[78-L] Record Noises - Identify and Understand Cause

[Dave Burnham]

It is easy to see blasting on a record; blasting only occurs on loud peaks, (if we're talking about the same thing), and it appears as a grayish arc superimposed on the loud groove. I've always called it torn groove and it occurs when a large lateral excursion, (loud), is tracked repeatedly with a needle or stylus with poor compliance. You'll often find blasting on multiple copies of the same record. You'll rarely find a copy of Crosby's 1935 "Adeste Fidelis", or the 1939 Aldershot "Last Post" or the Bourdon "Jingle Bells Fantasy" without blasting on their last notes;  however, the D'Oyly Carte recording of "Yeomen of the Guard" has blasting throughout on choral peaks which has no visible evidence because it was caused by sloppy engineering, not groove damage. 

db

Sent from my iPhone

> On Jan 13, 2014, at 11:50 AM, "neechevoneeznayou at gmail.com" <neechevoneeznayou at gmail.com> wrote:
> 
>> On 1/13/2014 10:24 AM, Doug Caldwell wrote:
>> is there any way to visually tell if a record has "blasting"
> 
> If you mean by the naked eye, I think so. If your vision is strong 
> enough, you could look at the groove and see that it appears to be 
> "wider", meaning it produces a wider lateral movement for the stylus on 
> peaks. Easier to see when comparing a pristine copy to a worn copy. Also 
> easier when your eyes are young. Otherwise, a strong magnifier helps.
> 
>>> And if you look at blasting on a graph, it's a ton of spikes (like a
>>> lotta ticks close together).
> 
> If you mean on the computer screen, David has answered that. The sound 
> produced may include high frequency artifacts that get more intense on 
> peaks. I am not sure what David means by a "graph". Perhaps a spectral 
> display? This is amplitude and frequency as a function of time. Makes 
> everything visible.
> 
> joe salerno
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