A note to the reader: This is a lengthy and technically oriented article, with much discussion of setup, wiring and ABX testing conditions. I attempt to keep my articles accessible to the average audiophile, but admit that this will be too much for some. If you find yourself uninterested in the mechanics of setting up ABX systems I invite you to skip sections “It Takes An Audio Store” and “How I Did the Wiring”. However, gluttons for details and tortuous setup, enjoy!
ABX testing is taboo, a subject guaranteed to make some recoil with disgust, and others secretly wish they could experience. Not many in the audiophile community get to do ABX testing, and even fewer do so in an environment where multiple systems are established and controls used to ensure consistency of results. The purported outcome of such testing makes marvelous fodder for bickering among “authorities”; the “Subjectivists” don’t seem to care if anything is measured, and the “Objectivists” think measurements are the only thing that really matters. While that is a tad cynical, it gets to the heart of the issue, whether ears or instruments are to be trusted. I may as well wade right in to this backwater bayou filled with Crocs!
ABX, or double blind testing, is fraught with vicious attitudes and ad nauseam arguments about minutia. Sometimes people are ridiculed by those who despise their perspective. Threads on forums have to be closed or pulled, warnings issued, and some websites monitor for flare-ups on the topic.
Deep down we all want the proverbial Golden Ears. We all want infallibility in assessment of sound; otherwise, why waste our time on a demo of a piece of gear? Why have more than one recording of a performance? Why invite others over to discuss our shared experiences? Why read this article? I’ll tell you why. We want confirmation that our hearing is exquisite, that we can beat the machine and judge the sound more perfectly than the machine can play it back. We want to be perfect, and know that we hear the music as it really is! Well, for most of us maybe not all the time, but at least when we really need it, when purchasing gear!
But, would you be willing to actually test it? If given the opportunity, would you sit for a double blind test, and let others, or a machine detect how well you did? Would you admit if you couldn’t pass the test, if the ABX method did demonstrate that for you there was no difference between a type of component or system? Would you put your vaunted status as a wise, experienced listener on the line for one big roll of the dice, as it were?
Such were the variety of thoughts that raced through my mind when Frank Van Alstine of Audio By Van Alstine fairly challenged me to work with his “ABX Box”. The ABX Comparator is a fancy switchbox for multiple components such that one can compare sighted or blindly one or several components. It was designed by Dan Kuelchle, who worked with Frank to bring it to market.
How could I refuse Frank’s offer? I love building systems and comparing them, as well as having had a long running catalogue of ideas about ABX, but was never able to confirm them. Would doing so put my reviewing credibility on the line? Would my ego allow for a potential embarrassment, perhaps being shown that I cannot with certainty identify sound from level-matched gear? I knew what was at stake; if I was transparent with the process and did poorly, my nearly ten years of reviewing would be fairly worthless. I suspect the fear of the implications keeps many reviewers away from the process.
On the other hand, I respect manufacturers, designers, engineers and objective types, and saw an opportunity to see just how good my ears are, and how potentially fiendish ABX testing could be. I have casually followed the Fremmer/Randi fracas and thought to myself, “I wonder if I could win such a challenge?” If you know the challenge I’m referring to, the odds are you have wondered whether you could pass it yourself. We hard-core types wish we could go into such a situation and kick some ass, to select the correct cables and leave the cable skeptics speechless.
Aside from Frank’s gentle nudging, this article is not the result of some grand challenge. Nor is it about a Saturday spent drinking and running half-assed trials. It is about one man’s sensible and serene time spent with an ABX component designed to test personal limits of acuity, and sharing his thoughts about the nature of human auditory perception. It is about self-discovery as well as discovering what might really matter to the audiophile when it comes to gear.
In the end, I learned everything matters; well, almost everything, but not as much as you might think.
What does that mean?
What kind of a statement is that? It sounds like a contradiction, but it is actually a very succinct summary of what it is like to conduct ABX tests. Unpacking the comment, it means systems, when level-matched, have discernible differences, but may not have as much difference as we tend to think. One of the things I could not get over while using the ABX was how small the differences between speakers, DACs, or cables seemed! The recurring thought was, “If there is this small a gap in performance, then why am I spending so much money in the pursuit of better sound? That is a very uncomfortable feeling when participating in an ABX test.
Is it legitimate? Are the differences really so minor? They certainly were whenever I did comparisons using the Audio By Van Alstine ABX Comparator. Conversely, it seems the thin slicing, “sweating the small stuff”, seems to have a disproportionate influence upon our psyche. We hear a fresh interpretation of the music we love and it means the world to us! Something catches our attention, makes us adore it, motivating us to enthuse about it. During this review I moved through the emotions of dismay, disgust, joy, disappointment, excitement and satisfaction. There were many surprises in store for me. Let me introduce you to the device that caused such a range of emotions.
The ABX Box
The AVA ABX Comparator is essentially a switchbox that can assess multiple sources, preamps, amps, cables and speakers. From as few as two to as many as seven components/speakers can be compared in a blind or sighted listening. The ABX Comparator is built smartly, with well-snugged sets of RCA jacks and speaker binding posts; the construction and case is solid, but not extravagant. The backside is replete with pairs of inputs and outputs, cleanly marked in bold print, albeit in crowded fashion. From left to right, the connections are three sets of speaker posts, under which lie two “splitters” whereby one can input a line level signal and have it split to return to two different sources; subwoofer In and Out; A and B “SRC” (Source) Input; A and B Amp Output. A 15 amp IEC connection is used and the unit comes with a generic power cord.
The designations “A” and “B” constitute the uniqueness of each system, and when the AVA ABX Comparator is used for comparison, one selects between A and B, which are indicated on the front display panel by green (A) and blue (B) LEDs. A host of functions programmed into the Sony remote allow for the user to remotely set both A and B systems’ level, switch between one, two or three components in the A system or B system in sighted and blind listening, and preset both systems at matched listening level for quick switching between them “on the fly” when the music is playing. Further, one can darken the display either when in casual listening or test mode.
The ABX Comparator can only pass through a signal with or without attenuation. It cannot add gain, as it is not a preamp. The volume setting steps from 99 down to 10 represent an attenuation of about 1dB to 9.9dB in 89 steps. From volume setting 09 down to 00 the full range of the attenuation circuit is used, which is roughly 3 to 4 dB per step. Only in the event of a very low signal are the steps 0-9 used. The Owner’s Manual explains that in such a way the ABX Comparator can accommodate a comparison between an extremely “hot” source versus an extremely “quiet” source, or an extremely efficient speaker versus an extremely inefficient speaker.
The user should not worry if the readout represents numbers 90 or higher, as this is not indicative of driving the amp toward maximum output.
There are several other more obscure operations, and the informal Owner’s Manual with densely worded descriptions of functions covers all the bases, but I suspect it would put a quarter of the audiophile community reading it to sleep, while confusing another quarter of them. Had I not the experience of hooking up hundreds of systems I would find the discussion of wiring systems with the ABX Comparator daunting.
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