Ears versus Brains…

By Bryan Geyer

Audiophiles often say “trust your ears”, but rigorously controlled trials conclude that what you think you heard is overwhelmingly predetermined by what you saw before or during your listening session. Clearly, vision overrides hearing; refer “Sight Over Sound in the Judgment of Music Performance”, at http://www.pnas.org/content/110/36/14580.

When components are compared under conditions that are not restricted to double blind control, expectation bias* and confirmation bias** will swamp aural perception. What you’re predisposed to conclude (by previously viewing the evidence) is what your ears will reaffirm. Refer https://www.audioholics.com/room-acoustics/mind-over-music. Also https://www.audioholics.com/editorials/placebo-effect.

The ability to accurately assess the performance of a specific piece of audio equipment is heavily dependent on the skill of the examiner. At a minimum, some recent grounding in basic (repeat: basic) electrical engineering is essential, as well as some practical experience in the application of analog audio circuit design. When these qualifications are satisfied and there’s free access to the relevant product specifications, a competent technician should be able to…

     …accurately assess the component’s probable performance.

     …identify any implicit limitations, and judge their impact.

     …project potential means for improved performance, and rate the relevance.

The common recourse for those who are not qualified to conduct an effective technical analysis is generally a listening trial. Unfortunately, listening is a flawed substitute. In addition to the classic “sight over sound” shortcoming that’s noted above, listening yields insufficient data. Prominent performance issues are often hidden and might not be apparent when listening. E.g.: If a source impedance is too high relative to the ensuing load impedance (a common issue), the signal will then be attenuated. Obviously, one cannot readily detect unknown and unexpected attenuation. It’s tough to hear evidence that’s essentially inaudible, regardless of how glaring it might appear when quietly considered in technical analysis.

Impatient audiophiles who sometimes insist that “I know what I heard!” need to realize that…

     …the eyes always predetermine what the ears hear. The “sight over sound” syndrome (see above) is real.

     …what you do hear might not include everything that you should hear.

So what’s an audiophile to do, when there’s a need to evaluate audio equipment, if technical prowess is lacking and aural trials are unreliable? Well, some decide to search the audiophile forums. You can sometimes find helpful stuff there, perhaps at the Audio Science Review site (https://www.audiosciencereview.com/forum/index.php). But the audiophile forums are saturated with cult-infused groupthink†. They’re all about magic power line cords and miraculous speaker cables, curing power line impurities (to push AC regenerators), and the eternal blessing of everything that (still???) utilizes vacuum tubes. Aside from polishing one’s patience, there’s little to be learned at those fiefdoms. You can “smarten up” faster with other alternatives…

Check Audioholics, refer https://www.audioholics.com. Their full product reviews are exhaustive and well researched, and their technical advice reflects solid, science-based fact; no groupthink.

There’s a vast assortment of general information and DIY guidance provided on the exceptionally comprehensive Elliott Sound Products site. ESP is truly an essential treasure; it’s packed with reliable info and solid, science-based opinion. Do take just a moment—preferably right now—to scan the vital ESP articles and projects index pages.

     ESP’s main index—https://sound-au.com

     ESP’s general articles index—https://sound-au.com/articles.htm

     ESP’s project index—https://sound-au.com/projects.htm

     ESP’s projects by category index—https://sound-au.com/projects-0.htm

     ESP’s projects by number index—https://sound-au.com/p-list.htm

     ESP’s classic white paper on interconnect and speaker cables—https://sound-au.com/cablewhitepaper.htm

     ESP’s audio myths pages—https://sound-au.com/articles/myths.html

Prominent author Douglas Self’s site (http://www.douglas-self.com) is full of interesting audio-related fare, and serves as the reference shelf for his many books about all manner of solid state circuit design. I currently own three of Self’s design books, and I research their content frequently. (Self, who lives in the UK, has also been responsive in answering my inquiries about specific parts of that content.)

Audio industry icon Dr. Floyd Toole has a very helpful video presentation that’s well worth watching; see: https://www.youtube.com/watch?v=zrpUDuUtxPM&feature=emb_title, and his opus, Sound Reproduction, 3rd edition (Routledge, 2018, ISBN 978-1-138-92136-8) belongs in your audio research library. Do also note this paper, by Toole, which appeared on the Audioholics site: https://www.audioholics.com/room-acoustics/room-reflections-human-adaptation. It’s all about optimizing small room acoustics.

