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From: kaepplein@amber.DEC
Newsgroups: net.audio
Subject: Re: Tighter bass and edgeless piano
Message-ID: <511@decwrl.UUCP>
Date: Fri, 20-Sep-85 12:18:08 EDT
Article-I.D.: decwrl.511
Posted: Fri Sep 20 12:18:08 1985
Date-Received: Sun, 22-Sep-85 19:02:40 EDT
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Organization: Digital Equipment Corporation
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>Is there another domain of sound reproduction that has escaped 
>detection by electronic instruments but is be obvious to the ear?
>Everything happens for a reason and anything that can be heard
>can be measured.
 
Yes.  Julian Hersh and the manufacturers measure mostly static performance
with sine waves.  There are two problems here.  The first is that sine
waves poorly represent typical source material, and that the only test
instrument that counts in the end is the ear.  Music is very transient
and ears are very sensitive to signal attacks among other things ( I
don't have my psycoacoustics and computer music texts handy).  If you
are lucky, some reviews will publish a picture of a sine wave or impulse
but they won't tell you the numbers for overshoot or the period/frequency/
cycles of ringing.  Designers would love a subjective and quicker way of
assessing performance than listening.

There exists circuits for measuring distortion caused by capacitors.
John Curl published one in the letters section of August's HiFi News
and Record Review.

>If someone does know what is happening with the CD 1040 mods
>and can offer a rational explanation of why, fine.  I want to
>learn.  Maybe we can all learn.    Maybe even some of us can develop
>less costly and equally useful methods for accomplishing the same results.

First of all, a modified 1040 is much cheaper than a Nakamichi or a
Mission or a Meridian.  $330 is about what most players cost.  I suggested
the modification places for those not willing or handy with an iron.

For under $10 you can replace the electrolytic DC filtering capacitors
with film capacitors.  Most CD players/VCRs/laser disk players/receivers
could use this too. Electrolytic caps smear transients.

For another $5, you could replace the opamps.  The problem is that I
don't know much about opamps and could not tell you which ones will
have lower distortion than the NE5532's Phillips uses.  Besides parts
and labor, you are paying mod houses for their intelectual property.

The two most important changes can be made for the cost of a disk.
The most expensive change, a good audio cable, might come next.
These are problems that are not solved with equalizers or ambience
recovery modules.  Fixing it amounts to the manufacturer spending an
extra $10 but charging consumers an extra $500+

The Magnavox is not a bad unit.  I'm sure Julian Hersh would say that
its sounds just as perfect as any other player and would laud its immunity
to shocks.  It's a bargain in a market filled with outrageous hype.

>Terry L. Zrust

Mark Kaepplein