Counter bearing treatment

[Richard Brekne]

Del... here are those figures you requested at the bottom of this note

The treble section (capo area)

distance between capo and first half round is 1 1/8 inch.
distance between first half round and second is 2 inches.
both sections are unmuted
deflection angle approximately 15 - 16 degrees.
distance from second half round to tuning pins is between 3 and 5 inches
depending on tuning pin placement.


Tenor section (aggraffed)

distance from the aggraffe to the first half round varies starting at 1 3/8 inch
at the lowest tenor...increasing to 2  inches midway through the section, and
decreasing again to 1 3/4 inches at the top end of the section. Unmuted

distance between first and second half round varies in similar fashion starting
at 2 1/8, up to 3 inches and then down to 2  7/8 inches.

There is a 1/4 inch felt strip under the strings approximately half way between
the two half rounds. The strings rest lightly on this strip, slightly muting
them but not pressing deeply into the strip

Deflection angle here is also about 15 - 16 degrees,, a bit more in the lowest
notes.

Distance again to the tuning pins is similar to the treble except the lowest 6-7
notes, where this gets down to less then a half an inch at the shortest. The
segment is unmuted

... grin.. so what can you tell me... I notice rendering problems intermittent
throughout the entire tenor / treble range of the piano. The bass is not so bad.
Also.. if I am to quite the duplex, is it better to do so by attempting to
constrict energy leakage instead of simply muting off, and if so.. what are some
good suggestions as to method ?

When you get the time... grin...

Thanks ever so much

Richard Brekne
I.C.P.T.G.  N.P.T.F.
Bergen, Norway

Delwin D Fandrich wrote:

> ----- Original Message -----
> From: Richard Brekne <richardb@c2i.net>
> To: <pianotech@ptg.org>
> Sent: January 11, 2000 1:19 PM
> Subject: Re: Counter bearing treatment
>
> > Del... this is of interest to me. I have this Grotrain that I have
> mentioned a bit about and it is more or less configured as Jon  re-configured
> his
> Baldwin. In addition in the treble section it has a non muted section between
> the
> brass half round which passes over a section brass half round (about 3 inches
> long) before going to the pins. The tenor is identical except that there is a
> thick felt strip about a half inch wide for the strings to rest a bit on..
> just
> enough to mute them.
> >
> > Problem is with this piano is that there is like tons of energy leakage
> through the aggraffes and even across the first half round. Drives me nuts
> really,
> and I have been considering using the wide felt rest common in Yamaha tenor
> sections.. and like what this Baldwin R had to quite it down. I have hedged
> tho as
> muting these sections isnt neccessarily going to help the fact that there is
> so
> much energy leakage.
> >
> > Oddly enough... this G.S. has quite a bit of rendering problems as well.
> >
> > Thoughts... suggestions ??
>
> ------------------------------------------
>
> Richard,
>
> What are the string deflection angles and how close are the counter-bearing
> bars -- and the felt strip -- to the agraffes?
> Del