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From: simard@loral.UUCP (Ray Simard)
Newsgroups: net.audio
Subject: Re: What does "distortion" sound like? - (nf)
Message-ID: <153@loral.UUCP>
Date: Sun, 20-May-84 13:17:18 EDT
Article-I.D.: loral.153
Posted: Sun May 20 13:17:18 1984
Date-Received: Mon, 21-May-84 05:41:30 EDT
References: <32900004@convex.UUCP> <346@drutx.UUCP>, <494@opus.UUCP>
Organization: Loral Instruments, San Diego
Lines: 34


	One thing that seems to be overlooked here is that there is more
than one kind of distortion.  There's frequency distortion, in which
some frequencies are reproduced at a different level from others relative
to the original source material, phase distortion in which some frequencies
are shifted in phase relative to others, and harmonic distortion, in which
frequencies are generated that were never present in the original material.
Of these, the first is sometimes desirable (that's why equalizers, not to
mention tone controls, exist).  I cannot at the moment imagine a useful
purpose for the second, though there may be one. The third is just plain
trash (unless used for effect, like a rock guitarist's fuzzbox).  

	It's my guess that harmonic distortion is the prime subject of
the 'what does it sound like' question.  If so, the answer is somewhat
complicated, and subject to the listener's interpretation.  To me, 
a harmonically distorted program sounds strained and muddy, as if something
in the audio chain is being asked to do something of which it is not
capable.  Sometimes very short peaks of high-frequency material are clipped
which results in a strange perception of irritation.  Although the harmonics
generated are above human hearing, there is a perceptible effect anyway.

	In most modern equipment of any quality, THD (total harmonic
distortion) levels are so low that one usually cannot hear the distortion
directly.  However, I find that when listening to a superlative system
there is a clarity and distinctness to the sound that is lacking in
middle-of-the-road gear.  Also, stereo imaging is more definite, adding
to the illusion of an actual performance.  A friend of mine has
a Hafler amp and a pair of Dahlquist speakers, and a high-end turntable
(I don't recall the name).  He has also furnished his room to avoid
resonances and other damaging effects.  To hear this system is to enter
a very special world.

Ray Simard