   Signal waveform analysis (as was used to check to see if JPlay was doing anything or FLAC v WAV using Audio DiffMaker
2)   ABX audio testing (man in the middle) for checking for conscious discrimination of different samples
3)   Enjoyment factor (or some other form of what some philosophers call qualia)


In really long-term ABX tests, several of us have noticed that we tend to forget that we are doing an ABX test, and then remember it. The wake up call to self from self goes something like this:

Oh, by the way you are supposed to be doing an ABX test, and the display says X so are we still having fun?

How remote from the actual sensing part of the evaluation do we have to get before we can believe that our sensing adequately engaged our unconscious thoughts?
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 22 March, 2012, 07:36:19 AM
If you are forgetting that you are doing an ABX, then I think you are basically there! But how often does that happen?

I would have thought to do an ABX you would need to be listening to the same track in the same room, so when you say long-term, how do you accomplish it?
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: greynol on 22 March, 2012, 09:31:45 AM
http://www.hydrogenaudio.org/forums/index....st&p=789697 (http://www.hydrogenaudio.org/forums/index.php?s=&showtopic=94050&view=findpost&p=789697)

...rinse and repeat(?).
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 22 March, 2012, 12:04:06 PM
@greynol
You've lost me there, Arnold was providing an example where people had forgotten they were doing an ABX test. Drewfix's post simply misses the fact that doing something under "test" conditions is different from other conditions. What Arnold's example seems to suggest is where someone had got to the point where they forgot they were in test conditions.

It is a bit like an unatural interview improving once the subject forgets the camera is there.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: greynol on 22 March, 2012, 12:59:53 PM
I guess I'd like to see you answer drewfx's point and points of others who I believe rightly suggest that distinguishing differences requires critical listening over casual listening rather than dismiss them.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: drewfx on 22 March, 2012, 01:05:07 PM
Drewfix's post simply misses the fact that doing something under "test" conditions is different from other conditions.


There's a difference between saying that there are things we perceive unconsciously/subconsciously and asserting that those things can only be perceived unconsciously/subconsciously.

If you're driving down the street you might not consciously notice a red car with the windows rolled down parked on the left (along with a lot of other stuff), but that doesn't mean you couldn't see it if you were looking for it.

The question I'm asking is whether there is any evidence that there are "audible" things that are real and not imagined and can only be noticed unconsciously/subconsciously and/or outside of ABX testing?

Or are we discussing a theoretical possibility that such things could possibly exist and thus should be tested for?
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: greynol on 22 March, 2012, 01:23:29 PM
To take this further, someone investing time and/or money towards this endeavor will only likely do so if you adequately address drewfx's first question.  If you can only say yes to drewfx's second question then I think you're out of luck.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Arnold B. Krueger on 22 March, 2012, 07:08:37 PM
If you are forgetting that you are doing an ABX, then I think you are basically there! But how often does that happen?


YMMV

Quote
I would have thought to do an ABX you would need to be listening to the same track in the same room, so when you say long-term, how do you accomplish it?


Nothing special. Just leave the equipment hooked up and powered up and use it normally. The hardware ABX box had a battery backup for its memory so that if you lost power during a long-term ABX, you could just restart the same test when the power came back.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Arnold B. Krueger on 22 March, 2012, 07:12:15 PM
I guess I'd like to see you answer drewfx's point and points of others who I believe rightly suggest that distinguishing differences requires critical listening over casual listening rather than dismiss them.


I'd like to see Drewfx answer the following question, which I think needs to be answered before his.

How do you reliably know that you unconsciously perceive something that you are not conscious of during the test, and possibly never conscious of?
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: dhromed on 22 March, 2012, 07:46:53 PM
How do you reliably know that you unconsciously perceive something that you are not conscious of during the test, and possibly never conscious of?

Is that question mostly rhetorical?
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: greynol on 22 March, 2012, 08:26:13 PM
Here we go again with the flying spaghetti monster.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: drewfx on 22 March, 2012, 09:06:00 PM
I'd like to see Drewfx answer the following question, which I think needs to be answered before his.

How do you reliably know that you unconsciously perceive something that you are not conscious of during the test, and possibly never conscious of?


I'll be happy to answer that:

My answer is that I don't know, and I don't particularly care about stuff I can't consciously perceive until someone shows me a good reason why I should.  I tend to care more about stuff I can actually consciously perceive. YMMV
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: greynol on 23 March, 2012, 01:03:15 AM
Because of my masochistic tendencies, I had to go back over and look at the title that was provided to the topic after it was most certainly going to derail a topic that was deserving of better and zeroed in on the word happiness which prompted me to search for the thread where some people wouldn't accept that fact that ABX tests do not have to have time limits.

http://www.hydrogenaudio.org/forums/index....showtopic=38041 (http://www.hydrogenaudio.org/forums/index.php?showtopic=38041)

Spoiler alert: there is nothing in this discussion that can't also be found there.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: 2Bdecided on 23 March, 2012, 05:30:32 AM
Spoiler alert: there is nothing in this discussion that can't also be found there.
So true. So often. Maybe we need to get out more? Or stop trying to fix the world one audiophile at a time?

