Audio woo

From RationalWiki

Jump to: navigation, search
A classic example of the species.

Audio woo consists of unsupportable claims for devices or methods for getting better sound quality from systems that reproduce recorded music. Such claims are made by manufacturers, hobbyists, and writers in the field.

Contents

[edit] The quest for perfect sound

An audiophile is someone dedicated to producing the highest possible fidelity in the playback of music. While this can certainly be a reasonable goal, much of the industry that caters to them sells extremely high priced equipment that claims to improve sound through highly dubious mechanisms and/or badly misunderstood real science. Most double-blind studies have shown that there is no difference in detectable sound quality for most of the equipment sold,[1] and some of it is actually inferior in quality to less expensive products. Many of the products use appeals to magical thinking and pseudoscience to explain their mechanisms.[2] While some of them do indeed provide a small, subtle improvement in sound quality, the unscientific claims by the manufacturers as to why they might sound better lead to a subculture of people who are utterly deluded about how to get the best sound from an audio system.

These particular audiophiles are widely known in the electronics trade as people who put subjective sound experience above objective measurement as the primary way to judge sound reproduction; as a result, many refuse to admit that their beloved "warmer" sound (often lamented as having disappeared with the introduction of transistors, and then the compact disc) is actually a form of distortion. Double-blind testing, as in many other pseudoscientific pursuits, is shunned since it removes the power of suggestion (by brand name, equipment appearance, or price) from the testing room and has a frustrating inability to confirm their prior prejudices. At the extreme end of this particular brand of audiophiles are the "tweakers" whose obsession leads to belief in some of the more bizarre claims (read scams) of the subjective audiophile industry.

There exists an inverted class of audiophiles who claim that the sound of vinyl, i.e. records played with a contact stylus, is superior to the sound of compact discs or other digital music - a interesting school of thought given the analogue/digital audio debate.

An anonymous wag, in the tradition of The Devil's Dictionary by Ambrose Bierce, once defined such an audiophile as someone who listens to the stereo, not the music. Indeed, there are even people who collect and assemble such systems with no goal of even listening to music!

[edit] Psychological explanations

Explanations for why manufacturers, audiophiles and the "tweakers" perpetuate the myths of the subjective audio crowd are varied but one simple explanation is cognative disonance. Put simply, having just spent thousands of dollars on something that does very little or nothing the duped purchaser adjusts their thinking from "I can't believe how dumb I have been" and "my wife will kill me!" to "Wow! spending hundreds of dollars on little rocks in jars has opened up the sound stage and increased the clarity of the such and such." The brilliant thing about the cognative disonance effect is that it works in inverse proportionality to how dumb the purchase was - so the more ridiculous the tweak the more believing the purchaser will be.[3] This brings into question the review policy of subjective audio reviewers such as Positive Feedback, where reviewers often own the equipment they are reviewing.[4]

Explanations can also include the concepts of buyer's remorse which can actually fuel the cognative disonance effect and the observer expectancy effect

[edit] The tube thing

Subjectivist audiophiles often express a preference for tube-based amplifiers due to their perception of a cleaner sound, to the point where scam artists have sold products claiming to make transistors function like tubes. (The effects of such devices on MOSFETs such as are found in the vast bulk of DSPs and other computer chips are not elucidated.)

As a general rule, to mainstream audio folks tubes are not inherently bad, though perhaps a bit high-maintenance; however, while tubes are very popular in guitar and other instrument amplifiers due to their unique sound (a type of distortion resulting from soft clipping), they are considered somewhat unnecessary in playback amplifiers. Skeptics of tube amplifiers argue that audiophiles prefer the inherent distortion provided in the antiquated technology while paradoxically claiming the sound is purer and more perfect. [5]

[edit] The vinyl thing

A great many audiophiles hold up vinyl records as being the be-all, end-all of sound reproduction. Vinyl, though largely obsolete, does have a few uses, particularly archival (it's substantially more robust than optical or magnetic media), and it's also the original medium for turntablism, the aspects of DJing that involve scratching and mixing and generally using the console as a musical instrument rather than a playback device.

