Unison beats good?

[Don]

Hi Bill Bremmer,

Misquote of the article--why am I not surprised?


At 10:05 AM 11/6/98 EST, you wrote:

>
>There was a story in Scientific American about 20 years ago called "The
>Coupled Motion of Strings".  Not having the text for reference, I remember
>that it concluded more or less that the best tuners produce this kind of
>error.  My personal opinion is that the tuner strives for a perfect unison
>which means "no beat".  If there is a 1/2 beat per second or less, the tuner
>may be satisfied with it because the beat is simply inaudible. 
>
> I think it can matter depending on the circumstances.  In a usual, in-home
>tuning that I do on a piano say, once a year, I won't listen to a unison long
>enough to even know if there is that slow of a beat.  During a concert tuning
>however, I may pound away at a unison for a considerable time, just to make
>*sure* there is no hint of a beat.
>
>From what I have learned, the unison is really the only interval where it is
>even possible to have absolute perfection and that is the goal.  5ths and
>octaves can *sound* pure and thus be perceived as beatless but we know from
>the understanding that has come about in recent years that inharmonicity
>prevents coincident partials from ever lining up perfectly.  Therefore, there
>is always some kind of beat in these intervals whether it is perceptible or
>not.
>
>When tuning the 5th and the octave, the tuner may choose to favor one set of
>coincident partials over the other or may make a compromise between them in
>order to create a desired effect, expanded or contracted, as desired.  With
>the unison however, I believe the consensus has it that it is to be absolutely
>pure or as close to that as possible.  The very small variances that have been
>noted in the unisons of the best tuners are a result, I believe, of the
>physical limitations of both the piano and the tuner him/herself.  An error of
>.1 or .2¢ is *readable* by an ETD but probably inaudible to the ear.
>
>Furthermore, there is always the dilemma of the False Beat.  Practically no
>piano is completely without them.  It is possible that some very skillful and
>artful tuners can in effect, cancel out a false beat by countering it with a
>deliberate but slight beat in the unison.  In such a case, the three strings
>would most surely have as much as (or perhaps even a little more than) a full
>cent difference between them.
>
>Sincerely,
>
>Bill Bremmer RPT
>Madison, Wisconsin
>
>
>
Regards,
Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T.
"Tuner for the Centre of the Arts"
drose@dlcwest.com
http://www.dlcwest.com/~drose/
3004 Grant Rd.
REGINA, SK
S4S 5G7
306-352-3620 or 1-888-29t-uner