The science of reverb springs

[Paul Perry]

At 11:07 PM 23/02/99 EST, JWBarlow wrote:
>

>It is easy to imagine how the waves travel through the spring (in the ideal
>case) if you think of one side of the spring as having a speaker element which
>forces the spring back and forth (in a longitudinal manner) at the same freq.
>as the input signal. A small section of the spring will be compressed or
>expanded, and will "travel" towards the other side of the spring, when it
>comes to the end of the spring, it will travel back towards the driver element
>(see any good physics book on longitudinal waves). 

.....I have the feeling (but cant put my hand on actual evidence at the moment) 
that torsional waves, not longitudional waves, are used because:

1. they are much slower

2. they are less likely to be spuriously injected by knocks & bangs.

I once saw a 6inch steel wire loop with torsional input & output used as 
circulating memory in one of the first 'electronic' calculators (?1967?)

paul perry Frostwave analog fx melbourne australia