However vinyl records, inevitably wear out from the ensuing scratching, especially with use of a needle rather than a laser or a scanner. Dynamic range is also limited -- depending on bandwidth, sample rate, and storage capacity, a digital format can equal the performance of an analog medium of equivalent bandwidth (a CD, which can sample just outside the range of human hearing, can produce a much more faithful representation than a standard vinyl LP, which sometimes sounds fuzzy in comparison to a CD due to the lack of extreme treble). In addition, low-end turntables seldom maintain an even speed, often introducing pitch variation ("wow" and "flutter") as well as transmitting mechanical noise ("rumble") through the needle.

[edit] The bi-wiring thing

One of the most all pervasive audio woos is the notion of bi-wiring speakers. This is where you buy twice as much cable so that the woofers and tweeters can be powered separately using an extra set of contacts on the speakers. This allegedly prevents "cross talk interference" or something but essentially does nothing except make you spend more money. Unless there are completely separate amplifiers used to power the high and low ranges, the effect is the same as simply using a double thickness wire as nothing changes electronically (or audio-magically) to the circuit whatsoever due to superimposition principle.[6] Unfortunately, few hi-fi speaker manufacturers dare to release speakers without bi-wiring ports as the all-prevailing nature of the myth would mean they simply would not be able to sell them. To quote an honest manufacturer:

"Will it sound any different if you biwire? Some users think it does, but I've never heard any differences, nor have any of our laboratory measurements or scientifically controlled double blind listening tests ever demonstrated there are audible differences. Axiom includes the extra terminals as a nod to those enthusiasts who believe that biwiring results in audible benefits and for the bi-ampers."[7]

Note that the bi-wiring inputs provided are essential for those who intend to bi-amp their speakers. However, as many of these speakers contain passive crossovers, it would seem that they defeat the purpose of bi-amping, the supposed benefits of which are derived precisely from avoiding these crossovers.[8]

[edit] Magical cables

Over-engineered and insanely expensive power cables are perhaps the easiest woo item to dismiss. The claim that 6-feet of $1,800 power cabling (basically just a kettle lead) improves sound quality is ludicrous for the same reason that using such a cable won't make a DVD player display a sharper picture, although similar claims are made to that effect.[9] The claim also ignores the many hundreds of miles of boring cable being used to deliver the electricity to the house of the woo devotee. It's a bit like storing water in an old rusty bucket, and expecting the water to magically taste better if drunk through a really nice straw.

The effectiveness of the magical power cable would rely on the following assertion: The characteristics of the electricity are being altered by their passage through the magical cable.

Luckily this is can be very easily tested, although this is not something to do at home! The following steps are dangerous to you and your equipment, and provided for illustrative purposes only. Do this stuff at your own risk.

You could hook-up an oscilloscope or a spectrum analyzer directly to the mains current. This provides a baseline measurement. Next you can take the same measurements with both a regular power cord, and then with the expensive cable. There may be minor differences, but anyone qualified to use (and in possession of) an oscilloscope and a spectrum analyzer would likely see no significant differences.

The AC mains current will run through a transformer in order to adjust the power before it's routed to the various components of the equipment. The same measurements can be applied to the outputs of the transformer to see if swapping the power cords makes any difference. This is ideally done as a blind test, so that the person taking the measurements doesn't know which cable is currently being used. At this stage, it's remarkably unlikely that there will be any difference in the readings.

If there are no obvious difference found in these tests, then how on earth could the power cord be making a difference to sound quality? Fairies cleaning the electrons in some way invisible to physics?

In addition to power cables, you can now buy expensive audiophile cables for data. $500+ Ethernet, USB and digital interconnect cables are available if you are willing to ignore all that rubbish about the how digital signals aren't affected by cable quality at the short distances found in the average home.

