Working with the human ear: the proper evaluation of audio equipment incl. amplifiers

[Stephen PG]

The best investment the chronic audiophile can make is an annual subscription to The National Trust.

Any recommendations of NT places to visit in and around Brighton or the south coast in general?

The weathers improving, the car just sailed through another MOT (21 year old Honda Accord) and it's only an hours drive...

Oh, and bravo on the amp challenge!

[A.S.]

Any recommendations of NT places to visit in and around Brighton or the south coast in general?...

What a charming idea! I'll ask my wife - her opinion's a little different from mine. She likes the Capability Brown type landscaping: I like the interiors and to see how people lived, just as they left it. I'm particularly fond of rose gardens - and seen will be the season.

Have you been to Chartwell, Churchill's former home on the Surrey/Kent/Sussex border? It is rather moving to see his study, preserved as he left it and to allow your mind to consider what ifs ....

Are you far from Uppark - one of my favourites. Short video here.

[Don Jr]

Have you been to Chartwell, Churchill's former home on the Surrey/Kent/Sussex border? It is rather moving to see his study, preserved as he left it and to allow your mind to consider what ifs ....

That interests me as I was at the home of Franklin D. Roosevelt on the Hudson River in New York a few weeks back. He maintained not only an excellent working relationship with Churchill, but also a close friendship. His home was very interesting and left in tact. Because he was bound to a wheel chair, he had to pull himself to the second story of his home in a dumb waiter to get himself to bed. He also had a modified car that would allow him to brake and clutch with his hands.

I would love to visit Chartwell (UK in general) someday, maybe in a year or two.

[A.S.]

It never ceases to amaze me the extreme confidence non-engineers, non-scientists dedicated audiophiles place in organic senses. This is despite the evidence around us (and has been around us for hundreds or thousands of years) that our ability to compare X with Y is extremely poor unless a 'known' factor is introduced to aid the comparison.

The ruler was invented because of our inability to accurately determine distance
The camera was invented to capture and faithfully record optical events without relying on vague human memory
The scales were invented because of our inability to accurately judge mass by hand
The sound recorder was invented to record and replay sonic events then without relying on human memory
The ammeter and volt meter were invented to accurately measure electrical properties because of our innate inability to do so
The radiation meter to measure invisible, perhaps deadly radiation none of our senses can detect
The magnetic flux meter was invented to accurately measure magnetic field properties because of our innate inability to do so
The light meter was invented to accurately measure luminance properties because of our innate inability to do so
The clock was invented to accurately measure time because of our innate inability to do so
The barometer was invented to accurately measure pressure properties because of our inability to do so
The thermometer was invented to accurately measure temperature properties because of our inability to do so
The speedometer was invented to accurately measure velocity because of our inability to do so
The lens was invented to amplify the weak ability of our eyes to see small details
The sound level meter (or the VU meter) was invented to accurately measure 'loudness' because of our inability to do so
Currency was invented to represent an agreed unit of value

Examples of numerous instruments man has invented here. Indeed, even the laboratory was invented to eliminate or control variables that creep into measurements and tests.

... but the human ear is held-up by serious audiophiles (who generally are of middle age folk (like me) and hence will undoubtedly have significant natural degradation in their hearing depending on exposure and hereditary factors) as the most accurate - indeed only viable - sensor for the evaluation of sound. And those same middle aged folk, who select audio equipment for characteristics that (obviously) suit them and the condition of their ears, may inappropriately influence and excite others who may be younger, with better hearing and and entirely different evaluation process. Marketing people revel in that confusion!

Imagine a world where the instruments listed above ceased to exist or work. Complete chaos would result because of one humans inability to agree values with another, even down to the most basic bartering for food. It makes no sense at all, in fact, it is a denial of the human condition, to outright dismiss the technical measurement of audio equipment and to rely solely on our poor, unreliable and disease and age prone hearing. That's asking for trouble. I'd like to know how often the audiophile, the individual who places total confidence in his ears, has those very same non-instruments checked. The technical instruments I list above need to be routinely verified - but the ears?

