A stereo system, a set of active and passive components, passes musical and nonmusical information from a recording to a transducer which renders the information perceivable to the human ear.

The above is a denotative description of what a stereo system does. The purpose of a stereo system concerns its connotative descriptions, i.e., its effects and affects. What a stereo system can do may be divided into the following categories: (1) Accuracy of signal transmission (effect). (2) Accuracy of representation of instruments (effect). (3) Idiosyncratic sonic preference(s) (effect). (4) Idiosyncratic non-sonic preference(s) (affect). (5) Healing and/or therapeutic benefits (affect)

Consider a recording. There is the composer's intention, the artist's intention, the producer's intention and the listener's intention. A recording reflects the goals of the producer which may agree or disagree with those of the composer and artist. Most audio professionals believe that a stereo system should maintain the integrity of the recording, in order to communicate the intention of those involved in the recording process. This goal can be realized when the recording is presented to the listener without any errors. The ultimate realization of this goal is perfection, namely, a complete absence of coloration. Such a state can never be achieved. Yet, empirically, one may create the conditions in which coloration is barely audible and as a result, minimally intrusive.

There is another reason for the popularity of accuracy, namely, the belief that fidelity to the source should be an end in itself, an intrinsic tenet of audio design and the epitome of sound quality.

The 'true' sound of instruments, i.e., their pitch, timbre and harmonics, is never heard on a stereo system. The larger the ensemble, the more difficult it is to achieve an accurate representation of the sound of instruments. The 'real thing' is a reference and may motivate many audio hobbyists to configure, adjust and tweak components to try to attain a 'sound' which creates some semblance of realism, subject to constraints of budget and expertise. The consequence of such an effort may be the introduction of coloration to compensate for recording deficiencies. Even if coloration is not explicitly or implicitly introduced, all stereo systems are imperfect. Those with obvious flaws, e.g., a consistent sonic signature, may reflect the personal taste of their owners. Certain musical aspects and sonic artifacts of a recording may be emphasized or deemphasized, consistent with personal taste. This view of a stereo system is antithetical to that of accuracy.

The power of music to assist the healing process and facilitate healthy physiological and psychological states is the basis of music therapy. Music often accompanies other activities, appealing to the head or the heart. Music can stimulate, help to reduce tension and blood pressure and create a soporific state. The effectiveness of a stereo system as a mood enhancer may depend upon sonic considerations as well as the music itself.

Conspicuous consumption may contribute to self esteem, and/or satisfy other psychological needs. Along with other (expensive) consumer durables, a stereo system may serve to influence the attitudes of other people. For some, the utility of a stereo system may not reside within its inherent sonic qualities but rather depend upon its affects upon the owner and others who come into contact with it.

I have briefly described capabilities of stereo systems of a sonic and nonsonic nature and for ease of analysis placed them in five groups. The purpose(s) of a stereo system reflect the varieties of listener intentions. Selecting among the competing purposes is purely subjective.

The relationship of how well a stereo system satisfies one's objectives and some measure of its (sound) quality has yet to be examined. However, anecdotal studies published in Stereophile several years ago would lead one to expect that (sound) quality, however it is measured, is not a good predictor of personal satisfaction.

Significance and Conclusion

It has been shown that a stereo system has many capabilities and functions. They are embodied in the following principles: 1) High Fidelity -- minimization of coloration 2) Musicality -- creation of the 'sound' of instruments 3) (Self) Gratification -- satisfaction of one's preferences.

The path to sonic excellence varies with each principle selected. Each of the above principles connotes a criterion which can be used to evaluate sound quality, namely neutrality, realism of pitch, timbre and personal taste, respectively.

A stereo system rated favorably according to one criterion might be deemed mediocre with respect to another. For example, consider two stereo systems, A & B. Suppose A is judged to be nearly neutral while B is euphonically colored. A might be judged inferior to B based upon the criterion of personal taste, whereas A might be judged superior to B if neutrality were the basis for comparison.

The potential of stereo systems to create the effects of neutrality, musicality and pleasing sonic palettes may generate divergent assessments of sound quality which cannot be definitively resolved.

Is there any way to extricate oneself from competing assessments of sound quality by devising an absolute standard?

Attempts to establish the 'ultimate' criterion for determining sound quality and, by implication, the purpose of a stereo system are philosophical, theoretical and subjective in nature. Such efforts are based upon opinion and judgment of professionals and cannot be validated.