Cheers,
David.

Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 23 March, 2012, 07:44:44 AM
If you're driving down the street you might not consciously notice a red car with the windows rolled down parked on the left (along with a lot of other stuff), but that doesn't mean you couldn't see it if you were looking for it.
but what if their door opened and without realising you took corrective action. So not only did your brain register the car (your example) but your brain also took some action (my addition). Then this would be interesting. And I am pretty sure this happens, as there have been many times when drivers get someone and cannot remember exactly how they did.
Or are we discussing a theoretical possibility that such things could possibly exist and thus should be tested for?
Theoretical in this space possibly, but we have examples, like the one above which show the brain can do exactly this.

@greynol does this show that there is a chance for the spaghetti monster here?
Maybe I am misunderstanding the conditions of an ABX test, but as I said in the OP or early on, there are definite states of mind in which we take certain inputs and get different ouputs. After all we are a Mealy machine of sorts. So unless you are saying that doing an ABX test and just listening for enjoyment are one and the same state (which Arnold was suggesting can almost happen) then you can get different outcomes.

And I saying that we DO get different outcomes? Do I believe that this is likely? - No, but I have to admit it would NOT surprise me if it was shown that there was something that we hadn’t yet considered.


Remember again either from my OP or near the top, I am interested in a conscious outcome. It is no good that an unconscious input leads to no changes in our conscious awareness (ie we swerve the car and even in retrospect do not realise we did so) we are only interested when we are changed in our consciousness. I am comfortable that ABX can test of overt changes in consciousness, however there are 2nd order changes in consciousness that a) it is harder to pin point what caused the change and b) we be hard to replicate

Now with ABX, it actually circumvents the problem with (a), but does not address (b). So in my initial example around “happiness” forcing someone to be happy is rather difficult.

However I now seem to have done full circle in re-articulating why I think this is worthwhile and in the process only Arnold has provided an example of how when he felt he could make that 2nd order call.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 23 March, 2012, 07:51:21 AM
@greynol
There was a post in that old thred you pointed to that says:

Quote
The point of double-blind testing is to make sure that you're getting goosebumps over something you actually hear, and not something you expect to hear. The whole point is to try to evaluate what you're hearing without knowing whether it's the original or the lossy encode. That shouldn't remove the "emotional" part of it, just make sure that you're reacting based upon something that is really there, and not what you want to hear or what you expect to hear.

The problem is that if I am expecting to be shocked / amazed / surprised I actually end up less shocked / amazed / surprised.
I want to be able to measure how much someone enjoyed the music experience without them knowing beforehand that they are going to be doing this analysis, as knowing that they are going to analyse changes what their objective whilst listening to the music
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: greynol on 23 March, 2012, 12:13:22 PM
Are we expected to believe the more consciously attentive driver would not have spotted the car with the open door?

Anyway, if you think that a test of the unconscious mind will show that it influences how the conscious mind responds to differences in stimulus that the conscious mind cannot detect on its own, devise a test and have at it.  Unlike you, I would be surprised if such a test was anything other than a waste of time.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Porcus on 23 March, 2012, 12:29:26 PM
Could a signal just above the hearing threshold cause temporary 'dull hearing' (presumably, most noticeable one octave lower)?



Oh, by the way, <derail>
https://lh3.googleusercontent.com/-W5H-fLcy...al-illusion.jpg (https://lh3.googleusercontent.com/-W5H-fLcy6Og/TuSEeq7g34I/AAAAAAAAAas/7wZ_-fxgxUk/demotivational-posters-optical-illusion.jpg)
</derail>
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: drewfx on 23 March, 2012, 04:10:15 PM
I'd like to see Drewfx answer the following question, which I think needs to be answered before his.

How do you reliably know that you unconsciously perceive something that you are not conscious of during the test, and possibly never conscious of?

In an attempt to have some fun last night, I was a bit flippant in my "I don't know and I don't care" response.