Measuring instruments need routine calibration when they can usually be corrected for drift and returned to original accuracy. The ear of a man of 55 can never be as good as a man of 35; the 80 year old ear can never be as good as the 60 year old ear. The ear always degrades and unlike the technical measurement instrument, cannot be returned to 'as new' condition. Next week, sadly, our ears will be fractionally less good than this week, They are also, I'm advised, inoperable on.

Anyone who has or does experience any of these everyday events should recognise the potential effect on their hearing and be duly cautious about critiquing audio equipment:

• A head cold
• Influenza
• Numerous illnesses and diseases incl. mumps, glandular fever, tonsillitis, ENT infections ...
• Takes anti-depressants, heart pills, blood thinners etc.
• Has long shaggy hair that covers their ears (which greatly absorbs high frequencies and resets what other consider very bright as that listener's normal)
• Wears spectacles (changes sound diffraction around the head)
• Has suffered concussion
• Does not clean and de-wax their ears (I clean mine every day but that may be excessive)
• Is stressed
• Suffers dizziness or palpitations
• Is fatigued and suffers sleeping difficulties perhaps through pain
• Attends pop concerts without hearing protection
• Uses power tools without protection
• Lives in a noisy city (damages hearing acuity, desensitises hearing)
• Smokes (cigarette smoke hardens the ear drum making it leathery, less flexible and reduces HF sensitivity)
• Takes narcotics
• Consumes more than the maximum recommended dose of alcohol
• Has a job in a noisy environment
• Argues with his spouse, boss or children (raises blood pressure, creates anxiety, hyper-sensitises or dulls hearing depending upon fight or flight response)
• Has ear disease, diagnosed or not
• Has not had his hearing checked at least every two years exposing natural age-related degrading (or other factors)
• Has continuous background noise from street, neighbours, air conditioning, lift movement etc. (dulls sensitivity)
• Has to ask for speech to be repeated, cannot hear conversation in noisy restaurants etc.
• Is taking specialist 'herbal' extracts
• Is in continuous pain
• Is significantly over-weight
• Has recently travelled in an aircraft at height
• Has journeyed to/from home by noisy public transport
• Has journeyed in a car especially with a noisy exhaust or car radio playing loud
• Has a subwoofer and powerful amplifier as car audio system
• Prolonged use of headphones/in-ear speakers incl. TV talkback earphones
• Prolonged working in recording studio environment at high sound levels
• Professional musician performing in the near-field of their instrument
• Works with machinery which (unknowingly) generates sound at certain fixed tones (which kills hearing sensitivity at those frequencies)
• Work or leisure activity with firearms or explosives
• Has suffered from perforated eardrums
• Has had ear grommets fitted
• Has ever experienced ringing in the ears after exposure to loud sound
• Suffers from tinnitus
• Is into performance swimming
• Has to wear ear plugs at night to be able to sleep
• Extremely hot, cold, humid or dry atmosphere
• Has had ears syringed (be cautious: short term sensitivity boost, long term ...?)
• Repairs noisy machinery
• Works in the motor repair trade or tyre replacement trade (loud explosive noises, hard metallic high-energy noises)
• Is head over heels in love

and so on. A consultant audiologist would be able to add plenty more examples.

It is clear beyond doubt that the human ear, whilst a wonderful sense, cannot be separated from and be truly independent of the observer. It is therefore a personal gauge but not a reliable instrument. Its usefulness as a sound gauge can be greatly enhanced if as many variable are removed from tests involving the ear, and its predictable and recognised limitations (the list above) augmented by the use of technical instruments and procedures which are, unlike the ear, repeatable daily. Under those circumstances, it becomes a much more reliable and helpful sense.

Nobody wants to deprive the audiophile of the emotions associated with listening to music any more than depriving the Ferrari owner of admiring his car. We, in our western world need continuous consumption. But unless the emotional element of acquisition and ownership is recognised as a fact of human nature, marketers will pull those emotional strings to steer those would-be buyers towards their products. That's their job! The issue is, are those products actually the best sonic and Long Term Satisfaction solutions for the consumer? That, the marketeer is completely disinterested in: he's banked the money and skedaddled. To answer that, you have to set aside - or at least factor-in - the inescapable emotional components of consumption. And 'emotion' is just another word for 'psychological'.

