Engineering For Audio Sound Quality:
Having written several thousand product reviews, you might expect that I would have come up with the answer to the question:
Have you developed a reliable framework of technical parameters and measurements which determine sound quality? The answer is no!
Iíve published a number of articles which I hope have shed some light on the subject, but in the main I've learned not to pre-judge any technology, whether old or new, simple or complex. In my experience how a particular designer uses a technology he or she has chosen is more important in determining the quality of results than the technology itself.
First and foremost, the designer must appreciate the many dimensions of reproduced sound quality and use this as the foundation for the design of audio products. In particular, the innate sense of rhythm common to most primates should be a guiding force, since this is what makes music interesting and holds the listenerís attention. High fidelity is an imperfect concept but when delivered with sufficient rhythm, much may be forgiven. But the ability of audio products to convey rhythm in sound cannot be defined by measurement. Time and again I find that when the designer is conversant in the language of rhythm, the resulting products are musically interesting and entertaining.
See Pace, Rhythm, & Dynamics, Martin Colloms, Stereophile, first published November, 1992, now available on download at HIFICRITIC.COM
I have heard many technically accurate and beautiful sounding audio components and systems which lack sufficient rhythmic expression. While initially impressive, they do not hold your attention for long periods. These are the systems where you keep trying new tracks to see how good it sounds, rather than play that disc through and enjoy the musical performance.
Classic engineering theory remains valuable for design; it helps produce something that's reliable, effective, conforms to basic test and safety standards, with good compatibility to other audio products. But classically taught engineering excellence will not guarantee excellent sound quality.
See the excerpt below from Stereophile article Working in the Front Line.
Reviews have rated both solid state and valve/tube amplifiers as close to excellent. But both these technologies have provided equally indifferent performances in a number of product designs.
Some thermionic amplifiers can sound quite solid state especially if using relatively high loop negative feedback, while low or 'zero' feedback solid state models can sound sweet and valve-like in the expected sense. Amazingly, and for some critics paradoxically, the best of the tube SE, single ended, zero feedback designs have exhibited remarkable subjective 'speed' and vivacity, combining authentic tonality with natural rhythm and dynamic expression. Standard technical assessments cannot predict such variations and judged by conventional test criteria perform relatively poorly.