Upon reflection, it occurred to me that the difficulty in easily answering this question tends to show that there's no known evidence of such things - if any test had been done that produced credible evidence, just explaining that test's methodology would be the answer here.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 26 March, 2012, 09:42:08 AM
I agree, but nor have I seen evidence for any tests.
I would happy just to know that the tests have been done and there is nothing to report.
I am not saying that it is not unlikely that the brain does not provide a different response in ANY way to a signal higher than 16/44. However, a) there is no theorem that shows that there is nothing in the brain that CANNOT respond to signals better than 16/44 and b) nor is there empirical evidence that the whole brain cannot respond (only, and I use the word only loosely, that we do not respond consciously when consciously looking, as shown through DBT ABX tests).
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: greynol on 26 March, 2012, 10:01:47 AM
Should I start binning appeals to the flying spaghetti monster?
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 27 March, 2012, 05:41:39 AM
but we have satellites and telescopes that would have shown some proof of flying spaghetti monsters by now.
We also have EEG/fMRI and other scans that could show a difference.
Actually I wish I have thought of that 6 months ago - a friend had some time with a fMRI for some research he was doing nearly every day for about 6 weeks - I am sure we could have run some tests then.

What I have now decided is that even though I am only interested in some conscious state change, given that DBT/ABX shows that no consciously perceptible change results in a conscious state change, then if we can show that there is no change in unconscious response to those samples, there can be no conscious stage change due to unconscious responses.

What techniques were used to design perceptual encoders?

Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: DonP on 27 March, 2012, 09:06:49 AM
We also have EEG/fMRI and other scans that could show a difference.


Given the noise, possible claustrophobia, and reported direct stimulation of nerves by MRI machines, I don't see how it would be a good tool for measuring subliminal sound effects below the threshold that ABX could.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: 2Bdecided on 27 March, 2012, 09:14:39 AM
This "subconscious perception" is a red herring icstm. Audiophiles regularly claim to hear night-and-day differences in sighted A/B listening tests, that vanish under the scrutiny of a properly controlled double blind test.

To then fall back on "subconscious perception" is to look in an entirely different place. The strong conscious belief was either due to conscious perception, or placebo. Where sighted test = difference heard, and otherwise identical but double-blind test = no difference heard, we know what was heard in the first test. We don't need to look any further.

If "subconscious perception" sold audiophile equipment, then I guess there would be genuine interest in it (real or not). But when placebo sells it so much better, there's no need

Cheers,
David.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: googlebot on 27 March, 2012, 02:19:38 PM
That placebo can cause a significant effect on the human body could be shown in clinical trials. Subjects believing to receive active agents reacted differently from subjects knowingly receiving placebos.

I wouldn't wonder, when the belief of what kind audio source you are listening to can alter your perception measurably (medical variables) vs. a double-blind test. So these people aren't necessarily hopeless fools, they are just reporting what they are genuinely perceiving.

PS:

I also wouldn't wonder, when a music lover listening to his/her hand-selected high-end system, is able to reach higher levels of musical enjoyment and satisfaction than an objectivist with an ABX-proven conviction, that said system is not distinguishable from his onboard-codec, feeding his China made, plastic-enclosed D-AMP.

I do not claim that the latter is necessary.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: greynol on 27 March, 2012, 02:29:00 PM
So these people aren't necessarily hopeless fools, they are just reporting what they are genuinely perceiving.

I don't know that any of the regular participants in these types of discussions disagree with you on this.  I certainly don't.

I also wouldn't wonder, when a music lover listening to his/her hand-selected high-end system, is able to reach higher levels of musical enjoyment and satisfaction than an objectivist with an ABX-proven conviction, that said system is not distinguishable from his onboard-codec, feeding his China made, plastic T-AMP.

...and I wouldn't wonder if some objectivist is able to reach higher levels of enjoyment than some audiophile with high-end equipment. I still wouldn't wonder even when the audiophile is focusing on the actual music rather than his high-end gear.

FWIW, I was getting chills listening to some new music in mp3 format on my crappy PC speakers.  I would gladly put my level of enjoyment during that session up against anyone with a high-end system.

Hopefully my testimonial illustrates the uselessness of this type of subjective argumentation.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: greynol on 27 March, 2012, 02:44:22 PM
but we have satellites and telescopes that would have shown some proof of flying spaghetti monsters by now.

I hope I am not the only one who sees the irony in this.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: googlebot on 27 March, 2012, 03:03:55 PM
I have stopped arguing with audiophiles in my social network, when I



None of them got there by double-blind testing, but by spending a fortune on ordering stuff (that they had read about in very subjective reviews) and actually extensively testing it in their houses.

None of my friends, who are believing - as I mostly do - that AAC should be enough for everybody, own a system of comparable playback quality. Probably because they just do not share this fetish or mental condition to feel the constant urge to project something into their audio equipment. But if I just compare the results empirically, by means of overall system playback quality, the "subjectivists" frequently win by far.

That they still often rather deserve our pity than indignation, because they are pursuing what money and playback technology can't buy, is another story...