I once bought a very attractive, powerful car when I was a bit miserable and susceptible on a wet Wednesday afternoon when I needed a thrill. The short term euphoria turned into a financial nightmare due to high running costs. It was entirely my own fault: the salesman merely sensed my state of mind and played to it. He was doing his job. The long term satisfaction was negative. Had I been blindfolded I would not have bought that Jaguar.

For me, the short term thrill of owning counts for nothing and the long term satisfaction of ownership counts for everything. I could buy any production car but out of choice my car is nine years old, long out of production. It is what it is: a large, reliable, boring, fuel efficient, comfortable vehicle with zero brand image: nobody is kidding anybody. It's a tool to get from A-B, just as an amplifier is merely a tool to magnify the microphone's signal. I have zero motivation to "trade-up", to "flip" the car for another. Nothing can be 'better', only different. I dread the day when I will have to part with her through lack of spare parts.

She's given me total Long Term Satisfaction. I feel the same about you owning Harbeth speakers.

[A.S.]

The audiophile has complete, unshakable confidence in his senses of hearing. But what about another sense - sight.

Let's take the discussion away from audio, into the realm of human colour sense. Let's imagine that using sight alone that you have to make a decision, and that decisionreally matters. Imagine you are the production manager for a huge textile company. Last month you produced 1,000,000 shirts in colour A; a very big contract. The customer was delighted. He's back for more. You've hunted all around the factory but there is not one piece of the last batch remaining to colour match against.

The small print of the customer's contract says that if the colour doesn't exactly match that of the last batch, you won't be paid even after you deliver. $5,000,000 rests on you making the right decision. Hundreds of jobs. It's not a matter of selecting the amplifier, cable or CD player for your home hi-fi system .... if you get this wrong, you're out on the street. You need to be sure that you've properly compared A with B.

Your customer is going to use the best colour measuring instrument money can buy. They're going to have it regularly calibrated. They're going to use that instrument to factually decide if A is exactly the same shade as B. And if it's not, they're going to produce that instrument, its calibration certificate and the old/new shirts in court. They're not going to use their human senses at all. They don't trust them, and they don't need to trust them.

Well, what are you going to do? Give the dye department the go ahead? Trust your human senses and 'gut feel'? If only you had the two shirts in your hand, side by side so you could make an instantaneous comparison between them ... a proper A-B.

Here is your colour match dilemma ... go here, should automatically start to play. Be sure to keep your mouse off the coloured box. Just observe. A-B test with 5 second interval. You see colour A for five seconds, then neutral grey for five seconds, then colour B for five seconds.

What do you think? Same or not?

(Please do not add comments to the slideshow).

[A.S.]

In the last post I showed you two orange colours for five seconds with a five second gap between them. Let's shorten our exposure to the three colours from five to three seconds. I have not changed any colours at all; just the display timer. Now what do you think? Are the two oranges exactly the same? There are no tricks. The comparison is exactly what I describe: orange v. orange. It is entirely possible (and to be expected) that your opinion will differ from other peoples.

Be sure to keep your mouse cursor off the coloured box. Nothing else has changed in any way: merely the timer.

Just observe here: A-B test with 3 second interval here.

I bet if you were that factory manager now, agonising over these colours with your job on the line, you'd wish you could compare side by side bypassing your highly unreliable human sensory memory. I know I would!

[delgesu]

i feel "x" is more {deleted}

best,
delgesu

[A.S.]

In the last post I showed you two orange colours with a three second interval ....

OK, let's move on.

Let's reduce the time interval between the two orange colours from three to two seconds. Once again, it should automatically play. Be sure to keep your mouse cursor off the coloured box and just observe. Nothing else has changed in any way: merely the timer.

Here is the version with A-B test with two second interval.

Now how do you feel about the similarity of orange A and B. Are they the same?

Tomorrow we'll reduce the interval to one second. And then to zero, just like an audio equipment A-B instantaneous change-over.

