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 arecompared 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 classic white paper on interconnect and
speaker cables—https://sound-au.com/cablewhitepaper.htm
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. groupthink, see…https://en.wikipedia.org/wiki/Groupthink.