Just my 2 cents. I'm somewhat getting tired of those "lets make fun of another fool who doesn't believe in double blind testing"-threads (not this one).
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: greynol on 27 March, 2012, 03:21:35 PM
None of them got there by double-blind testing, but by spending a fortune on ordering stuff (that they had read about in very subjective reviews) and actually extensively testing it in their houses.

Which doesn't address the other perhaps more crucial part of the problem: the limitations in the human auditory system and its certain deterioration with age.

None of my friends, who are believing - as I mostly do - that AAC should be enough for everybody, own a system of comparable playback quality. Probably because they just do not share this fetish or mental condition to feel the constant urge to project something into their audio equipment.

They are probably not inclined to train themselves to identify artifacts resulting from lossy encoding either.

I'm somewhat getting tired of those "lets make fun of another fool who doesn't believe in double blind testing"-threads (not this one).

Obviously not this one.  For me this one is about the lengths people will go bending over backwards grasping at straws in order to deny that what they're experiencing is placebo effect, plain and simple.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Woodinville on 27 March, 2012, 06:28:13 PM
A blog I wrote on the psychology behind this issue is up at audioskeptic.blogspot.com 

It wasn't intended for this audience, so it's very, very gentle on the science, but it none the less makes the point.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: JJZolx on 27 March, 2012, 09:30:07 PM
Just my 2 cents. I'm somewhat getting tired of those "lets make fun of another fool who doesn't believe in double blind testing"-threads (not this one).


Same here.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Nessuno on 28 March, 2012, 04:39:25 AM
Hopefully my testimonial illustrates the uselessness of this type of subjective argumentation.


Just my two eurocents: I completely agree, and since long I've made up my mind about this matter: through listening, both objectivists and subjectivists may reach a kind of superior enjoiment of which the musical content is only part of the whole. Good for them everytime they can, here at HA we are (should be?) only strictly concerned about musical reproduction as a matter of fact, not about other tricks one might use to better enjoy his/her life, though... 
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Porcus on 28 March, 2012, 05:15:35 AM
I was getting chills listening to some new music in mp3 format on my crappy PC speakers.  I would gladly put my level of enjoyment during that session up against anyone with a high-end system.


What about those of us who are happily attending concerts mixed in almost mono by some old fart 'sound engineer' who first turned semi-deaf when he saw The Who, played too loud for the room, filtered through highly nonlinear earplugs, and to cap it all we are sharing the event with lots of drunk idiots who will be shouting during quiet parts and otherwise trying to include you in their goddamn moshpit?

... and we even pay more for the tickets than for the CD.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 28 March, 2012, 06:06:09 AM
We also have EEG/fMRI and other scans that could show a difference.


Given the noise, possible claustrophobia, and reported direct stimulation of nerves by MRI machines, I don't see how it would be a good tool for measuring subliminal sound effects below the threshold that ABX could.

I completely agree that this is a likely limitation and posted as such some posts earlier. However I still think it shows that there are tools at our disposal.

To then fall back on "subconscious perception" is to look in an entirely different place. The strong conscious belief was either due to conscious perception, or placebo. Where sighted test = difference heard, and otherwise identical but double-blind test = no difference heard, we know what was heard in the first test. We don't need to look any further.

I agree that the group you refer to have not offered up any meaningful information to support their case. In fact I think we have concluded that to date this is no (or almost no) evidence that supports their case that this forum has come across.

but we have satellites and telescopes that would have shown some proof of flying spaghetti monsters by now.

I hope I am not the only one who sees the irony in this.
only if you beleive that we have trained our equipment to look in the right places.

Look I am not a biologist, but an engineer by training, so like block diagrams...

1. Real world inputs
|
|
V

2. Transducers on our sensors (eyes, ears, etc)
|
|
V

3. Central nervous processing
|
|
V

4. Brain processing
|
|
V

{5a. low order Conscious decisioning and control (unrelated example – choosing the order of words to type)
& 5b. unconscious decisioning and control (unrelated example – typing words you know how to type and spell already)}
|
|
V

6. Conscious decisioning, feedback
|
|
V

7. emotional states


Maybe this picture is wrong which is why I am at odds with people in this thread.
So I am happy to be corrected, however if it is right then what I am suggesting is that:

A) Waveform analysis can compare different signals (to decide if there are variations in (1) [answer there can be]
B) ABX checks for differences in 5a
C) Depending on what you want to do in (6) your final state in (7) may be different

We have not tested 5b and if 5b can impact 7 (or indeed (6)) then this is an omission that should be observed, even if we believe it to be insignificant.
I am not saying that I think it is significant and that only greynol at al. think otherwise, I am truly saying that I do not think it will radically change our view of these other music formats, however it will surely improve our understanding all 7 stages of the end to end process.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: knutinh on 28 March, 2012, 06:33:28 AM
If it cannot be registered, cannot make reliable predictions and in no other way seems to affect man kind, then it may not matter much, and

If e.g. prescence of energy above 20kHz affect our sub-concious state, but not our conscious state, I would think that an experiment can be done where one or several audiophiles receive a playback system that will remove HF for long periods of time, then re-introduce it. One could try to estimate the emotional state of the listeners by direct questioning ("are you happy today? More than last week"), and/or by indirect indicators such as amount of sleep. This would make it a (more) purely psychological experiment, and perhaps more competence could be found in such societies.