[Euler]

Let's reduce the time interval between the two orange colours from three to two seconds. [snip] Now how do you feel about the similarity of orange A and B. Are they the same?

Tomorrow we'll reduce the interval to one second. And then to zero, just like an audio equipment A-B instantaneous change-over.

OK, I'll take a shot. It seems to me that Orange X is {deleted}, but I sure wouldn't bet the success of my company on it. No one has to prove to me that the human senses can be pretty bad at making objective measurements, especially when the comparison isn't simultaneous or side-by-side.

Bruce

[P.C.]

Alan when you said " Tomorrow we'll reduce the interval to one second. And then to zero, just like an audio equipment A-B instantaneous change-over."
does that mean your listening to just a single music note ( the equivalent to just a single color as in the visual test shown) when you do the audio A-B test?. If not but rather the music is constantly changing how can one compare even after just a second?. Wouldn't that be like using a Andreas Gursky large scale photo as a comparison rather than a single color?http://www.camera.co.uk/wp-content/u...eas-Gursky.jpg

The only way one could see the real differences between two subtly different copies of the Gursky would be to spend considerable time to study and scrutinize many details and passages within the picture. Flashing between them quickly would never reveal any difference even thought they are there.

Is this the same with ever changing complex music and its reproduction? Would real audible differences between amplifiers etc only reveal themselves after similar prolonged study of the whole reproduced experience?

[A.S.]

The first continue with our orange v. orange observational experiment: Now I've reduced the gap to one second.

Nothing else has change. What do you think now? (Thanks to commentators for taking the trouble but their precise conclusions erased to avoid bias).

Alan when you said " Tomorrow we'll reduce the interval to one second. And then to zero, just like an audio equipment A-B instantaneous change-over."
does that mean your listening to just a single music note (the equivalent to just a single color as in the visual test shown) when you do the audio A-B test?. If not but rather the music is constantly changing how can one compare even after just a second?...

The short answer is that when we apply our brain/senses to the world we are sampling the world as a dog sniffs scent. We have to focus our momentary attention on the aspect of the environment we want to sample. There has to be a minimum exposure or sampling time for the electro-chemical process in our sensor/brain reaches a conclusion. The scent, sound, temperature, feel, taste, image has to exist for a minimum time to register (that is, be interpreted) but needlessly extending the sampling period may or may not necessarily reveal more of the environment. It may in fact dull our experience through over exposure*.

As with wine: that first swallow yields much information about the grape, but after ten glugs taste and smell has dulled: emotional response and the presence of the alcohol in the blood will influence the sensory experience. That's what we're trying to avoid when designing audio hardware. A narcotic-induced state of persistent high-sensitivity with our senses buzzing is exhausting and and of no evolutionary (survival) advantage. So no, not switching on notes because they are too short to 'register', ditto test tones or even random noise. I use music as the stimuli to trigger an analytical comparison in my brain. The length of time dwelling on A or B varies depending on the music, what I'm sniffing-for in the music and whether I can detect it or not.

I've been doing this for so long, it seems totally logical - indeed, the only way to work. And this methodology has produced original Compact, HL5, P3/ES, DMP1, DPM1S, S8, SHL5, Monitor 30, NRG2, Monitor 40, Monitor 40.1, C7ES3, P3ESR .... so it works for me! The trick is that A-B comparisons heightens the contrast, heighten the difference, between A and B. If you are designing a new generation of loudspeaker or even comparing with a well respected competitive model hopeful of your own performance advantage and sales, you need to be cruel and objective, and that means instantaneous switch-over. Or so it does to me. This entire process which seems to have caused immense suspicion, confusion and hostility (>26,000 hits in a just two weeks on the internet) needs explanation and is being covered here.


*Have you noticed that if you stroke another's skin, the first contact generates a strong even thrilling experience of temperature and texture. But if you leave your hand motionless in place, after not many seconds you register neither. You have to move your hand again to re-sample the skin and provide renewed electrical input to your brain: the first impression has completely faded out.

[A.S.]

