[78-L] Removing hiss

[Steven C. Barr]

We can assume the outside groove of a 10" 78 is about 9.9" in diameter; its
length (9.9 * pi) is a bit over 31 inches. This length must be traversed in 
1/78
of a minute (.77 seconds), or a speed of 40.4 ips.Since one cycle of a 6KHz
sound lasts .00167 seconds, its "waveform" on the record will be about 
.0673"
long. So...if the particles of "filler" which generate the typical "hiss" on 
78's are
around .0673" across/in diameter, they will generate "noise" of c. 6KHz when
the record is played. AFAIK, there is no practical way to tell the 
difference
between the groove path created by a 6KHz signal...and one caused by a
"stray" particle of filler with a size identical to that signal...?!

Steven C. Barr