Audio cables are inherently very cheap to make, store and transport. The vast majority of cable sellers do not manufacture anything: they choose products of large, industrial-size cable makers and specify cosmetic changes that aid brand differentiation. This is always accompanied by huge markups. This is abetted by the fact that audio cables have practically zero maintenance, spare-part, and after-sales service costs.

Audio dealers also favor expensive cables, as they can add their own excessive markup on products that cannot malfunction and will never require servicing, spare parts, or any kind of dealer support. Many dealers utilize a "fake choice" trick on unsuspecting consumers: they are quick to loan a variety of cables for a home trial, giving the consumer the "choice" of keeping and paying for the cable they prefer and returning the rest. The returned cables have no sign of having been used before and retain their "brand new" status and perceived value. The consumer is thus fooled into making an entirely free choice (between similarly overpriced products) and the dealer clinches a profitable sale regardless.

[edit] Abuse of science

As more and more of the audio chain becomes integrated and non-user-serviceable, some hobbyists have begun to focus on small bits of solid-state physics in the attempt to tweak ever smaller performance gains out of their equipment. As a result, they invoke much pseudoscience in order to justify massive cost outlays for things like marble turntables and $100+ power cables.[10]

  • The green marker thing: It was rumored at one time that coloring in the edge of a CD could make the disc sound better; in response to skeptical comments that "bits is bits" (i.e. digital data sounds the same no matter what source it comes from), some audiophiles have offered the ad hoc idea that the green marker prevents stray laser reflections... or something. Though no longer as widely believed, the markers are still available and sold explicitly for that use.
  • Treating CD surfaces: While it is true that a clean CD is a good thing, a cult developed around "treating" the playing surface of CDs with Armor-All (specifically) to improve the sound.
  • Skin effect: In radio engineering, signals in the VHF, UHF, and microwave bands sometimes tend to congregate on the outside of a conductor, increasing the effective resistance of the conductor and causing signal leakages at sharp bends in the conductor, requiring careful laying of antenna and patch cables to avoid signal loss. While the effect is negligible to nonexistent at audio frequencies, some audiophiles nevertheless place great emphasis on avoiding skin effect. (It is of some concern in high-bandwidth video applications, but for the most part people don't obsess nearly as much over S-Video cables.)
  • Hyperseparation of channels: Numerous audiophile systems avoid stereo power amplifiers, using so-called "monoblock" (i.e. single-channel) amplifiers to completely eliminate interchannel crosstalk. While fairly harmless in terms of function (though not necessarily to the audiophile's wallet), it is generally considered overkill by sound engineers.
  • Obsessively shortening the signal chain: Given the opportunity, many audiophiles would prefer to avoid as many amplification stages as possible, to remove even the tiniest loss of signal definition. As a result, some audiophile systems eschew even a preamplifier, piping the output from the playback device directly to the power amp. Sound engineers find this to be especially hilarious in light of the vast number of op-amps in any given mixing board.
  • Esoteric cabling: Manufacturers gladly pretty much make up pretend scientific-sounding reasons for why their incredibly expensive interconnects and speaker wires are supposed to sound better. There is also a sub-cult of people who think their speaker wires sound better if they are supported on magical insulators. At least one test found that audiophiles couldn't tell the difference between coat hangers and fancy Monster brand cables used as speaker wires.[11] Super-technobabbleific woo is particularly hilarious when applied to digital cables (S/PDIF, HDMI, etc); again, bits are bits and bit loss is often more than readily apparent.
  • The magical clock: A particularly ingenious scam artist once sold a "specially modified" digital alarm clock for $400 each. Plugging it into the mains outlet was supposed to effect amazing improvements in the quality of sound. He also sold a number of other strange things, like little bits of foil to stick to things. The subjectivist audio press were duly impressed.
  • Another outfit, that also makes a magic clock,[12] also offer to teleport better audio and video reproduction thousands of miles - over your phone. Genius. [13]