If you've followed me along this journey, you may or may not have detected a difference in the orange colour A and B. Perhaps you started out thinking they were different and now you think that they are the same. Or vice versa. The point I hope to have imparted is that for human senses to rationally appraise the world around us, we really need to be presented with simple, immediate comparatives. They we're pretty good at making reasonable choices when ...

• Asked what 100g feels like, we'd have great difficulty: given two apples and asked which was heavier we'd probably get it right 99/100 unless the weight difference is small
• Asked if one room is 3 degrees warmer than another we'd struggle to say, 1, 2, 3 or 5 degrees. Asked if the water from the hot tap is hotter than the cold tap we'd probably get it right 99/100 unless the temperature difference is very small.
• Asked if sound C is louder than sound D we'd probably get it right 99/100 if C and D are of the same pitch and are played in rapid succession after each other unless the difference is very small

Essential point .... our senses are not designed to measure absolute anything. The are honed by evolution to make valid comparative measurements with a short time gap between, and nothing more than that. Those sort of yes/no, same/different, danger/no danger comparisons are what evolution has optimised us for, because in evolutionary terms, the vital decisions, the ones that determine in the next ten seconds if we are individually at an evolutionary dead-end are those pass/fail, go/no-go decisions.

The detection of very small differences between sound, colour and temperature are in evolutionary terms, irrelevant at this stage of man's evolution and development. That's not to say that in a million years a human may be able to detect 0.1 degrees temperature change or the difference in loudness of 0.1dB: but that's certainly not where we are now along the evolutionary path. And I can't see any evolutionary advantage for those skill being honed - can you?

So what happens when we completely remove the time gap and flip directly from orange A to B? Instantaneous A-B comparison without gap here. The exact same images and colours in the first step.

Now what do you think? Surprised? Is orange A identical to orange B? Has your opinion changed as the gap has shortened? Did you comment when there was a five second gap that A and B were "EXACTLY the same"?!

[W. B.]

I am a bit confused now. As English is not my first language and school days are a long time ago, I am not sure that I understood it right.

I see now definitely that the two colours are different somehow, maybe not the colours, it could be also the brightness of the stimuli, too. If I hide the letters I am able to see a change frequently and without any doubt.

On the other side this example used here seem to me less surprising and a bit more complicated. As especially the visual sense of the human being follow his own rules as I remember my days at school. The neurons stimulated by visual stimuli are reacting in a special way at changes. The difference between two different stimuli will also appear bigger that it might be. If there is no change the perception adapts quickly.

The eyes are always moving. Only this makes them able too see. The little gap between the two stimuli in this experiment was provocating some inverted after glowing impressions at the neurons connected to the retina. This was disturbing the comparison of the two colours and made it impossible to detect a difference or none.

The relation between the visual sense an the more complex visual perception including the evaluating of visual information with all the relations to experience and emotions still seems to me quite vague.
Regards
W. B.

[A.S.]

It's not necessary to think too deeply about this visual experiment. The sole purpose is to show how the time gap between two sensory inputs to our brain can influence our perception. This is highly relevant to judging sound where the very same mechanism (obviously) exists. If our human exposure to sonic experience B is much separated from sonic experience A - by how much? seconds? minutes? days? years? - is it not likely that the validity of our opinion must be questioned? If the sonic gap, as I've shown here with the orange images is made as short as possible between the experiences does that give us a more reliable opinion? In other words, when images - and sounds - are abruptly compared against each other, we humans are in a better position to detect the objective truth about their innate nature.

What we must accept is that, in this experiment, the 'truth' is revealed only in the last step, Step 5 where there is an instantaneous switch from A to B. All other steps yield an ambiguous opinion about A v. B. But surely nobody would refute what they experience in the Step 5 - the same truth that an objective technical instrument would detect, time gap or no time gap. Last century, today, one hundred years from now.

To reiterate: Human judgement of A and B is inexorably bound-up with the exposure timing of A and B. That inter-sample time gap has no relevance to an measurement instrument. Had we used a colour measuring device back at step one, the truth about A and B would have been apparent even though, to the eye there may or may not have been a visible difference. So, should the factory manager have proceeded with the production of dye for order B and put $5,000,000 and his family on the line?