I don't think that such an experiment would show anything besides noise, and I prefer to spend my lifetime doing things that I believe is worthwhile. If true "happiness" is what we aim for, investigating the emotional impact of different shape and colors of your loudspeakers, the use of alcohol, how to maintain good social relations etc might be more rewarding.

-k
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Woodinville on 28 March, 2012, 03:39:43 PM
[We have not tested 5b and if 5b can impact 7 (or indeed (6)) then this is an omission that should be observed, even if we believe it to be insignificant.
I am not saying that I think it is significant and that only greynol at al. think otherwise, I am truly saying that I do not think it will radically change our view of these other music formats, however it will surely improve our understanding all 7 stages of the end to end process.


My goodness, please see audioskeptic.blogspot.com

What you are missing is what can,and what can not, be detected at all on the auditory periphery.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 29 March, 2012, 05:15:51 AM
What you are missing is what can,and what can not, be detected at all on the auditory periphery.
yes I that is exactly right, I am not clear what the response curves are on the auditory periphery. How have we measured this? And by measured, I do not mean asked subjects, I mean where have we done the equivilent of sticking a probe just past the transducer.

Nice set of posts btw, just taken a look.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: 2Bdecided on 29 March, 2012, 06:10:30 AM
I mean where have we done the equivilent of sticking a probe just past the transducer.
I can't wait to hear the answer to this one.

I know about the experiments on live cats (there's plenty of published data), but I'd never even dreamt the idea that someone would do it to a human.

It's been done on cadavers, but a lot of the sensitivity (and all of the adaptability) of the ear dies with its owner.

Cheers,
David.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 29 March, 2012, 06:55:31 AM
I mean where have we done the equivilent of sticking a probe just past the transducer.
I can't wait to hear the answer to this one.

Did you mean to type that, or was that something between a Freudian slip or your NLP preference?
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Woodinville on 29 March, 2012, 09:06:42 PM
What you are missing is what can,and what can not, be detected at all on the auditory periphery.
yes I that is exactly right, I am not clear what the response curves are on the auditory periphery. How have we measured this? And by measured, I do not mean asked subjects, I mean where have we done the equivilent of sticking a probe just past the transducer.

Nice set of posts btw, just taken a look.


It's not just "response curves", the SNR of a given inner hair cell (which is the detector) is about 30dB, which is mapped over about 90dB by the compression provided by the outer hair cell.

Of course, an inner hair cell responds only to signals that actually make it move, and the cochlear filter is 70 to 80 Hz in bandwidth at low frequencies, and about 1/4 octave at higher frequencies.

As far as "sticking a probe", it would appear you are asking someone to be seriously wounded in order to determine this in a human being, so let's stop with that foolishness.

As far as "asked subjects", can you explain what your problem with a proper subjective test might be?  Such tests are verifiable, repeatable, and falsifiable, and provide the same result over and over and over again, and have from the 1930's to present.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Woodinville on 29 March, 2012, 09:09:23 PM
It's been done on cadavers, but a lot of the sensitivity (and all of the adaptability) of the ear dies with its owner.

Cheers,
David.


Quite so, the cochlea (basilar membrane in particular) is an active organ, and the filter shapes change substantially after death. None the less, subjective experiments provide a good measure of the ear's filter bandwidth and SNR at any given instant.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 30 March, 2012, 05:25:39 AM
As far as "sticking a probe", it would appear you are asking someone to be seriously wounded in order to determine this in a human being, so let's stop with that foolishness.
I think the answer is simple - namely that when you are testing a system, you want to understand the inputs and ouputs of each module. "asking" someone would be a response to stage 6 or so in my simple (and probably wrong) model. In either case it is too late in the system.

I did not mean actually using a giant probe, I meant using a sensor to test earlier in the chain.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Woodinville on 30 March, 2012, 04:09:03 PM
As far as "sticking a probe", it would appear you are asking someone to be seriously wounded in order to determine this in a human being, so let's stop with that foolishness.
I think the answer is simple - namely that when you are testing a system, you want to understand the inputs and ouputs of each module. "asking" someone would be a response to stage 6 or so in my simple (and probably wrong) model. In either case it is too late in the system.