[edit] Sometimes "right"

While many of the claims made by audiophiles are rightly derided as pseudoscience or woo, there is a track record of so-called "golden ears" being right about some things that "engineers" failed to get right. A few examples:

  • Early solid state amplifiers (and even some later ones), while measuring far better than their tube (valve) predecessors, sounded worse. It turned out that careless use of too much feedback to reduce harmonic distortion (THD) was causing intermodulation distortion (IM) artifacts. Of course, once the engineers realized this, they solved the problem. Early transistor amps were also producing large amounts of "crossover distortion", a kind of distortion that is produced neither by tubes nor by transistors operating in "Class A" (continuous operation) mode, and is caused by transistors switching on and off ("Class B", where the NPN and PNP transistors only conduct one half of the waveform and then have their outputs combined). This has been greatly ameliorated by "idling" the transistors during the off period of their duty cycle (the so-called "Class AB" mode). It continues to be a problem with extremely sensitive speakers, where amps need only output a few milli- or even micro-Watts of power. In such cases Class A amps are used, as they have no crossover distortion by definition.
  • Early CD players were accused, in spite of their "perfect sound forever", of sounding nasty compared to analog equipment. The "brick wall" filters at around 20-22 kHz used to keep digital artifacts out of the reproduction chain were creating unpleasant phase effects in the audible region. Better ways of eliminating these artifacts (oversampling, over 16 bit converters, single bit converters) eliminated this problem. Many early CDs were also mastered poorly, since engineers were not used to the nature and requirements of the format, and this led to them sounding harsh. With decades of experience in digital recording and mastering, this is no longer an issue.
  • Most contemporary CDs are mastered very aggressively, with the purpose of their being listened to in very noisy environments (car radio, personal audio devices used in urban environments etc). The trend has been named "The Loudness Wars" and makes for CDs that sound too loud and too compressed in a normal home audio situation. This kind of mastering could not and cannot be done on vinyl records, as they would then present excessive tracking demands to the pickup cartridge and cause distortion or record skipping. Consequently, an LP version of the same music can sound much more naturally mixed and mastered than its CD equivalent, which has been artificially "optimized" in the studio for use in noisy environments. This is not an inherent equipment fault, but the result of deliberate marketing decisions made by music sellers.
  • Over very long lengths, cables can affect audio quality if the gauge of the wire is insufficient. Thin speaker cable at lengths of 50 feet or more will show a noticeable drop in quality.[14] Similarly digital cable over very long lengths will show noticeable signal degradation. However these are issues that could only really effect very large venues such as stadiums and concert halls where industrial grade (and relatively cheap) cable is used. This is the grain of truth that is heavily manipulated to sell very expensive cable to the monetarily overburdened.

There are other examples, but, sadly, these truths tend to encourage careless audiophiles to set greater store than appropriate to every wacky claim put forward, both by manufacturers and "golden ear" reviewers.

[edit] See also

[edit] External links

[edit] Footnotes

  1. ↑ Write up of double-blind test for audiophile equipment
  2. ↑ Article on audiophiles
  3. ↑ Audiophiles and the Limitations of human Hearing
  4. ↑ Positive Feedback's Review Philosophy
  5. ↑ The Audio Critic issue 26 The 10 Biggest Lies in Audio
  6. ↑ The Audio Critic issue 26 The 10 Biggest Lies in Audio
  7. ↑ Axiom Audio
  8. ↑ The basics of bi-amplification
  9. ↑ AC power filter: I can't see a difference, but I know it's there!
  10. ↑ $1,800 dollars for a power cord? I'll take 2!
  11. ↑ Do coat hangers sound as good as Monster cables? Yes. Yes they do.
  12. ↑ Machina Dynamica's Clever Little Clock
  13. ↑ Machina Dynamica's Teleportation Tweak
  14. ↑ Misleading Wire Demonstration
Retrieved from "http://rationalwiki.com/wiki/Audio_woo"
Personal tools