good topic, invite here to read this interesting piece written some time ago. it is called:
Are you on the road to audio hell?
The proposed system: comparison by contrast.
When audiotioning only two playback systes using the usual method (comparison by reference) we will have at least 50% chance of choosing the one which is the more accurate. However, evaluations of single components willy-nilly test the entire playback chain; therefore efforts to choose the more accurate component are compounded by the likelihood that we will be equally uncertain as to the accuracy of each of the system’s associated components if for no other reason than that they were chosen by a method which only guarantees prejudice. How can we have any confidence that having chosen one component by such a method that its presence in the system won’t mislead us when evaluating other components in the playback chain, present or future.
The way to sort out which system or component is more accurate is to invert the test. Instead of comparing a handful of recordings -presumed to be definitive- on two different systems to determine which one coincides with our present feeling about the way that music ought to sound, play a larger number of recordings of vastly different styles and recording technique on two different systems to hear which system reveals more differences between the recordings. This is a procedure which anyone with ears can make use of, but requires letting go of some of our favoured practices and prejudices.
In more detail, it would go something like this: Line up about two dozen or so recordings of different kind of music – pop vocal, orchestral, jazz, chamber music, folk, rock, opera, piano – music you like, but recordings of which you are unfamiliar. ( It is very important to avoid your favourite ‘test’ recordings presuming that they will tell you what you need to know about some performance parameter or another, because doing so will likely only serve to confirm or deny an expectation based on prior ‘performances’you have heard on other systems or components. More later ) First with one system and then the other, play through complete numbers from all these in one sitting. ( The other systems may be entirely different or have only one variable such as cables, amplifier or speakers.)
The more accurate system is the one which reproduces more differences – more contrast between the various program sources.
To suggest a simplified example, imgagine a 1949’s wind-up phonograph playing recordings of Al Jolson singing ‘Swanee’ and the Philadelphia Orchestra playing Beethoven. The playback from these recordings will be more alike than LP versions of these very recordings played back through a reasonably good modern audio system. Correct? What we are after is a playback system which maximises those differences. Some orchestral recordings for example, will present stages beyond the confines of the speaker borders, others tend to to gather between the speakers, some will seem to articulate instruments in space; others present them in a mass as if perceived from a balcony; some will present the winds recessed deep into the orchestra; others up front; some will indulge the bass drum with tremendous power; others barely distinguish between the character of tympany and bass drum. It is absolutely no consequence that these differences may have resulted from performing style or recording methodology and manufacture, or that they may have completely misrepresented the actual live event. Therefore when comparing speaker systems, it would be a mistake to assume that one which always presents a gigantic stage well beyond the confines of the speakers, for example, is more accurate. You might like –or even prefer- what that system does to staging, but the other speaker, because it is realising differences between recordings, is very likely more accurate; and in respect of the other variables from recording to recording, will turn out to be more revealing of the performance.
Some pop vocal recordings present us with resonant voices, others dry; some as part of the instrument texture, others envelope us leaving the accompanying instruments and vocals well in the background; some are nasal, some gravely, some metallic; others warm. The old method –Comparison by Reference- would have us respond positively to that playback system, which together with the associated ‘reference’ recording, achieves a pre-conceived notion of how vocal is presented and how it sounds in relation to the instruments in regard to such parameters as relative size, shape, level, weight, definition, etc. Over time we find ourselves preferring a particular presentation of pop vocal (or orchestral balance, or rock thwack, or jazz intimacy, or piano percussiveness- you name it) and infer a correctness when approximated by certain recordings. We then compound our mistake by raising these recordings to reference status (pace prof. Johnson), and seek this ‘correct’ presentation from every system we later evaluate; and if it isn’t there, we are likely to dismiss that system as incorrect. The problem is that since neither recording nor playback system was accurate to begin with, the expectation that later systems should comply is dangerous. In fact, if their presentations are consistently similar, then they must be inaccurate by definition simply because either by default or intention no two recordings are exactly similar, and while there are other important criteria which any satisfactory audio component or system must satisfy –absence of fatigue being one of the most essential- very little is not subsumed by the new method of comparison offered here.
Peter Quortrup AUDIOPHILE UK edition February 1994