I did not mean actually using a giant probe, I meant using a sensor to test earlier in the chain.


Sorry, you aren't understanding even the basics of how auditory perception has been shown to work, or how to probe a system response in general.

Look up "signal detection experiment" for starters, how about?
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 02 April, 2012, 05:23:03 AM
@Woodinville
You are right, I am not well versed in Signal Detection Theory, and indeed there must be many other theories that given your background in this space, you will be able to educate me and others about. The point of this thread is not for me to point out something that I know that others do not, but more to explore 'aloud'/in public what we know about these effects.

From what I have now read about SDT and the memories it has jogged of the courses I did study, it appears to help explain the science behind overt decision making, an ABX perhaps, rather than an understanding of what is happening before we have fully processed our perception of signal and noise to make a determination.

Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Kees de Visser on 02 April, 2012, 06:40:17 AM
I did not mean actually using a giant probe, I meant using a sensor to test earlier in the chain.
There are methods that don't hurt, but AFAIK they are mostly used to diagnose hearing loss and are probably not accurate enough for our purpose.
http://en.wikipedia.org/wiki/Auditory_brainstem_response (http://en.wikipedia.org/wiki/Auditory_brainstem_response)
Quote
The auditory brainstem response (ABR) is an auditory evoked potential extracted from ongoing electrical activity in the brain and recorded via electrodes placed on the scalp.
...
The ABR is used for newborn hearing screening, auditory threshold estimation, intraoperative monitoring, determining hearing loss type and degree, and auditory nerve and brainstem lesion detection.
[/size]
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: greynol on 02 April, 2012, 12:29:46 PM
From what I have now read about SDT and the memories it has jogged of the courses I did study, it appears to help explain the science behind overt decision making, an ABX perhaps, rather than an understanding of what is happening before we have fully processed our perception of signal and noise to make a determination.

The point (at least in part) is that one needs to be aware of whether the portion of the signal in question even makes it far enough along to be processed by whatever level of conscious state.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Woodinville on 03 April, 2012, 04:20:57 AM
From what I have now read about SDT and the memories it has jogged of the courses I did study, it appears to help explain the science behind overt decision making, an ABX perhaps, rather than an understanding of what is happening before we have fully processed our perception of signal and noise to make a determination.

The point (at least in part) is that one needs to be aware of whether the portion of the signal in question even makes it far enough along to be processed by whatever level of conscious state.


Indeed, and then it is possible to move on to level-roving experiments, and see how a layer of memory and its time-extent can be defined, then move on to more complex features, and see how long their memory lasts, and so on.

This is, of course, not all discussed in one place, it's a summary of 1000's of experiments and lots and lots of reading, gathered over 40 years of working in the field. I realize that's hard to convey in a few paragraphs.

I was thinking about writing a book, but I kind of like being retired, too...
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 03 April, 2012, 05:44:43 AM
The point (at least in part) is that one needs to be aware of whether the portion of the signal in question even makes it far enough along to be processed by whatever level of conscious state.
bingo! So if we have a good knowledge of this, then that provides excellent information.

Maybe I approached this thread incorrectly, but my starting point is that from what I had read here and on many other forums is that no one had created a cogent argument that put to bed issues that I would have thought should not be debated.

The fact that there are still "golden ears" posts suggests that there is room for debate. Now where I think I have been clear is to say that I am not trying to give weight to their assurtions, but I have been trying to create a more compelling structure to refute their claims, or hold up a hand a say, though I do not beleive in your claim and though I think it is a flying spaghetti monster, I do not have irrefutable proof to show you.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: greynol on 03 April, 2012, 10:27:23 AM
I wouldn't necessarily assume that discussions remain open because there is still ground for debate that is not just faith-based.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Woodinville on 03 April, 2012, 06:32:41 PM
The fact that there are still "golden ears" posts suggests that there is room for debate.


Another suggestion would be to re-read the discussion at audioskeptic.blogspot.com (yes, that's mine) and especially concentrate on the last part. This should explain why we will always have golden ears and the like, I dare say, quite clearly.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Paulhoff on 03 April, 2012, 07:35:41 PM
I was thinking about writing a book, but I kind of like being retired, too...


An audio book for the Layman without all the WOO-WOO.

How it all really works.

That would be good.

Paul

     
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 04 April, 2012, 05:24:04 AM
@ 'Woodinville'
Actually I am completely aware of part 4 and is something I completely agree with. However that does not address the gap in my knowledge that means I do not feel I have that cogent argument I previously referred to.

Dare I say you have not sure gap given your years of experience. I have only recently become interested in this again ten years after I was looking at anything like this during university.

