Weinreich unisons(wasTuneoff)

[Richard Brekne]

A440A@aol.com wrote:

>
>
>
> Greetings,
>    Gabriel Weinreich (I hope I am spelling it right), published  "The Coupled
> Motion Of Piano Strings" in the late 70's.  The gist of his research was that
> the coupled motion required, at times, that the strings not be tuned to the
> exact same pitch in order to produce the longest sustain and clearest
> sounding tone.
>    In a short summation,  the coupling of the various strings causes them to
> interact via the bridge.  With two strings, it is rather simple, but with
> three, there can be several overlapping phase relationships.  It can become
> as complex as the salt-spray on the ripples on a wave on a swell on the
> ocean!  If all strings are perfectly matched, the energy from the hammer is
> "dumped" into the bridge, all at once.  The bridge moves a lot when this
> happens, causing the energy to used(transmitted) all at once.  The resulting
> note may be louder at impact, but suffer a loss of sustain and bloom.
>    If the strings' vibrations are hitting the bridge in an opposing pattern,
> they tend to stiffen the bridge against the oncoming pulse from the other
> string.  This stiffening is responsible for more of the energy being
> reflected back into the string, causing the sound to sustain longer.   A
> careful ear can hear the tonal difference in a unison that results from very
> small changes.

This was a really nice simple explanation Weinrichs paper. Since first reading
this I have wondered many times why no follow up was done to look more closely
into how intervals other then "simple" unisons behave an intereract. I aggree
with  Ed, that a carefull ear can hear the tonal difference in a unison that
results from extreme small changes. I would take it farther tho and say that this
same carefull ear can hear tonal differences from similiar manipulation of
octaves, double octaves and other intervals.

This lies at the heart of why I use my laptop programs less and less for directly
tuning pianos. I am far from convinced that the algorithm that lies at the core
of single partial CC electronic tuning aids is the ultimate answer for ET
tunings. Or any other temperaments for that  matter. Sure they do a fine job and
create an affect all their own. But it is a very singular effect, and the machine
is not capable of doing anything else, nor of solving problems that dont fit into
that algorithm.

I also believe that this kind of phenomena lies at the heart of what our freind
Virgil has been trying to describe to us. This "blooming" effect of unisons can
be very "beat-like" to the ear really. At least thats how I experience it. And it
definatly is apparent in octaves and double octaves and its' presence in these
are definiantly  not always coincident with any particular calculated single
partial curve. Which really says that a very interesting alternative to the CC
ETD's presents itself for us to explore.

I think Bill Bremmers references to the canceling affect that different beat
rates can sometimes have on each other are also a part of all this. All in all I
think there is way to much a tendency to just accept that present ETD's
(verituner not included as I am still not sure how it goes about calculating a
tuning) and the basic approach of single partial calulated curves they employ are
the last word on tuning. There is loads of stuff we havent even begun to look at
yet. Heck thats where all the fun is.... check it out... use your ears !

JAO

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