Date: Sun, 3 Dec 89 20:24:30 EST
From: kludge@pyr.gatech.edu (Scott Dorsey)
Subject: Playing Records Wet

Facts:

1. No record can be perfectly clean.

2. Playing non-perfectly clean LP's wet reduces noise.

3. Playing non-perfectly clean 78's wet does not reduce noise as much.

4. The grooves on 78's are wider than those of LP's.

5. The world is an imperfect place for audio reproduction.

Theories:

1. Playing records wet reduces noise caused by static discharge
     a. from reducing friction and corresponding static buildup
     b. from providing a conductive path to ground for the static charge.

2. Playing records wet reduces noise by keeping dirt in suspension.

3. Playing records wet reduces noise because the surface tension of the
   fluid keeps the record from jumping upward violently, without significantly
   dampening its motion.

4. Playing records wet reduces noise by dampening stylus movement, and also
   reduces high frequency response correspondingly.

5. Playing records wet reduces the high temperature caused by compression at
   the stylus tip and therefore less 
     a. brownian motion
     b. noise caused by conformation of molten plastic.

Possible Answers:

1. 78's tend to have less of a static problem, which would explain why
   playing wet does not cause as much of an improvement.  However, in very
   humid weather, there is still an improvement.  Likewise, playing with
   a light, nonconductive hydrocarbon causes a similar improvement.  Thus
   this is not the correct answer.

2. Test-- if a record is nitty-grittied, does playing wet make as much
   of a difference?  Is the improvement with a perfectly clean record as
   great as with the only slightly cleaned ones used for this test.

3. Test-- Measure the temperature at the stylus tip.  I don't know how.

4. If it is true that the overall effect is caused by damping of the stylus
   motion, it would explain why the 78 does not have as much of
   an improvement, because the motion is greater.  However, a thicker liquid
   would cause an improvement. Tests with silicones don't seem to reveal
   anything dramatic; therefore this is probably false.

Unsupported Statements:

1. I have been told that playing records wet does something to them which
   increases the surface noise if they are played wet, and that once a record
   is played wet it must be continued to be played wet.  I have not noticed
   this occuring.  The only explanation I can think of would be microcracking
   due to rapid cooling effects.