For clarity, here are the steps again.

Step 1: 5 seconds between A and B
Step 2: 3 seconds between A and B
Step 3: 2 seconds between A and B
Step 4: 1 second between A and B
Step 5: Instantaneous comparison between A and B

I'd like to show you another example tomorrow.

[EricW]

What we must accept is that, in this experiment, the 'truth' is revealed only in the last step, Step 5 where there is an instantaneous switch from A to B. All other steps yield an ambiguous opinion about A v. B. But surely nobody would refute what they experience in the Step 5 - the same truth that an objective technical instrument would detect, time gap or no time gap.

What I found interesting is that even a one second time gap gave me no greater certainty than a five second gap. Initially this seemed counter-intuitive: once I had seen the difference clearly on the instantaneous switch, I thought there'd be a higher degree of certainty with the one second gap than the five second gap. Not so. I can only guess that the gap created a new intervening perceptual stimulus, and that seemed to be enough to wipe out the brain's ability to distinguish between A and B - even when I knew what the difference was.

[Kumar Kane]

On the subject of all amplifiers sounding the same once level matching is done, would this be true regardless of the nature of the amp? Would there be no heard difference between an appropriate power rating tube amp when compared to a solid state one?

{Moderator's comment: No idea. Tube amps introduce well known electrical characteristics and these should be detectable by ear. If they are not, it just confirms how poor the ear's resolution actually is.}

[A.S.]

What I found interesting is that even a one second time gap gave me no greater certainty than a five second gap. Initially this seemed counter-intuitive: once I had seen the difference clearly on the instantaneous switch, I thought there'd be a higher degree of certainty with the one second gap than the five second gap. Not so. ...

So, even when you knew from Step 5 (the instantaneous comparison) the absolute truth about A and B, when events A and B are again separated by even a one or two second time gap, the difference (if any) is indistinguishable. This is why people persist throughout their lives in repeating the same mistakes - and are ever surprised that they are caught out! My wife has certain favourite clothing colours and in her wardrobe will spend time (seems like hours to me!) selecting this blouse with that skirt so that they colour match to her satisfaction. But I'd be a rich man (OK, a wild exaggeration) if I received $10 for the each occasion she'd returned from the shops, having relied on her colour memory, with a handbag or accessory which upon final A-B comparison was a significant shade away from her wardrobe favourites .... and return the item to the shop. Very normal consumer behaviour: over-confidence in sensory memory.

The audiophile believes that he can play an entire track from start to finish - perhaps ten or twenty minutes exposure - stop, disassemble the system, reassemble (minutes pass) and then start the same track at the very beginning and play it through and then reach a rock-solid conclusion about the two systems. It's nonsense of course. To start with, western music usually has a structure: a beginning, a middle and an end. During that journey there is usually a change in pace, pitch and intensity. The listen-to-the-whole-track concept miserably fails as an objective comparison because that emotional journey and conclusion of the first song is then compared with the opening statement of the song played again from the beginning. That is highly confusing to our brain: to be led to an emotional climax after which our brain is awash with endorphins and then, after a pause, to start-out again. That may be a perfectly valid experience in itself, but is it objective enough? I don't think so.

In the A-B orange comparison (above posts) we were presented with solid blocks of colour. Had the slide show software permitted, I could have reduced the exposure to orange A or B to a tiny fraction of a second, and providing that A and B were abutted without a gap, the truth of their colour match or not would still have been evident to our eyes. Those solid blocks of colour required little processing power in our brain: every part of the image from our retina to our brain (excepting the area occupied by the letters A and B, a small part of the overall image) would have contained the same, reinforcing electrical stimuli. I would anticipate that someone with significant optical degeneration would be equally able to detect the colour match. That crude block-colour test is analogous to hearing two adjacent sound tones: our brain can fully concentrate on interpreting a narrow range of stimuli. But as we've seen, even then when our full processing power is applied, separate the experiences by a few seconds, and our ability to resolve differences becomes shockingly poor.