The prolific Ethan Winer (http://ethanwiner.com/index.htm) offers audio guidance on his multiple websites; also in the expanded 2nd edition of his 808 page book, The Audio Expert (http://ethanwiner.com/book.htm). It’s a well organized encyclopedic reference source for all things audio.

Bill Whitlock’s 2012 tutorial on audio system grounding and interfacing is well worth perusing, see https://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf. And Whitlock’s former company (he’s now retired), Jensen Transformers, has a comprehensive series of applications notes, AN001 thru AN009, that address related detail; see: https://www.jensen-transformers.com/application-notes/.

There’s useful general audio information available here: https://geoffthegreygeek.com. And Nuts and Volts, the DIY electronics magazine, offers this on filters: http://nutsvolts.texterity.com/nutsvolts/201807/?folio=16&pg=16#pg16. Sometimes Stereophile, the equipment review magazine, provides surprising guidance, like this info on output impedance…https://www.stereophile.com/reference/48/index.html. All worthy stuff.

In addition to the dozens of helpful papers compiled by the Audioholics team (https://www.audioholics.com), numerous product-specific manufacturer’s sites offer technical papers of merit. For example, Roger Sanders, of Sanders Sound Systems (where the principle product is hi-end electrostatic loudspeakers), offers 13 thoughtful, audio-related technical white papers; see…http://sanderssoundsystems.com/technical-white-papers. I personally recommend these papers without reservation. (Note: I’m not a strong proponent of electro-static type loudspeakers because they’re appropriate only in select situations. Full range ESLs are big, and require large listening rooms. They’re generally quite expensive, prone to narrow beaming, and all are inefficient; they eat lots (and lots!) of amplifier power. ESLs are also sensitive to some environmental variables (e.g., altitude, humidity), and some ESLs just seem to get buggy. All ESLs require periodic maintenance + careful cleaning, and all utilize hazardous high voltages.) Now please understand that my list of ESL caveats don’t have any bearing whatever on Roger Sanders’ excellent white papers, so read his papers. Use his ESLs, too, if they fit your personal profile. Sanders’ ESLs are probably the best ESLs that you can buy. They reflect all sorts of special measures to make them both practical and reliable, and they sound glorious, in addition to being highly accurate, but, hey, my stated comments still apply.

There are also good tech notes here: https://benchmarkmedia.com/blogs/application_notes, as compiled by John Siau, VP at Benchmark Media Systems. I don’t concur with his blanket implication that “balanced interfaces will provide better performance” (than unbalanced interface connections) at all times, but my objection applies only because John Siau’s unfettered statement was likely intended as a sweeping generalization. Clearly, there are times (especially in a home setup) when unbalanced RCA-type coax interconnects provide precisely the same level of noise immunity as when using balanced XLR lines. (Refer Roger Sanders’ paper on this same subject.) What’s optimum is often dependent on prevailing conditions.

What I’ve cited here is just a jump start. There are probably lots of other product-related sites with competent and unbiased guidance. But do take care, when considering technical advice, that the thrust is honest and impartial; not biased blather composed to push a product.

Subjectivist oriented audio magazines, e.g., Stereophile and The Absolute Sound, have never appealed to my science-oriented psyche. I subscribed to the latter for a one year trial back in the mid-1980s, then gagged on the content and cancelled. Your own take could well differ, but I don’t think that you will ever learn much of technical merit from their kind of commentary. The magazine audioXpress (https://audioxpress.com) represents the other extreme. It’s basically a tech-type journal covering audio equipment, circuit design, and testing, with a heavy DIY slant. I subscribe, and I find some of the articles of considerable interest. The editing is often sloppy, and some staffers write as if translating (sometimes poorly), and the technical depth varies widely. But it’s the best that we’ve got these days, so I’d say yes, order it here: https://audioxpress.com/page/audioXpress-Subscription-Services.

BG (July 15, 2020)

*Re. expectation bias, see…https://en.wikipedia.org/wiki/Observer-expectancy_effect.

**Re. confirmation bias, see…https://en.wikipedia.org/wiki/Confirmation_bias.

†Re. groupthink, see…https://en.wikipedia.org/wiki/Groupthink.