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Re: [Phys-l] Advertising bad physics!

Audiophile equipment has always been a focus for 'cost of diminishing returns' analyses. I suspect most of these claims have some physical basis. For example, tube amplifiers DO sound different than transistor amplifiers--at clipping. This is measurable--at least the waveforms are--and 'golden eared' audiophiles claim to hear the difference. OTOH, many double blind tests have been done that indicate that basically no one can tell the difference in most electronics (speakers are another matter). [However, BOSE once tried to market an amplifier that had up to 3% Harmonic Distortion claiming no one could discern it at that level and the unit could be more powerful for the money with that compromise. No one would buy it when other amps advertised .1% distortion.]

Expensive cables are a scam however. The only performance difference that can be measured and perhaps become audible or visible would be corroded contacts. Gold plated connectors usually don't suffer from this, but certainly silver and the more common aluminum connectors do. However, simply unplugging and replugging connectors about once a year takes care of any problem. I had a heated discussion with the 'sales people' at best buys about their $50 HDMI cables (nothing cheaper) as being a pure scam. Then I went online and bought 3 cables for under $20 total.

So, I agree this might be a good assignment (for sufficiently advanced classes--since the 'physics' here can be above intro level stuff). In the end though, it is often similar to comparing a Mercedes (or even a Rolls) to a Civic--yes they are better, but are they 5-50 times better?

Rick

***************************
Richard W. Tarara
Professor of Physics
Saint Mary's College
Notre Dame, IN
rtarara@saintmarys.edu
******************************
Free Physics Software
PC & Mac
www.saintmarys.edu/~rtarara/software.html
*******************************


----- Original Message ----- From: "John Clement" <clement@hal-pc.org>
To: "'Forum for Physics Educators'" <phys-l@carnot.physics.buffalo.edu>
Sent: Friday, December 05, 2008 12:24 AM
Subject: [Phys-l] Advertising bad physics!


Advertising has always been around and it is designed to fan desire while
keeping hard information minimal. I always remember my grandfather saying
that in radio he had to read commercials advertising a "genuione 24 carat
simulated gold ring" at a low price. So when I got a catalog from MD music
direct I should not have been surprised at the hype. However I was dismayed
by the outrageous use of physics/engineering terms in a meaningless or even
outright wrong fashion.

Ok, it advertises outrageously priced gear with PRESTIGE value. So can one
truly say that a $5000 tube amplifier is better than an equivalent
transistor one? It certainly has power! It wastes energy like crazy and
provides a warm glow sort of like a fireplace, and has prestige. They do
have some sensible things, at what I think are inflated prices. But a
number of items just caught my eye.

1. A $39 to 119 mat can be placed on top of a CD before loaded. It will
"reduce read errors" and "eliminate transport resonances" so you hear
"better dynamics, a lower noise floor and smoother high-frequencies" Hmmm

2. Disc Demagnetizer $399 - "removes residual magnetism from and disc
(spinning a disc creates and increased static charge). You'll hear better
tonality, a wider, taller and deeper soundstage..."

3. Audioquest cable $1500/m. has a metal upgrade in addition to Perfect
Surface Silver conductors "offers outstanding resolution, with far greater
clarity and speed than copper conductors" I wonder what type of cables they
use for making the recordings?

4. Audio Points $35-45 + $10 coupling disks - These are listed among the
flexible devices used to dampen vibrations. They are made of brass and are
shown with the point down. "Best sounding cones on the market. A unique
geometry maximizes energy transfer through specially tuned solid brass.
They displace the focal point of the resonant energy to a virtual point
below the tip of the Audio Point."

5. Myrtlewood golden cuboid blocks - also listed in the audio dampeners.
"is denser than Oak and has a very complex grain structure, making it an
excellent resonance damper. The blocks employ dimensions corresponding to
the Golden ratio, which Cardas uses in its cable designs. They can be used
under any component, including speakers" The picture shows a straight
grain.

6. Wandia iTransport - This device uses a digital signal from the iPod for
an external DAC to make it a high end source. Let us remember that iPods
generally use lossy compressed digital audio.

7. AC outlets and cords of pure copper, gold plated $99 claim to make a
better contact so the sound is better.

8. Creative cable concepts pigtails $125/pair - These "pigtails are
designed to eliminate Back-EMF, a nasty audible distortion crated by
backward movement of cone and dome drivers." They "attach to the positive
binding post on your speakers. Instantly, the image comes into focus..."
These are passive devices.

9. ENACOM Speaker Noise Eliminator $99/pair - "attach across he terminals
of speakers reducing noise caused by load resistance distortion and RFI
picked up by unshielded speaker cables". Do speakers respond to RFI?

Please forgive my touch typing while reading the ads.

Some of these may have a germ of truth, and may merely be ignoring the fact
that they are third or perhaps 33rd order effects which are negligible
compared to much bigger problems. There are many more claims which I find
to be equally dubious, but I do not have time to read every ad.

Perhaps students could research some of these claims and see if they make
sense. Nowhere has anyone mentioned double blind listening tests which are
possible to do with audio equipment. Also a number of ideas seem to be
coming from the analog world are ignoring the reality of controlled power
supplies and digital technology with built in error correction.

In these ads one sees the echoes of many common student misconceptions.
These ads also resemble conventional textbook ads with all kinds of claims
and testimonials, but no hard evidence.

John M. Clement
Houston, TX


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