What about an optical analogy for music - lots of detail and microtonality. Thanks to P.C. (post #70) who provided a picture of supermarket shelves busy with different shapes, sizes and coloured goods. Compared with our solid colour block images, that's much more like music as he hints: a busy scene for our human (optical) sensory sampling system . There's a lot of visual data to take in and process.

To give ourselves a fighting change, images X and Y will be displayed for 5 seconds with a 5 second gap. Are they the same? Are you able to absorb the entire scene and hold it in your mind and then make a valid comparison? If you can't hold the entirety of the scene in short term memory you'll have to guess.

Supermarket shelves - 5 seconds exposure, 5 seconds gap

If you are an audiophile who claims to have an aural memory that spans minutes, hours or days, you should have no difficulty with concluding if X and Y are the same or not. A $5,000,000 wager on this one perhaps?

[A.S.]

Now we'll reduce the exposure from 5 seconds to 3. The images have not been altered at all since Part 6.

Are these two pictures, representing the complexity of musical phrases, identical or not?

Supermarket shelves - 3 second exposure, 3 second gap

This should be easy shouldn't it ....

[EricW]

This should be easy shouldn't it ....

It doesn't begin to be anything approaching easy.

I have a question, however. Is the discrimination of relative levels of quality perhaps different different from the ability to distinguish (or more accurately, not distinguish) physical properties such as colour by reference to memory or some internal standard?

To take the example of your wife and the blouse. I can see how your wife might find a blouse in the store and think (for example) that it's the exact shade of blue she needs to match some other article of clothing she owns, only to find it's not so when she makes it home.

However, if the comparison is not of a specific physical property (such as exact colour), but rather the overall quality level of the blouse (natural fabric versus synthetic, fine versus coarse, machine made versus hand-stitched, etc.), I wonder if the internal comparison would have been more accurate? Is it possible that, although we may not be able to discriminate accurately in terms of objective measurement (without instruments), we may be able to gauge quality relatively accurately even without direct and immediate comparison?

[STHLS5]

As a lay person, I went through a long journey to finally settle with my current cables, Cd players , amplifiers and Harbeth for my musical enjoyment. But if I were to start my journey with a proper scientific mind and conducted a ABX test on each equipment then I would be still listening to some mediocre speakers and equipments because on many occasions I just failed under the DBT ABX tests.

Under the scientifically recognized ABX DBT there is no way I could properly do a valid comparisons with Harbeth and a X brand speakers. Scientifically, it is required that I do an instantaneous switchover to compare between two sets of speakers. But how is that possible? Firstly, how are we going to place two sets of speakers in an identical position in succession and instantaneously? Physically that is an impossibility unless I have some magical powers that I could replace the speakers in the exact position with a flick of the fingers. Can then someone argue that I am disillusined for saying Harbeth is one of the finest speakers that money can buy? Am I wrong to say they are natural and detailed speakers just because I could not do a scientifically accepted ABX test to prove that Harbeth was the better speaker?

Remember under the ABX rules everything must be equal before the test starts.

There are many things that I couldn’t tell under DBT. The small radiation dosage that I receive when taking X rays nor the ultraviolet light that I am exposed momentarily on daily basis. But that doesn’t mean they do not have an effect on me. It may not be obvious immediately or under ABX but on prolonged exposure your body and mind will show some symptoms.

Take another example, as liquor is taxed 300% in my country, you will come across pubs selling adulterated alcohols. Under DBT, I am unable to distinguish them until the next morning when I wake up with a headache.

Coming back to audio, unlike the above examples, I do not exhibit any after-effect by listening to inferior amplifiers or Cd Players but that doesn’t mean that I do not have emotional effect. At least in last one month or so with my Sony and Marantz I am emotionally attached to one in preference to the other. Why? Price? It cannot be so because there were many occasions that the cheaper ones triumphed over the more expensive equipments. Emotional attachment? Not me, I don’t let heart to rule over head.

And for Harbeth, I honestly doubt if we really need to bother with the small difference between well made amplifiers and up to Harbeth specification.

ST