Originally Posted by cel4145
I'm looking at something different. It's the idea of whether or not critically evaluating headphones in ABX test is equivalent to the listening experience--outside of those biases. The end goal is a pleasurable listening experience; good SQ as determined by ABX testing, it is being assumed, is reflective of that pleasurable experience.
I disagree! While the "end goal" of someone taking an ABX test may be to achieve a pleasurable listening experience, that's not what an ABX test designed to achieve. All an ABX test is designed to achieve is whether or not the person taking the test can detect a difference between the items being tested. When we start looking at SQ in terms of "good", "bad" or "pleasurable experience" we enter the realm of individual perception and therefore by definition, individual bias. ABX testing is the best method we have of eliminating an individual's biases. To a certain extent ABX testing allows us to make a distinction between hearing and sound perception. Making a qualitative judgement appears on the face of it to be relatively simple, do we like something better than something else? In reality though it's a complex sequence of processes but the first of these processes is always; can we detect a difference? Unfortunately, the entire process of making a qualitative judgement can drastically affect whether or not the very first step is achieved accurately. ABX testing is designed as far as possible to eliminate the subsequent steps in the process of making a qualitative judgement and forces us to concentrate specifically on the first step. So I disagree with your statement, because ABX testing does not exist to determine good SQ, infact it could be said to exist specifically to avoid qualitative determinations!
Of course, all this raises various questions regarding the properties of sound, the human ears' ability to respond to those properties and the perception of sound. We have developed a branch of science specifically to deal with all this, psychoacoustics. The properties and behaviour of sound are very well understood, as is the physiology of the ear and how/what it is able to respond to, but while there have been great advances in psychoacoustics, there are still many more questions than there are answers when it comes to the perception of sound. While it would be nice to have a simple explanation of how we perceive sound, I don't agree with the original post, that scientists generally tend to believe that the perception of sound or the aesthetic experience of listening to music is in anyway trivial or that science has all the answers. In fact, if anything, the opposite is more true! We can make some very broad generalisations about sound and music perception and indeed many of these generalisations have been known about and consciously employed by composers for centuries but when we look in finer detail, it turns out that perception of sound is orders of magnitude more complex than the man-in-the-street (or even many music professionals) realise. Take the example of pitch detection, which on the face of it seems relatively simple but in psychoacoustics turns out to be a bit of a nightmare! All naturally occurring sounds contain a variety of frequencies, which we describe as a fundamental plus a series of harmonics. It is generally taught that the frequency of the fundamental defines the pitch of the note and indeed this is the basis upon which tuning and pitch detection software operates. We can prove this supposition by fabricating a single frequency (a sine wave) without any harmonics and the brain can indeed identify pitch. However, we can also take a complete note (fundamental + harmonic series), entirely remove the fundamental and still the brain can determine the pitch. So, we can take a note with no harmonics and determine pitch and we can take a note with no fundamental and determine pitch but we know there is no other component to pitch other than a fundamental + harmonics, so how the hell do we hear pitch?! It would seem that pitch is more of a human perception than of any specific quality of sound waves, even though pitch perception is directly related to frequency content. Psychoacoustics does have various theories but none of them fully account for pitch perception (see here for more details). I use this example of pitch perception to illustrate that even some apparently basic perceptions are not fully understood, let alone the issue of qualitative judgement of those perceptions. This raises the question of why perception even exists as something which is different to just hearing.
Science has discovered that the body's sensory organs produce many times more data than the brain could possibly process. To get round this problem, the brain essentially discards approximately 90% of this sensory data and then reconstructs or interpolates the remaining data to create an impression or perception of this data. Exactly how this process operates is not fully understood, although in general terms the brain appears to throw away large blocks of data and replace it with simple assumptions based on experience. This is the basics of how and why visual and aural illusions exist, by using the brain's assumption/experience data reduction technique to fool the perception. In some cases, knowing how the illusion works changes our knowledge/experience so we can perceive the illusion for what it is. In other cases, even knowing how an illusion works is not enough to stop us from experiencing the illusion, this suggests some sort of complex "weighting" between assumption and knowledge/experience, where one can overide the other and vice versa. What's also quite intriguing is that the concept of separate senses is in fact itself an illusion as it seems that the perception which results from the data reduction process is not separate at all but entirely interlinked. In other words, what we perceive as hearing is in fact a combination of all our senses plus a very significant dose of assumption and personal experience and, that this is true of all the senses. What we see is affected by what we hear, what we taste, what we assume and what we feel like. What we taste is affected by what we see, what we hear, what we assume and what we feel like and what we feel like is affected by what we hear, see, smell, taste, assume, etc. This makes a mockery of audiophiles who suggest there must be a fault with digital audio as a recording never sounds the same as the live performance. Understanding a few of the basics of audio perception suggests that even a theoretically absolutely perfect recording and playback chain will never provide more than a tiny fraction of the entire sensory data necessary, let alone the expectation and other assumption/experience components necessary to recreate an identical perception. If you can find it, watch the BBC Horizon episode - Is Seeing Believing.
We may one day understand perception better and discover ways to improve the ABX test so we can test more of the complexities of perception and of qualitative judgement but for the time being, ABX represents the best method we have of eliminating as much of the individual's assumption/experience errors (implicit in the perception process) as possible by asking the most basic question: Without knowing which is which, can we detect any sort difference between two items?
Edited by gregorio - 11/9/13 at 3:58am