However given that there is no postive tests from ABX testing and given comparisons of waveforms so that other parts of the audio/processing system are likely to impact the sources to a greater extent than the delta in sources themselves, I am reasonably happy (though with still a nagging feeling) that no one can construct an argument that they can show that there is a difference.

That nagging feeling is that given the potential set of tools and procedures at our disposal, I would have hoped we can show more that what has at least been discussed in this thread.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Woodinville on 04 April, 2012, 07:03:08 AM
However given that there is no postive tests from ABX testing and given comparisons of waveforms so that other parts of the audio/processing system are likely to impact the sources to a greater extent than the delta in sources themselves, I am reasonably happy (though with still a nagging feeling) that no one can construct an argument that they can show that there is a difference.


Huh? Could you rephrase that?

Under good conditions, DBT's can resolve sounds down to within ->||<- of the actual noise level of the atmosphere at your ear drum.  Signal detection works a bit better for those, of course, although it is also a type of blind testing.

As to 'other parts' I have no idea what you're thinking of. An ABX test uses the same equipment for all tests, EXCEPT for the specific part under test. So there aren't going to be variations in the other parts of the system, unless they are caused by the part under test.

What does comparisons of waveforms have to do with anything?  SNR is mostly useless, after all. (Well, if you have 110dB SNR you're probably good, and under 6dB is bad, but between at least 6dB and 70-80dB you can easily make two signals one of which you can detect the error in, the other one which you can't.)

So, could you rephrase this in a a fashion a native english speaker can digest?
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Arnold B. Krueger on 04 April, 2012, 08:01:00 AM
However given that there is no postive tests from ABX testing and given comparisons of waveforms so that other parts of the audio/processing system are likely to impact the sources to a greater extent than the delta in sources themselves, I am reasonably happy (though with still a nagging feeling) that no one can construct an argument that they can show that there is a difference.


What is this "...given that there is no postive tests from ABX testing..." stuff all about?

There are tons of positive results from ABX tests.

The general rule for obtaining positive results from ABX tests is to select your tests from the realm of things that we know by other means to be audible. If you use ABX to double check a good recent textbook's statements about the thresholds of audibility for yourself, you might do a little better or a little worse, but that's the nature of small samples and particularly samples of 1. They vary a bit.

Let's look at the profile of your typical ABX test that the High End audio publications would and has complained about. In general, they don't provide any information about the technical performance of the equipment being compared, or if they do, a person who is well-informed about the human thresholds of hearing will probably dismiss the test on the grounds that it would require that the thresholds of hearing be orders of magnitude smaller then we know that they are.

In short, the ABX critics usually fault ABX just as sensibly as we might fault a champion runner for not being able to beat the current world's record by several orders of magnitude. You can't run the mile in 2 seconds? What sort of Olympic runner are you? Obviously sir, you are a fraud and completely undeserving of your honors. ;-)

Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Paulhoff on 04 April, 2012, 11:36:41 AM
In short, the ABX critics usually fault ABX just as sensibly as we might fault a champion runner for not being able to beat the current world's record by several orders of magnitude. You can't run the mile in 2 seconds? What sort of Olympic runner are you? Obviously sir, you are a fraud and completely undeserving of your honors. ;-)


Also, we know we can hear (something of your choice) but with ABX testing we don't, so it is the testing and not us that is wrong, therefore ABX testing fails.

Paul

 
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 05 April, 2012, 06:32:45 AM
Under good conditions, DBT's can resolve sounds down to within ->||<- of the actual noise level of the atmosphere at your ear drum.  Signal detection works a bit better for those, of course,

... So, could you rephrase this in a a fashion a native english speaker can digest?


Not sure about what you last line means as I am from the UK and many here seem to be from the States

But I am interested in your statement "... at your ear drum". I have clearly mis-understood what ABX is testing in that case, as I thought the comparison is being determined within the cortex, even if it is using stimuli from the ear drum and much processing between.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: 2Bdecided on 05 April, 2012, 06:47:34 AM
But I am interested in your statement "... at your ear drum". I have clearly mis-understood what ABX is testing in that case, as I thought the comparison is being determined within the cortex, even if it is using stimuli from the ear drum and much processing between.
He's telling you that, for certain tasks, that processing isn't doing much worse than a perfect microphone (at the ear drum) + perfect ADC + perfect computer could.

He's also trying to explain that, for many tasks, we know pretty well what's happening in the mechanical and transducer parts of the ear - and the results you get from asking people what they can and cannot hear match predictions of what those transducers (hair cells) in the ear pick up very well. So well that, for many tasks, that "much processing between" can just be considered as a near-optimal computer processing the signals from the hair cells.

