ETD question re: unisons

Richard Brekne Richard.Brekne@grieg.uib.no
Wed, 14 Feb 2001 21:50:20 +0100


Nothing questionable about this at all really. Coltman talks about this as far
back as 1935 if I am not mistaken, it was dealt with in no small measure in the
Five lectures, and the phenomena has been measured many times by many folks
both using everything from rather crude to extremely sophisticated devices.

What is argued still is more a matter of what exactly causes this. I like the
String coupling arguement as presented in the Five Lectures. You may read this
online of course. One of our Swedish colleagues has gone to great personal
effort to make this out of print document available again.  You should read
through it if these kinds of questions interest you.

Ron N has gone to some effort to check out how consistantly this drop occurs
through the scale I believe, and I think he believes there is some connection
between the soundboard / bridge configuration and the amount of drop at any
given spot. In particular he looks at the so called killer octave. I am sure he
will be willing to impart a bit more detail his observations.

I find his ideas actually go quite well with whats written by the authors in
the Five lectures. In the lectures the frequency of coupled strings change
(visa vi non coupled strings) dependant upon the character of the bridge. The
bridge, being not entirely rigid may be either "springy",  "massy" or
"resistive" in character and each condition effects the frequency of
non-coupled strings differently. Coupling in second and third strings,
influences the impedance felt by the first string, and a frequency shift can
occur.

According to this lecture the frequency of coupled strings can actually move in
either direction. It may also remain the unneffected yet accompanied by an
increase in decay time. All depends on the type of impedance of the bridge
itself, and the impedance of the strings.

Read the article... its very interesting stuff, but you may find yourself
having to read through it more then twice to sort it out....:) I did in
anycase.

"Howard S. Rosen" wrote:

> Hi everyone,
>
> Since I know nothing about ETD's my question might be naive. Nevertheless
> here goes: I believe that Virgil's assertion that a 3 string unison is
> flatter than each of the single strings heard singly, is a bit questionable
> or should I say not fully accepted. Wouldn't it be easy and conclusive to
> check this thesis by using an ETD to measure this? Thanks!
>
> Howard S. Rosen, RPT
> 7262 Angel Falls Ct.
> Boynton Beach, Fl  33437
>
> hsrosen@gate.net

--
Richard Brekne
RPT, N.P.T.F.
Bergen, Norway
mailto:Richard.Brekne@grieg.uib.no




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