The principle of high fidelity is often cited as the purpose of a stereo system and as the benchmark for assessing sound quality. Most audio professionals who support the aforementioned principle would also espouse the idea that sound quality is inversely proportional to perceived coloration. While systems differ with respect to levels of audible coloration, different is not a synonym for better. I believe the essential reason for asserting the inferiority of colored stereo systems is the idea that variety is superior to sameness. A persistent observable sonic 'flavor' may be boring and mask subtle and/or not-so-subtle details of a recording. The objections to coloration are not based upon logic or knowledge, rather on the basis of personal preference.

The high fidelity principle does not follow from an axiom or postulate. Therefore, it may not be a necessary condition of sonic excellence.

One can assert a premise, such as 'when listening to a recording, the intent of the conductor and the engineer should be preserved', or 'music should be appreciated (enjoyed), regardless of its sonic presentation'. One may then deduce one of the three aforementioned principles which, empirically, is likely to be consistent with each premise.

Premises like the two indicated above have no intrinsic merit which can exclude other premises. Rather they may represent agreement between audio professionals and/or hobbyists. They are not right or wrong, correct or incorrect. They may be accepted and/or rejected and may be argued cogently with varying consequences for those adopting one position or another. They are a matter of opinion, as are the principles which can be reasoned from them.

I will now present a simple logical analysis to show that the high fidelity principle, i.e., the neutrality criterion, does not support the position that one stereo system is inferior to another. If required, I could repeat this approach for any other principle selected and demonstrate that no criterion supports a position that stereo systems are inferior or superior to each other.

I assert that the statement 'coloration connotes inferior sound quality' is illogical. Let's see why this is so.

Assume the premise:

(1) If neutrality then excellence of sound quality

This means that if a stereo system is 'neutral' it has excellent sound quality. In this case, neutrality is a sufficient condition for excellent sound quality.

Statement (1), above is NOT equivalent to:

(2) If excellence of sound quality then neutrality

Statement (1), above is NOT equivalent to:

(3) If non neutrality then not excellence of sound

Statement (1) above is equivalent to:

(4) If not excellence of sound then not neutrality

If statement (2) were equivalent to statement (1), all instances of sonic excellence would be accompanied by neutrality. Statement (3) being equivalent to statement (2) would insure that non neutrality (coloration) would not be a characteristic of sonic excellence. One could then conclude that neutrality was superior to coloration (non neutrality).

Since (2) and (3), above are not equivalent to statement (1) above, neutrality is not a necessary condition of good sound. A stereo system may have excellent sound without being considered neutral.

Statements (1) and (4) taken together imply that some excellent sounding stereo systems are neutral and stereo systems which do not produce excellent sound quality cannot be neutral.

The consequence of assuming the 'truth' of statement (1) above is that stereo systems which sound 'good' may either be neutral or colored. There is insufficient information to ascertain what condition is necessary to attain sonic excellence. There may be attributes of a stereo system other than neutrality which are associated with a stereo system having excellent sound.

While most would accept the notion that enjoyment of one's stereo system is the top priority, there seems to be a dichotomy between personal preference and (sound) quality. The listener is taken out of the equation. 'Quality is in the ear of the beholder' is replaced by quality determined by an objective standard supported by agreement among experts.

Any criterion used to assess the merits of stereo systems is valid as long as it 'measures' some aspect of its performance. Currently, the conventional wisdom offers accuracy as the paragon of quality.

The statements 'less coloration is better than more coloration' and 'more information is better than less information' are not factual. Their content is not knowable. These statements are neither true nor false. Therefore they are opinions. It is a fact that some stereo systems are less colored than others. The application of relative or so-called absolute superiority after the fact is a value judgment, an opinion, based upon experience and consensus, not of necessity.

Evaluation of stereo systems based upon the neutrality criterion, deducible from the aforementioned premises (statements), is as valid as the result of evaluation using a criterion deducible from a premise such as 'stereo systems I like are better than those I don't like', namely, the self gratification criterion. Results can be disputed in either case.

The criticism that evaluations, which are unreliable and inconsistent, invalidate a criterion, are only indictments of the fragility of perception and differences in tastes, not the inadmissibility of the criterion itself. Objective criteria are also applied in a subjective manner, namely, by audition. There is a potential for inconsistency when such matters as the detection of subtle inaccuracies are concerned.

The criticisms of how a criterion is implemented do not in principle nullify the justification of the criterion.

Just as stereo systems are essentially erroneous devices, the methods used to evaluate them are also error prone. Stereo systems are different. Whether one is better than another cannot be proven definitively.