In short, almost all the losses are in the mechanical and transducer part of the ear. "The rest" is acting like a very good computer, trying to extract something meaningful from those signals. It doesn't lose much. In fact, it's amazing how much it does pick out of the rotten signals it gets from the ear.


So you've got experiments from asking people what they hear, simulations of what's in the ear, experiments from probing real ears, known levels of atmospheric and in-ear noise, a century of scientific data, etc etc etc - all these agree. Then you've got audiophiles claiming that things which they shouldn't be able to hear (and that multiple failed ABX tests suggest they can't hear) are easily and obviously audible.

If you believe the latter camp, I've got some great magic sticks that I'd like to sell you. They just look like sticks, but they'll bring you health, wealth and happiness, not to mention marital bliss. A bargain at £100 a pair.

Cheers,
David.
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Arnold B. Krueger on 06 April, 2012, 11:32:49 AM
In short, the ABX critics usually fault ABX just as sensibly as we might fault a champion runner for not being able to beat the current world's record by several orders of magnitude. You can't run the mile in 2 seconds? What sort of Olympic runner are you? Obviously sir, you are a fraud and completely undeserving of your honors. ;-)


Also, we know we can hear (something of your choice) but with ABX testing we don't, so it is the testing and not us that is wrong, therefore ABX testing fails.

Paul

 



;-)

Right, which reminds me of the discussion of DBTs that was ongoing at the time we invented ABX for audio. People like Shanefield were using the word Epistemology, which is the study of how we know what we believe.

Do we believe certain things because that is what we think, or do we believe those things because of some formal, insightful methodology that we use to determine such things?

I sometimes call what the GEs do "Naive Perception". People who have any understanding of illusions, understand that perceiving is not necessarily believing. In the study of perception, the difference between an illusion and a reliable perception is just that, reliability. The illusory lake in the desert or wet spots on hot pavement disappear when we change our viewing point. The real lake about 2 miles from me right now does not disappear when I look at it from any reasonable viewing point. If I jump into it I get wet. None of this is rocket science to anybody but small children.

Quote from Dan Shanefield's CV (http://homepage.mac.com/shanefield/Resume1.html)

"
Created a "meme," in other words, a newly-created idea that continues to spread throughout the world on its own. This meme is the "equalized double-blind" listening comparison of audio components, which is now used worldwide. (See D. J. Shanefield, High Fidelity, March 1980, page 57. Also published in Boston Audio Society Speaker, Nov. 1974 and June 1975. Listed as the earliest double-blind audio articles: see Refs. 27 & 28 in S. Lipshitz et al., J. Audio Engrng. Soc., Vol. 29, July 1981.)

Introduced the graphic equalizer to the general public, with first article on this component in million-reader magazines (see for example cover story by D. J. Shanefield in Stereo Review, May 1976, referred to again in Stereo Review, May 1996, page 112).
"
Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: Arnold B. Krueger on 06 April, 2012, 11:44:36 AM
Under good conditions, DBT's can resolve sounds down to within ->||<- of the actual noise level of the atmosphere at your ear drum.  Signal detection works a bit better for those, of course,

... So, could you rephrase this in a a fashion a native english speaker can digest?


But I am interested in your statement "... at your ear drum". I have clearly mis-understood what ABX is testing in that case, as I thought the comparison is being determined within the cortex, even if it is using stimuli from the ear drum and much processing between.


What sets the ultimate threshold of hearing, even if we mistakenly presume that the ear has infinite sensitivity?

The ultimate threshold of hearing would be determined by the that is noise generated by the thermal agitation of the molecules in the atmosphere. The little buggers randomly bounce off our eardrums, right? They must be causing a steady rush of noise in our ears that masks other potentially audible sounds that are appreciably softer. That random noise due to the motion of the air molecules would limit our ability to hear softer sounds, even if our ears themselves had unlimited sensitivity, right?

Several relevant factoids.

One is that few if any of us have any perception of the noise created by the molecules atmosphere bouncing off of our ear drums, even if we are in a very, very quiet room.

Another is what JJ pointed out above, which is that we can do DBTs where people successfully reliably detect noises that are just a tad louder than the noise created by the  atmosphere molecules bouncing off of our ear drums.

Note that the noise level in even the quietest rooms we frequent are  20-40 dB louder than the noise created by the  atmosphere molecules bouncing off of our ear drums.

Title: ABX testing vs. unconscious perception/decision, enjoyment, and so on
Post by: icstm on 10 April, 2012, 06:19:28 AM
Hope everyone had a good Easter break.
Reading those last couple of posts I found very useful.
@David - forming the argument the way you did should surly put the other camp to bed... shame it does not.
Still it does mean there is money to be made from your magic sticks, I just hope you have a stomach that can handle selling them.